summaryrefslogtreecommitdiff
path: root/libavcodec/mlpenc.c
blob: 7693feb12749fd8207fac80c11142901bb9fe011 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
/**
 * MLP encoder
 * Copyright (c) 2008 Ramiro Polla
 * Copyright (c) 2016-2019 Jai Luthra
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "avcodec.h"
#include "encode.h"
#include "internal.h"
#include "put_bits.h"
#include "audio_frame_queue.h"
#include "libavutil/crc.h"
#include "libavutil/avstring.h"
#include "libavutil/samplefmt.h"
#include "libavutil/thread.h"
#include "mlp.h"
#include "lpc.h"

#define MAJOR_HEADER_INTERVAL 16

#define MLP_MIN_LPC_ORDER      1
#define MLP_MAX_LPC_ORDER      8
#define MLP_MIN_LPC_SHIFT      8
#define MLP_MAX_LPC_SHIFT     15

typedef struct {
    uint8_t         min_channel;         ///< The index of the first channel coded in this substream.
    uint8_t         max_channel;         ///< The index of the last channel coded in this substream.
    uint8_t         max_matrix_channel;  ///< The number of channels input into the rematrix stage.

    uint8_t         noise_shift;         ///< The left shift applied to random noise in 0x31ea substreams.
    uint32_t        noisegen_seed;       ///< The current seed value for the pseudorandom noise generator(s).

    int             data_check_present;  ///< Set if the substream contains extra info to check the size of VLC blocks.

    int32_t         lossless_check_data; ///< XOR of all output samples

    uint8_t         max_huff_lsbs;       ///< largest huff_lsbs
    uint8_t         max_output_bits;     ///< largest output bit-depth
} RestartHeader;

typedef struct {
    uint8_t         count;                  ///< number of matrices to apply

    uint8_t         outch[MAX_MATRICES];    ///< output channel for each matrix
    int32_t         forco[MAX_MATRICES][MAX_CHANNELS+2];    ///< forward coefficients
    int32_t         coeff[MAX_MATRICES][MAX_CHANNELS+2];    ///< decoding coefficients
    uint8_t         fbits[MAX_CHANNELS];    ///< fraction bits

    int8_t          shift[MAX_CHANNELS];    ///< Left shift to apply to decoded PCM values to get final 24-bit output.
} MatrixParams;

enum ParamFlags {
    PARAMS_DEFAULT       = 0xff,
    PARAM_PRESENCE_FLAGS = 1 << 8,
    PARAM_BLOCKSIZE      = 1 << 7,
    PARAM_MATRIX         = 1 << 6,
    PARAM_OUTSHIFT       = 1 << 5,
    PARAM_QUANTSTEP      = 1 << 4,
    PARAM_FIR            = 1 << 3,
    PARAM_IIR            = 1 << 2,
    PARAM_HUFFOFFSET     = 1 << 1,
    PARAM_PRESENT        = 1 << 0,
};

typedef struct {
    uint16_t        blocksize;                  ///< number of PCM samples in current audio block
    uint8_t         quant_step_size[MAX_CHANNELS];  ///< left shift to apply to Huffman-decoded residuals

    MatrixParams    matrix_params;

    uint8_t         param_presence_flags;       ///< Bitmask of which parameter sets are conveyed in a decoding parameter block.
} DecodingParams;

typedef struct BestOffset {
    int32_t offset;
    int bitcount;
    int lsb_bits;
    int32_t min;
    int32_t max;
} BestOffset;

#define HUFF_OFFSET_MIN    (-16384)
#define HUFF_OFFSET_MAX    ( 16383)

/** Number of possible codebooks (counting "no codebooks") */
#define NUM_CODEBOOKS       4

typedef struct {
    AVCodecContext *avctx;

    int             num_substreams;         ///< Number of substreams contained within this stream.

    int             num_channels;   /**< Number of channels in major_scratch_buffer.
                                     *   Normal channels + noise channels. */

    int             coded_sample_fmt [2];   ///< sample format encoded for MLP
    int             coded_sample_rate[2];   ///< sample rate encoded for MLP
    int             coded_peak_bitrate;     ///< peak bitrate for this major sync header

    int             flags;                  ///< major sync info flags

    /* channel_meaning */
    int             substream_info;
    int             fs;
    int             wordlength;
    int             channel_occupancy;
    int             summary_info;

    int32_t        *inout_buffer;           ///< Pointer to data currently being read from lavc or written to bitstream.
    int32_t        *major_inout_buffer;     ///< Buffer with all in/out data for one entire major frame interval.
    int32_t        *write_buffer;           ///< Pointer to data currently being written to bitstream.
    int32_t        *sample_buffer;          ///< Pointer to current access unit samples.
    int32_t        *major_scratch_buffer;   ///< Scratch buffer big enough to fit all data for one entire major frame interval.
    int32_t        *last_frame;             ///< Pointer to last frame with data to encode.

    int32_t        *lpc_sample_buffer;

    unsigned int    major_number_of_frames;
    unsigned int    next_major_number_of_frames;

    unsigned int    major_frame_size;       ///< Number of samples in current major frame being encoded.
    unsigned int    next_major_frame_size;  ///< Counter of number of samples for next major frame.

    int32_t        *lossless_check_data;    ///< Array with lossless_check_data for each access unit.

    unsigned int   *max_output_bits;        ///< largest output bit-depth
    unsigned int   *frame_size;             ///< Array with number of samples/channel in each access unit.
    unsigned int    frame_index;            ///< Index of current frame being encoded.

    unsigned int    one_sample_buffer_size; ///< Number of samples*channel for one access unit.

    unsigned int    max_restart_interval;   ///< Max interval of access units in between two major frames.
    unsigned int    min_restart_interval;   ///< Min interval of access units in between two major frames.
    unsigned int    restart_intervals;      ///< Number of possible major frame sizes.

    uint16_t        timestamp;              ///< Timestamp of current access unit.
    uint16_t        dts;                    ///< Decoding timestamp of current access unit.

    uint8_t         channel_arrangement;    ///< channel arrangement for MLP streams

    uint8_t         ch_modifier_thd0;       ///< channel modifier for TrueHD stream 0
    uint8_t         ch_modifier_thd1;       ///< channel modifier for TrueHD stream 1
    uint8_t         ch_modifier_thd2;       ///< channel modifier for TrueHD stream 2

    unsigned int    seq_size  [MAJOR_HEADER_INTERVAL];
    unsigned int    seq_offset[MAJOR_HEADER_INTERVAL];
    unsigned int    sequence_size;

    ChannelParams  *channel_params;

    BestOffset      best_offset[MAJOR_HEADER_INTERVAL+1][MAX_CHANNELS][NUM_CODEBOOKS];

    DecodingParams *decoding_params;
    RestartHeader   restart_header [MAX_SUBSTREAMS];

    ChannelParams   major_channel_params[MAJOR_HEADER_INTERVAL+1][MAX_CHANNELS];       ///< ChannelParams to be written to bitstream.
    DecodingParams  major_decoding_params[MAJOR_HEADER_INTERVAL+1][MAX_SUBSTREAMS];    ///< DecodingParams to be written to bitstream.
    int             major_params_changed[MAJOR_HEADER_INTERVAL+1][MAX_SUBSTREAMS];     ///< params_changed to be written to bitstream.

    unsigned int    major_cur_subblock_index;
    unsigned int    major_filter_state_subblock;
    unsigned int    major_number_of_subblocks;

    BestOffset    (*cur_best_offset)[NUM_CODEBOOKS];
    ChannelParams  *cur_channel_params;
    DecodingParams *cur_decoding_params;
    RestartHeader  *cur_restart_header;

    AudioFrameQueue afq;

    /* Analysis stage. */
    unsigned int    starting_frame_index;
    unsigned int    number_of_frames;
    unsigned int    number_of_samples;
    unsigned int    number_of_subblocks;
    unsigned int    seq_index;              ///< Sequence index for high compression levels.

    const ChannelParams  *prev_channel_params;
    const DecodingParams *prev_decoding_params;

    ChannelParams  *seq_channel_params;
    DecodingParams *seq_decoding_params;

    unsigned int    max_codebook_search;

    LPCContext      lpc_ctx;
} MLPEncodeContext;

static ChannelParams   restart_channel_params[MAX_CHANNELS];
static DecodingParams  restart_decoding_params[MAX_SUBSTREAMS];
static const BestOffset restart_best_offset[NUM_CODEBOOKS] = {{0}};

#define SYNC_MAJOR      0xf8726f
#define MAJOR_SYNC_INFO_SIGNATURE   0xB752

#define SYNC_MLP        0xbb
#define SYNC_TRUEHD     0xba

/* must be set for DVD-A */
#define FLAGS_DVDA      0x4000
/* FIFO delay must be constant */
#define FLAGS_CONST     0x8000

#define SUBSTREAM_INFO_MAX_2_CHAN   0x01
#define SUBSTREAM_INFO_HIGH_RATE    0x02
#define SUBSTREAM_INFO_ALWAYS_SET   0x04
#define SUBSTREAM_INFO_2_SUBSTREAMS 0x08

/****************************************************************************
 ************ Functions that copy, clear, or compare parameters *************
 ****************************************************************************/

/** Compares two FilterParams structures and returns 1 if anything has
 *  changed. Returns 0 if they are both equal.
 */
static int compare_filter_params(const ChannelParams *prev_cp, const ChannelParams *cp, int filter)
{
    const FilterParams *prev = &prev_cp->filter_params[filter];
    const FilterParams *fp = &cp->filter_params[filter];
    int i;

    if (prev->order != fp->order)
        return 1;

    if (!prev->order)
        return 0;

    if (prev->shift != fp->shift)
        return 1;

    for (i = 0; i < fp->order; i++)
        if (prev_cp->coeff[filter][i] != cp->coeff[filter][i])
            return 1;

    return 0;
}

/** Compare two primitive matrices and returns 1 if anything has changed.
 *  Returns 0 if they are both equal.
 */
static int compare_matrix_params(MLPEncodeContext *ctx, const MatrixParams *prev, const MatrixParams *mp)
{
    RestartHeader *rh = ctx->cur_restart_header;
    unsigned int channel, mat;

    if (prev->count != mp->count)
        return 1;

    if (!prev->count)
        return 0;

    for (channel = rh->min_channel; channel <= rh->max_channel; channel++)
        if (prev->fbits[channel] != mp->fbits[channel])
            return 1;

    for (mat = 0; mat < mp->count; mat++) {
        if (prev->outch[mat] != mp->outch[mat])
            return 1;

        for (channel = 0; channel < ctx->num_channels; channel++)
            if (prev->coeff[mat][channel] != mp->coeff[mat][channel])
                return 1;
    }

    return 0;
}

/** Compares two DecodingParams and ChannelParams structures to decide if a
 *  new decoding params header has to be written.
 */
static int compare_decoding_params(MLPEncodeContext *ctx)
{
    const DecodingParams *prev = ctx->prev_decoding_params;
    DecodingParams *dp = ctx->cur_decoding_params;
    const MatrixParams *prev_mp = &prev->matrix_params;
    MatrixParams *mp = &dp->matrix_params;
    RestartHeader  *rh = ctx->cur_restart_header;
    unsigned int ch;
    int retval = 0;

    if (prev->param_presence_flags != dp->param_presence_flags)
        retval |= PARAM_PRESENCE_FLAGS;

    if (prev->blocksize != dp->blocksize)
        retval |= PARAM_BLOCKSIZE;

    if (compare_matrix_params(ctx, prev_mp, mp))
        retval |= PARAM_MATRIX;

    for (ch = 0; ch <= rh->max_matrix_channel; ch++)
        if (prev_mp->shift[ch] != mp->shift[ch]) {
            retval |= PARAM_OUTSHIFT;
            break;
        }

    for (ch = 0; ch <= rh->max_channel; ch++)
        if (prev->quant_step_size[ch] != dp->quant_step_size[ch]) {
            retval |= PARAM_QUANTSTEP;
            break;
        }

    for (ch = rh->min_channel; ch <= rh->max_channel; ch++) {
        const ChannelParams *prev_cp = &ctx->prev_channel_params[ch];
        ChannelParams *cp = &ctx->cur_channel_params[ch];

        if (!(retval & PARAM_FIR) &&
            compare_filter_params(prev_cp, cp, FIR))
            retval |= PARAM_FIR;

        if (!(retval & PARAM_IIR) &&
            compare_filter_params(prev_cp, cp, IIR))
            retval |= PARAM_IIR;

        if (prev_cp->huff_offset != cp->huff_offset)
            retval |= PARAM_HUFFOFFSET;

        if (prev_cp->codebook    != cp->codebook  ||
            prev_cp->huff_lsbs   != cp->huff_lsbs  )
            retval |= 0x1;
    }

    return retval;
}

static void copy_filter_params(ChannelParams *dst_cp, ChannelParams *src_cp, int filter)
{
    FilterParams *dst = &dst_cp->filter_params[filter];
    FilterParams *src = &src_cp->filter_params[filter];
    unsigned int order;

    dst->order = src->order;

    if (dst->order) {
        dst->shift = src->shift;

        dst->coeff_shift = src->coeff_shift;
        dst->coeff_bits = src->coeff_bits;
    }

    for (order = 0; order < dst->order; order++)
        dst_cp->coeff[filter][order] = src_cp->coeff[filter][order];
}

static void copy_matrix_params(MatrixParams *dst, MatrixParams *src)
{
    dst->count = src->count;

    if (dst->count) {
        unsigned int channel, count;

        for (channel = 0; channel < MAX_CHANNELS; channel++) {

            dst->fbits[channel] = src->fbits[channel];
            dst->shift[channel] = src->shift[channel];

            for (count = 0; count < MAX_MATRICES; count++)
                dst->coeff[count][channel] = src->coeff[count][channel];
        }

        for (count = 0; count < MAX_MATRICES; count++)
            dst->outch[count] = src->outch[count];
    }
}

static void copy_restart_frame_params(MLPEncodeContext *ctx,
                                      unsigned int substr)
{
    unsigned int index;

    for (index = 0; index < ctx->number_of_subblocks; index++) {
        DecodingParams *dp = ctx->seq_decoding_params + index*(ctx->num_substreams) + substr;
        unsigned int channel;

        copy_matrix_params(&dp->matrix_params, &ctx->cur_decoding_params->matrix_params);

        for (channel = 0; channel < ctx->avctx->channels; channel++) {
            ChannelParams *cp = ctx->seq_channel_params + index*(ctx->avctx->channels) + channel;
            unsigned int filter;

            dp->quant_step_size[channel] = ctx->cur_decoding_params->quant_step_size[channel];
            dp->matrix_params.shift[channel] = ctx->cur_decoding_params->matrix_params.shift[channel];

            if (index)
                for (filter = 0; filter < NUM_FILTERS; filter++)
                    copy_filter_params(cp, &ctx->cur_channel_params[channel], filter);
        }
    }
}

/** Clears a DecodingParams struct the way it should be after a restart header. */
static void clear_decoding_params(DecodingParams decoding_params[MAX_SUBSTREAMS], int num_substreams)
{
    for (unsigned substr = 0; substr < num_substreams; substr++) {
        DecodingParams *dp = &decoding_params[substr];

        dp->param_presence_flags   = 0xff;
        dp->blocksize              = 8;

        memset(&dp->matrix_params , 0, sizeof(MatrixParams       ));
        memset(dp->quant_step_size, 0, sizeof(dp->quant_step_size));
    }
}

/** Clears a ChannelParams struct the way it should be after a restart header. */
static void clear_channel_params(ChannelParams channel_params[MAX_CHANNELS], int nb_channels)
{
    for (unsigned channel = 0; channel < nb_channels; channel++) {
        ChannelParams *cp = &channel_params[channel];

        memset(&cp->filter_params, 0, sizeof(cp->filter_params));

        /* Default audio coding is 24-bit raw PCM. */
        cp->huff_offset      =  0;
        cp->codebook         =  0;
        cp->huff_lsbs        = 24;
    }
}

/** Sets default vales in our encoder for a DecodingParams struct. */
static void default_decoding_params(MLPEncodeContext *ctx,
     DecodingParams decoding_params[MAX_SUBSTREAMS])
{
    unsigned int substr;

    clear_decoding_params(decoding_params, ctx->num_substreams);

    for (substr = 0; substr < ctx->num_substreams; substr++) {
        DecodingParams *dp = &decoding_params[substr];
        uint8_t param_presence_flags = 0;

        param_presence_flags |= PARAM_BLOCKSIZE;
        param_presence_flags |= PARAM_MATRIX;
        param_presence_flags |= PARAM_OUTSHIFT;
        param_presence_flags |= PARAM_QUANTSTEP;
        param_presence_flags |= PARAM_FIR;
/*      param_presence_flags |= PARAM_IIR; */
        param_presence_flags |= PARAM_HUFFOFFSET;
        param_presence_flags |= PARAM_PRESENT;

        dp->param_presence_flags = param_presence_flags;
    }
}

/****************************************************************************/

/** Calculates the smallest number of bits it takes to encode a given signed
 *  value in two's complement.
 */
static int inline number_sbits(int number)
{
    if (number < -1)
        number++;

    return av_log2(FFABS(number)) + 1 + !!number;
}

enum InputBitDepth {
    BITS_16,
    BITS_20,
    BITS_24,
};

static int mlp_peak_bitrate(int peak_bitrate, int sample_rate)
{
    return ((peak_bitrate << 4) - 8) / sample_rate;
}

static av_cold void mlp_encode_init_static(void)
{
    clear_channel_params (restart_channel_params,  MAX_CHANNELS);
    clear_decoding_params(restart_decoding_params, MAX_SUBSTREAMS);
    ff_mlp_init_crc();
}

static av_cold int mlp_encode_init(AVCodecContext *avctx)
{
    static AVOnce init_static_once = AV_ONCE_INIT;
    MLPEncodeContext *ctx = avctx->priv_data;
    unsigned int substr, index;
    unsigned int sum = 0;
    unsigned int size;
    int ret;

    ctx->avctx = avctx;

    switch (avctx->sample_rate) {
    case 44100 << 0:
        avctx->frame_size         = 40  << 0;
        ctx->coded_sample_rate[0] = 0x08 + 0;
        ctx->fs                   = 0x08 + 1;
        break;
    case 44100 << 1:
        avctx->frame_size         = 40  << 1;
        ctx->coded_sample_rate[0] = 0x08 + 1;
        ctx->fs                   = 0x0C + 1;
        break;
    case 44100 << 2:
        ctx->substream_info      |= SUBSTREAM_INFO_HIGH_RATE;
        avctx->frame_size         = 40  << 2;
        ctx->coded_sample_rate[0] = 0x08 + 2;
        ctx->fs                   = 0x10 + 1;
        break;
    case 48000 << 0:
        avctx->frame_size         = 40  << 0;
        ctx->coded_sample_rate[0] = 0x00 + 0;
        ctx->fs                   = 0x08 + 2;
        break;
    case 48000 << 1:
        avctx->frame_size         = 40  << 1;
        ctx->coded_sample_rate[0] = 0x00 + 1;
        ctx->fs                   = 0x0C + 2;
        break;
    case 48000 << 2:
        ctx->substream_info      |= SUBSTREAM_INFO_HIGH_RATE;
        avctx->frame_size         = 40  << 2;
        ctx->coded_sample_rate[0] = 0x00 + 2;
        ctx->fs                   = 0x10 + 2;
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "Unsupported sample rate %d. Supported "
                            "sample rates are 44100, 88200, 176400, 48000, "
                            "96000, and 192000.\n", avctx->sample_rate);
        return AVERROR(EINVAL);
    }
    ctx->coded_sample_rate[1] = -1 & 0xf;

    /* TODO Keep count of bitrate and calculate real value. */
    ctx->coded_peak_bitrate = mlp_peak_bitrate(9600000, avctx->sample_rate);

    /* TODO support more channels. */
    if (avctx->channels > 2) {
        av_log(avctx, AV_LOG_WARNING,
               "Only mono and stereo are supported at the moment.\n");
    }

    ctx->substream_info |= SUBSTREAM_INFO_ALWAYS_SET;
    if (avctx->channels <= 2) {
        ctx->substream_info |= SUBSTREAM_INFO_MAX_2_CHAN;
    }

    switch (avctx->sample_fmt) {
    case AV_SAMPLE_FMT_S16:
        ctx->coded_sample_fmt[0] = BITS_16;
        ctx->wordlength = 16;
        avctx->bits_per_raw_sample = 16;
        break;
    /* TODO 20 bits: */
    case AV_SAMPLE_FMT_S32:
        ctx->coded_sample_fmt[0] = BITS_24;
        ctx->wordlength = 24;
        avctx->bits_per_raw_sample = 24;
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "Sample format not supported. "
               "Only 16- and 24-bit samples are supported.\n");
        return AVERROR(EINVAL);
    }
    ctx->coded_sample_fmt[1] = -1 & 0xf;

    ctx->dts = -avctx->frame_size;

    ctx->num_channels = avctx->channels + 2; /* +2 noise channels */
    ctx->one_sample_buffer_size = avctx->frame_size
                                * ctx->num_channels;
    /* TODO Let user pass major header interval as parameter. */
    ctx->max_restart_interval = MAJOR_HEADER_INTERVAL;

    ctx->max_codebook_search = 3;
    ctx->min_restart_interval = MAJOR_HEADER_INTERVAL;
    ctx->restart_intervals = ctx->max_restart_interval / ctx->min_restart_interval;

    /* TODO Let user pass parameters for LPC filter. */

    size = avctx->frame_size * ctx->max_restart_interval;

    ctx->lpc_sample_buffer = av_malloc_array(size, sizeof(int32_t));
    if (!ctx->lpc_sample_buffer) {
        av_log(avctx, AV_LOG_ERROR,
               "Not enough memory for buffering samples.\n");
        return AVERROR(ENOMEM);
    }

    size = ctx->one_sample_buffer_size * ctx->max_restart_interval;

    ctx->major_scratch_buffer = av_malloc_array(size, sizeof(int32_t));
    if (!ctx->major_scratch_buffer) {
        av_log(avctx, AV_LOG_ERROR,
               "Not enough memory for buffering samples.\n");
        return AVERROR(ENOMEM);
    }

    ctx->major_inout_buffer = av_malloc_array(size, sizeof(int32_t));
    if (!ctx->major_inout_buffer) {
        av_log(avctx, AV_LOG_ERROR,
               "Not enough memory for buffering samples.\n");
        return AVERROR(ENOMEM);
    }

    ctx->num_substreams = 1; // TODO: change this after adding multi-channel support for TrueHD

    if (ctx->avctx->codec_id == AV_CODEC_ID_MLP) {
        /* MLP */
        switch(avctx->channel_layout) {
        case AV_CH_LAYOUT_MONO:
            ctx->channel_arrangement = 0; break;
        case AV_CH_LAYOUT_STEREO:
            ctx->channel_arrangement = 1; break;
        case AV_CH_LAYOUT_2_1:
            ctx->channel_arrangement = 2; break;
        case AV_CH_LAYOUT_QUAD:
            ctx->channel_arrangement = 3; break;
        case AV_CH_LAYOUT_2POINT1:
            ctx->channel_arrangement = 4; break;
        case AV_CH_LAYOUT_SURROUND:
            ctx->channel_arrangement = 7; break;
        case AV_CH_LAYOUT_4POINT0:
            ctx->channel_arrangement = 8; break;
        case AV_CH_LAYOUT_5POINT0_BACK:
            ctx->channel_arrangement = 9; break;
        case AV_CH_LAYOUT_3POINT1:
            ctx->channel_arrangement = 10; break;
        case AV_CH_LAYOUT_4POINT1:
            ctx->channel_arrangement = 11; break;
        case AV_CH_LAYOUT_5POINT1_BACK:
            ctx->channel_arrangement = 12; break;
        default:
            av_log(avctx, AV_LOG_ERROR, "Unsupported channel arrangement\n");
            return AVERROR(EINVAL);
        }
        ctx->flags = FLAGS_DVDA;
        ctx->channel_occupancy = ff_mlp_ch_info[ctx->channel_arrangement].channel_occupancy;
        ctx->summary_info      = ff_mlp_ch_info[ctx->channel_arrangement].summary_info     ;
    } else {
        /* TrueHD */
        switch(avctx->channel_layout) {
        case AV_CH_LAYOUT_STEREO:
            ctx->ch_modifier_thd0    = 0;
            ctx->ch_modifier_thd1    = 0;
            ctx->ch_modifier_thd2    = 0;
            ctx->channel_arrangement = 1;
            break;
        case AV_CH_LAYOUT_5POINT0_BACK:
            ctx->ch_modifier_thd0    = 1;
            ctx->ch_modifier_thd1    = 1;
            ctx->ch_modifier_thd2    = 1;
            ctx->channel_arrangement = 11;
            break;
        case AV_CH_LAYOUT_5POINT1_BACK:
            ctx->ch_modifier_thd0    = 2;
            ctx->ch_modifier_thd1    = 1;
            ctx->ch_modifier_thd2    = 2;
            ctx->channel_arrangement = 15;
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "Unsupported channel arrangement\n");
            return AVERROR(EINVAL);
        }
        ctx->flags = 0;
        ctx->channel_occupancy = 0;
        ctx->summary_info = 0;
    }

    size = sizeof(unsigned int) * ctx->max_restart_interval;

    ctx->frame_size = av_malloc(size);
    if (!ctx->frame_size)
        return AVERROR(ENOMEM);

    ctx->max_output_bits = av_malloc(size);
    if (!ctx->max_output_bits)
        return AVERROR(ENOMEM);

    size = sizeof(int32_t)
         * ctx->num_substreams * ctx->max_restart_interval;

    ctx->lossless_check_data = av_malloc(size);
    if (!ctx->lossless_check_data)
        return AVERROR(ENOMEM);

    for (index = 0; index < ctx->restart_intervals; index++) {
        ctx->seq_offset[index] = sum;
        ctx->seq_size  [index] = ((index + 1) * ctx->min_restart_interval) + 1;
        sum += ctx->seq_size[index];
    }
    ctx->sequence_size = sum;
    size = sizeof(ChannelParams)
         * ctx->restart_intervals * ctx->sequence_size * ctx->avctx->channels;
    ctx->channel_params = av_malloc(size);
    if (!ctx->channel_params) {
        av_log(avctx, AV_LOG_ERROR,
               "Not enough memory for analysis context.\n");
        return AVERROR(ENOMEM);
    }

    size = sizeof(DecodingParams)
         * ctx->restart_intervals * ctx->sequence_size * ctx->num_substreams;
    ctx->decoding_params = av_malloc(size);
    if (!ctx->decoding_params) {
        av_log(avctx, AV_LOG_ERROR,
               "Not enough memory for analysis context.\n");
        return AVERROR(ENOMEM);
    }

    for (substr = 0; substr < ctx->num_substreams; substr++) {
        RestartHeader  *rh = &ctx->restart_header [substr];

        /* TODO see if noisegen_seed is really worth it. */
        rh->noisegen_seed      = 0;

        rh->min_channel        = 0;
        rh->max_channel        = avctx->channels - 1;
        /* FIXME: this works for 1 and 2 channels, but check for more */
        rh->max_matrix_channel = rh->max_channel;
    }

    if ((ret = ff_lpc_init(&ctx->lpc_ctx, ctx->number_of_samples,
                    MLP_MAX_LPC_ORDER, FF_LPC_TYPE_LEVINSON)) < 0) {
        av_log(avctx, AV_LOG_ERROR,
               "Not enough memory for LPC context.\n");
        return ret;
    }

    ff_af_queue_init(avctx, &ctx->afq);

    ff_thread_once(&init_static_once, mlp_encode_init_static);

    return 0;
}

/****************************************************************************
 ****************** Functions that write to the bitstream *******************
 ****************************************************************************/

/** Writes a major sync header to the bitstream. */
static void write_major_sync(MLPEncodeContext *ctx, uint8_t *buf, int buf_size)
{
    PutBitContext pb;

    init_put_bits(&pb, buf, buf_size);

    put_bits(&pb, 24, SYNC_MAJOR               );

    if (ctx->avctx->codec_id == AV_CODEC_ID_MLP) {
        put_bits(&pb,  8, SYNC_MLP                 );
        put_bits(&pb,  4, ctx->coded_sample_fmt [0]);
        put_bits(&pb,  4, ctx->coded_sample_fmt [1]);
        put_bits(&pb,  4, ctx->coded_sample_rate[0]);
        put_bits(&pb,  4, ctx->coded_sample_rate[1]);
        put_bits(&pb,  4, 0                        ); /* ignored */
        put_bits(&pb,  4, 0                        ); /* multi_channel_type */
        put_bits(&pb,  3, 0                        ); /* ignored */
        put_bits(&pb,  5, ctx->channel_arrangement );
    } else if (ctx->avctx->codec_id == AV_CODEC_ID_TRUEHD) {
        put_bits(&pb,  8, SYNC_TRUEHD              );
        put_bits(&pb,  4, ctx->coded_sample_rate[0]);
        put_bits(&pb,  4, 0                        ); /* ignored */
        put_bits(&pb,  2, ctx->ch_modifier_thd0    );
        put_bits(&pb,  2, ctx->ch_modifier_thd1    );
        put_bits(&pb,  5, ctx->channel_arrangement );
        put_bits(&pb,  2, ctx->ch_modifier_thd2    );
        put_bits(&pb, 13, ctx->channel_arrangement );
    }

    put_bits(&pb, 16, MAJOR_SYNC_INFO_SIGNATURE);
    put_bits(&pb, 16, ctx->flags               );
    put_bits(&pb, 16, 0                        ); /* ignored */
    put_bits(&pb,  1, 1                        ); /* is_vbr */
    put_bits(&pb, 15, ctx->coded_peak_bitrate  );
    put_bits(&pb,  4, 1                        ); /* num_substreams */
    put_bits(&pb,  4, 0x1                      ); /* ignored */

    /* channel_meaning */
    put_bits(&pb,  8, ctx->substream_info      );
    put_bits(&pb,  5, ctx->fs                  );
    put_bits(&pb,  5, ctx->wordlength          );
    put_bits(&pb,  6, ctx->channel_occupancy   );
    put_bits(&pb,  3, 0                        ); /* ignored */
    put_bits(&pb, 10, 0                        ); /* speaker_layout */
    put_bits(&pb,  3, 0                        ); /* copy_protection */
    put_bits(&pb, 16, 0x8080                   ); /* ignored */
    put_bits(&pb,  7, 0                        ); /* ignored */
    put_bits(&pb,  4, 0                        ); /* source_format */
    put_bits(&pb,  5, ctx->summary_info        );

    flush_put_bits(&pb);

    AV_WL16(buf+26, ff_mlp_checksum16(buf, 26));
}

/** Writes a restart header to the bitstream. Damaged streams can start being
 *  decoded losslessly again after such a header and the subsequent decoding
 *  params header.
 */
static void write_restart_header(MLPEncodeContext *ctx, PutBitContext *pb)
{
    RestartHeader *rh = ctx->cur_restart_header;
    uint8_t lossless_check = xor_32_to_8(rh->lossless_check_data);
    unsigned int start_count = put_bits_count(pb);
    PutBitContext tmpb;
    uint8_t checksum;
    unsigned int ch;

    put_bits(pb, 14, 0x31ea                ); /* TODO 0x31eb */
    put_bits(pb, 16, ctx->timestamp        );
    put_bits(pb,  4, rh->min_channel       );
    put_bits(pb,  4, rh->max_channel       );
    put_bits(pb,  4, rh->max_matrix_channel);
    put_bits(pb,  4, rh->noise_shift       );
    put_bits(pb, 23, rh->noisegen_seed     );
    put_bits(pb,  4, 0                     ); /* TODO max_shift */
    put_bits(pb,  5, rh->max_huff_lsbs     );
    put_bits(pb,  5, rh->max_output_bits   );
    put_bits(pb,  5, rh->max_output_bits   );
    put_bits(pb,  1, rh->data_check_present);
    put_bits(pb,  8, lossless_check        );
    put_bits(pb, 16, 0                     ); /* ignored */

    for (ch = 0; ch <= rh->max_matrix_channel; ch++)
        put_bits(pb, 6, ch);

    /* Data must be flushed for the checksum to be correct. */
    tmpb = *pb;
    flush_put_bits(&tmpb);

    checksum = ff_mlp_restart_checksum(pb->buf, put_bits_count(pb) - start_count);

    put_bits(pb,  8, checksum);
}

/** Writes matrix params for all primitive matrices to the bitstream. */
static void write_matrix_params(MLPEncodeContext *ctx, PutBitContext *pb)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    MatrixParams *mp = &dp->matrix_params;
    unsigned int mat;

    put_bits(pb, 4, mp->count);

    for (mat = 0; mat < mp->count; mat++) {
        unsigned int channel;

        put_bits(pb, 4, mp->outch[mat]); /* matrix_out_ch */
        put_bits(pb, 4, mp->fbits[mat]);
        put_bits(pb, 1, 0             ); /* lsb_bypass */

        for (channel = 0; channel < ctx->num_channels; channel++) {
            int32_t coeff = mp->coeff[mat][channel];

            if (coeff) {
                put_bits(pb, 1, 1);

                coeff >>= 14 - mp->fbits[mat];

                put_sbits(pb, mp->fbits[mat] + 2, coeff);
            } else {
                put_bits(pb, 1, 0);
            }
        }
    }
}

/** Writes filter parameters for one filter to the bitstream. */
static void write_filter_params(MLPEncodeContext *ctx, PutBitContext *pb,
                                unsigned int channel, unsigned int filter)
{
    FilterParams *fp = &ctx->cur_channel_params[channel].filter_params[filter];

    put_bits(pb, 4, fp->order);

    if (fp->order > 0) {
        int i;
        int32_t *fcoeff = ctx->cur_channel_params[channel].coeff[filter];

        put_bits(pb, 4, fp->shift      );
        put_bits(pb, 5, fp->coeff_bits );
        put_bits(pb, 3, fp->coeff_shift);

        for (i = 0; i < fp->order; i++) {
            put_sbits(pb, fp->coeff_bits, fcoeff[i] >> fp->coeff_shift);
        }

        /* TODO state data for IIR filter. */
        put_bits(pb, 1, 0);
    }
}

/** Writes decoding parameters to the bitstream. These change very often,
 *  usually at almost every frame.
 */
static void write_decoding_params(MLPEncodeContext *ctx, PutBitContext *pb,
                                  int params_changed)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    RestartHeader  *rh = ctx->cur_restart_header;
    MatrixParams *mp = &dp->matrix_params;
    unsigned int ch;

    if (dp->param_presence_flags != PARAMS_DEFAULT &&
        params_changed & PARAM_PRESENCE_FLAGS) {
        put_bits(pb, 1, 1);
        put_bits(pb, 8, dp->param_presence_flags);
    } else {
        put_bits(pb, 1, 0);
    }

    if (dp->param_presence_flags & PARAM_BLOCKSIZE) {
        if (params_changed       & PARAM_BLOCKSIZE) {
            put_bits(pb, 1, 1);
            put_bits(pb, 9, dp->blocksize);
        } else {
            put_bits(pb, 1, 0);
        }
    }

    if (dp->param_presence_flags & PARAM_MATRIX) {
        if (params_changed       & PARAM_MATRIX) {
            put_bits(pb, 1, 1);
            write_matrix_params(ctx, pb);
        } else {
            put_bits(pb, 1, 0);
        }
    }

    if (dp->param_presence_flags & PARAM_OUTSHIFT) {
        if (params_changed       & PARAM_OUTSHIFT) {
            put_bits(pb, 1, 1);
            for (ch = 0; ch <= rh->max_matrix_channel; ch++)
                put_sbits(pb, 4, mp->shift[ch]);
        } else {
            put_bits(pb, 1, 0);
        }
    }

    if (dp->param_presence_flags & PARAM_QUANTSTEP) {
        if (params_changed       & PARAM_QUANTSTEP) {
            put_bits(pb, 1, 1);
            for (ch = 0; ch <= rh->max_channel; ch++)
                put_bits(pb, 4, dp->quant_step_size[ch]);
        } else {
            put_bits(pb, 1, 0);
        }
    }

    for (ch = rh->min_channel; ch <= rh->max_channel; ch++) {
        ChannelParams *cp = &ctx->cur_channel_params[ch];

        if (dp->param_presence_flags & 0xF) {
            put_bits(pb, 1, 1);

            if (dp->param_presence_flags & PARAM_FIR) {
                if (params_changed       & PARAM_FIR) {
                    put_bits(pb, 1, 1);
                    write_filter_params(ctx, pb, ch, FIR);
                } else {
                    put_bits(pb, 1, 0);
                }
            }

            if (dp->param_presence_flags & PARAM_IIR) {
                if (params_changed       & PARAM_IIR) {
                    put_bits(pb, 1, 1);
                    write_filter_params(ctx, pb, ch, IIR);
                } else {
                    put_bits(pb, 1, 0);
                }
            }

            if (dp->param_presence_flags & PARAM_HUFFOFFSET) {
                if (params_changed       & PARAM_HUFFOFFSET) {
                    put_bits (pb,  1, 1);
                    put_sbits(pb, 15, cp->huff_offset);
                } else {
                    put_bits(pb, 1, 0);
                }
            }
            if (cp->codebook > 0 && cp->huff_lsbs > 24) {
                av_log(ctx->avctx, AV_LOG_ERROR, "Invalid Huff LSBs\n");
            }

            put_bits(pb, 2, cp->codebook );
            put_bits(pb, 5, cp->huff_lsbs);
        } else {
            put_bits(pb, 1, 0);
        }
    }
}

/** Writes the residuals to the bitstream. That is, the VLC codes from the
 *  codebooks (if any is used), and then the residual.
 */
static void write_block_data(MLPEncodeContext *ctx, PutBitContext *pb)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    RestartHeader  *rh = ctx->cur_restart_header;
    int32_t *sample_buffer = ctx->write_buffer;
    int32_t sign_huff_offset[MAX_CHANNELS];
    int codebook_index      [MAX_CHANNELS];
    int lsb_bits            [MAX_CHANNELS];
    unsigned int i, ch;

    for (ch = rh->min_channel; ch <= rh->max_channel; ch++) {
        ChannelParams *cp = &ctx->cur_channel_params[ch];
        int sign_shift;

        lsb_bits        [ch] = cp->huff_lsbs - dp->quant_step_size[ch];
        codebook_index  [ch] = cp->codebook  - 1;
        sign_huff_offset[ch] = cp->huff_offset;

        sign_shift = lsb_bits[ch] + (cp->codebook ? 2 - cp->codebook : -1);

        if (cp->codebook > 0)
            sign_huff_offset[ch] -= 7 << lsb_bits[ch];

        /* Unsign if needed. */
        if (sign_shift >= 0)
            sign_huff_offset[ch] -= 1 << sign_shift;
    }

    for (i = 0; i < dp->blocksize; i++) {
        for (ch = rh->min_channel; ch <= rh->max_channel; ch++) {
            int32_t sample = *sample_buffer++ >> dp->quant_step_size[ch];
            sample -= sign_huff_offset[ch];

            if (codebook_index[ch] >= 0) {
                int vlc = sample >> lsb_bits[ch];
                put_bits(pb, ff_mlp_huffman_tables[codebook_index[ch]][vlc][1],
                             ff_mlp_huffman_tables[codebook_index[ch]][vlc][0]);
            }

            put_sbits(pb, lsb_bits[ch], sample);
        }
        sample_buffer += 2; /* noise channels */
    }

    ctx->write_buffer = sample_buffer;
}

/** Writes the substreams data to the bitstream. */
static uint8_t *write_substrs(MLPEncodeContext *ctx, uint8_t *buf, int buf_size,
                              int restart_frame,
                              uint16_t substream_data_len[MAX_SUBSTREAMS])
{
    int32_t *lossless_check_data = ctx->lossless_check_data;
    unsigned int substr;
    int end = 0;

    lossless_check_data += ctx->frame_index * ctx->num_substreams;

    for (substr = 0; substr < ctx->num_substreams; substr++) {
        unsigned int cur_subblock_index = ctx->major_cur_subblock_index;
        unsigned int num_subblocks = ctx->major_filter_state_subblock;
        unsigned int subblock;
        RestartHeader  *rh = &ctx->restart_header [substr];
        int substr_restart_frame = restart_frame;
        uint8_t parity, checksum;
        PutBitContext pb;
        int params_changed;

        ctx->cur_restart_header = rh;

        init_put_bits(&pb, buf, buf_size);

        for (subblock = 0; subblock <= num_subblocks; subblock++) {
            unsigned int subblock_index;

            subblock_index = cur_subblock_index++;

            ctx->cur_decoding_params = &ctx->major_decoding_params[subblock_index][substr];
            ctx->cur_channel_params = ctx->major_channel_params[subblock_index];

            params_changed = ctx->major_params_changed[subblock_index][substr];

            if (substr_restart_frame || params_changed) {
                put_bits(&pb, 1, 1);

                if (substr_restart_frame) {
                    put_bits(&pb, 1, 1);

                    write_restart_header(ctx, &pb);
                    rh->lossless_check_data = 0;
                } else {
                    put_bits(&pb, 1, 0);
                }

                write_decoding_params(ctx, &pb, params_changed);
            } else {
                put_bits(&pb, 1, 0);
            }

            write_block_data(ctx, &pb);

            put_bits(&pb, 1, !substr_restart_frame);

            substr_restart_frame = 0;
        }

        put_bits(&pb, (-put_bits_count(&pb)) & 15, 0);

        rh->lossless_check_data ^= *lossless_check_data++;

        if (ctx->last_frame == ctx->inout_buffer) {
            /* TODO find a sample and implement shorten_by. */
            put_bits(&pb, 32, END_OF_STREAM);
        }

        /* Data must be flushed for the checksum and parity to be correct;
         * notice that we already are word-aligned here. */
        flush_put_bits(&pb);

        parity   = ff_mlp_calculate_parity(buf, put_bytes_output(&pb)) ^ 0xa9;
        checksum = ff_mlp_checksum8       (buf, put_bytes_output(&pb));

        put_bits(&pb, 8, parity  );
        put_bits(&pb, 8, checksum);

        flush_put_bits(&pb);

        end += put_bytes_output(&pb);
        substream_data_len[substr] = end;

        buf += put_bytes_output(&pb);
    }

    ctx->major_cur_subblock_index += ctx->major_filter_state_subblock + 1;
    ctx->major_filter_state_subblock = 0;

    return buf;
}

/** Writes the access unit and substream headers to the bitstream. */
static void write_frame_headers(MLPEncodeContext *ctx, uint8_t *frame_header,
                                uint8_t *substream_headers, unsigned int length,
                                int restart_frame,
                                uint16_t substream_data_len[MAX_SUBSTREAMS])
{
    uint16_t access_unit_header = 0;
    uint16_t parity_nibble = 0;
    unsigned int substr;

    parity_nibble  = ctx->dts;
    parity_nibble ^= length;

    for (substr = 0; substr < ctx->num_substreams; substr++) {
        uint16_t substr_hdr = 0;

        substr_hdr |= (0 << 15); /* extraword */
        substr_hdr |= (!restart_frame << 14); /* !restart_frame */
        substr_hdr |= (1 << 13); /* checkdata */
        substr_hdr |= (0 << 12); /* ??? */
        substr_hdr |= (substream_data_len[substr] / 2) & 0x0FFF;

        AV_WB16(substream_headers, substr_hdr);

        parity_nibble ^= *substream_headers++;
        parity_nibble ^= *substream_headers++;
    }

    parity_nibble ^= parity_nibble >> 8;
    parity_nibble ^= parity_nibble >> 4;
    parity_nibble &= 0xF;

    access_unit_header |= (parity_nibble ^ 0xF) << 12;
    access_unit_header |= length & 0xFFF;

    AV_WB16(frame_header  , access_unit_header);
    AV_WB16(frame_header+2, ctx->dts          );
}

/** Writes an entire access unit to the bitstream. */
static unsigned int write_access_unit(MLPEncodeContext *ctx, uint8_t *buf,
                                      int buf_size, int restart_frame)
{
    uint16_t substream_data_len[MAX_SUBSTREAMS];
    uint8_t *buf1, *buf0 = buf;
    unsigned int substr;
    int total_length;

    if (buf_size < 4)
        return AVERROR(EINVAL);

    /* Frame header will be written at the end. */
    buf      += 4;
    buf_size -= 4;

    if (restart_frame) {
        if (buf_size < 28)
            return AVERROR(EINVAL);
        write_major_sync(ctx, buf, buf_size);
        buf      += 28;
        buf_size -= 28;
    }

    buf1 = buf;

    /* Substream headers will be written at the end. */
    for (substr = 0; substr < ctx->num_substreams; substr++) {
        buf      += 2;
        buf_size -= 2;
    }

    buf = write_substrs(ctx, buf, buf_size, restart_frame, substream_data_len);

    total_length = buf - buf0;

    write_frame_headers(ctx, buf0, buf1, total_length / 2, restart_frame, substream_data_len);

    return total_length;
}

/****************************************************************************
 ****************** Functions that input data to context ********************
 ****************************************************************************/

/** Inputs data from the samples passed by lavc into the context, shifts them
 *  appropriately depending on the bit-depth, and calculates the
 *  lossless_check_data that will be written to the restart header.
 */
static void input_data_internal(MLPEncodeContext *ctx, const uint8_t *samples,
                                int is24)
{
    int32_t *lossless_check_data = ctx->lossless_check_data;
    const int32_t *samples_32 = (const int32_t *) samples;
    const int16_t *samples_16 = (const int16_t *) samples;
    unsigned int substr;

    lossless_check_data += ctx->frame_index * ctx->num_substreams;

    for (substr = 0; substr < ctx->num_substreams; substr++) {
        RestartHeader  *rh = &ctx->restart_header [substr];
        int32_t *sample_buffer = ctx->inout_buffer;
        int32_t temp_lossless_check_data = 0;
        uint32_t greatest = 0;
        unsigned int channel;
        int i;

        for (i = 0; i < ctx->frame_size[ctx->frame_index]; i++) {
            for (channel = 0; channel <= rh->max_channel; channel++) {
                uint32_t abs_sample;
                int32_t sample;

                sample = is24 ? *samples_32++ >> 8 : *samples_16++ * 256;

                /* TODO Find out if number_sbits can be used for negative values. */
                abs_sample = FFABS(sample);
                if (greatest < abs_sample)
                    greatest = abs_sample;

                temp_lossless_check_data ^= (sample & 0x00ffffff) << channel;
                *sample_buffer++ = sample;
            }

            sample_buffer += 2; /* noise channels */
        }

        ctx->max_output_bits[ctx->frame_index] = number_sbits(greatest);

        *lossless_check_data++ = temp_lossless_check_data;
    }
}

/** Wrapper function for inputting data in two different bit-depths. */
static void input_data(MLPEncodeContext *ctx, void *samples)
{
    if (ctx->avctx->sample_fmt == AV_SAMPLE_FMT_S32)
        input_data_internal(ctx, samples, 1);
    else
        input_data_internal(ctx, samples, 0);
}

static void input_to_sample_buffer(MLPEncodeContext *ctx)
{
    int32_t *sample_buffer = ctx->sample_buffer;
    unsigned int index;

    for (index = 0; index < ctx->number_of_frames; index++) {
        unsigned int cur_index = (ctx->starting_frame_index + index) % ctx->max_restart_interval;
        int32_t *input_buffer = ctx->inout_buffer + cur_index * ctx->one_sample_buffer_size;
        unsigned int i, channel;

        for (i = 0; i < ctx->frame_size[cur_index]; i++) {
            for (channel = 0; channel < ctx->avctx->channels; channel++)
                *sample_buffer++ = *input_buffer++;
            sample_buffer += 2; /* noise_channels */
            input_buffer += 2; /* noise_channels */
        }
    }
}

/****************************************************************************
 ********* Functions that analyze the data and set the parameters ***********
 ****************************************************************************/

/** Counts the number of trailing zeroes in a value */
static int number_trailing_zeroes(int32_t sample)
{
    int bits;

    for (bits = 0; bits < 24 && !(sample & (1<<bits)); bits++);

    /* All samples are 0. TODO Return previous quant_step_size to avoid
     * writing a new header. */
    if (bits == 24)
        return 0;

    return bits;
}

/** Determines how many bits are zero at the end of all samples so they can be
 *  shifted out.
 */
static void determine_quant_step_size(MLPEncodeContext *ctx)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    RestartHeader  *rh = ctx->cur_restart_header;
    MatrixParams *mp = &dp->matrix_params;
    int32_t *sample_buffer = ctx->sample_buffer;
    int32_t sample_mask[MAX_CHANNELS];
    unsigned int channel;
    int i;

    memset(sample_mask, 0x00, sizeof(sample_mask));

    for (i = 0; i < ctx->number_of_samples; i++) {
        for (channel = 0; channel <= rh->max_channel; channel++)
            sample_mask[channel] |= *sample_buffer++;

        sample_buffer += 2; /* noise channels */
    }

    for (channel = 0; channel <= rh->max_channel; channel++)
        dp->quant_step_size[channel] = number_trailing_zeroes(sample_mask[channel]) - mp->shift[channel];
}

/** Determines the smallest number of bits needed to encode the filter
 *  coefficients, and if it's possible to right-shift their values without
 *  losing any precision.
 */
static void code_filter_coeffs(MLPEncodeContext *ctx, FilterParams *fp, int32_t *fcoeff)
{
    int min = INT_MAX, max = INT_MIN;
    int bits, shift;
    int coeff_mask = 0;
    int order;

    for (order = 0; order < fp->order; order++) {
        int coeff = fcoeff[order];

        if (coeff < min)
            min = coeff;
        if (coeff > max)
            max = coeff;

        coeff_mask |= coeff;
    }

    bits = FFMAX(number_sbits(min), number_sbits(max));

    for (shift = 0; shift < 7 && bits + shift < 16 && !(coeff_mask & (1<<shift)); shift++);

    fp->coeff_bits  = bits;
    fp->coeff_shift = shift;
}

/** Determines the best filter parameters for the given data and writes the
 *  necessary information to the context.
 *  TODO Add IIR filter predictor!
 */
static void set_filter_params(MLPEncodeContext *ctx,
                              unsigned int channel, unsigned int filter,
                              int clear_filter)
{
    ChannelParams *cp = &ctx->cur_channel_params[channel];
    FilterParams *fp = &cp->filter_params[filter];

    if ((filter == IIR && ctx->substream_info & SUBSTREAM_INFO_HIGH_RATE) ||
        clear_filter) {
        fp->order = 0;
    } else if (filter == IIR) {
        fp->order = 0;
    } else if (filter == FIR) {
        const int max_order = (ctx->substream_info & SUBSTREAM_INFO_HIGH_RATE)
                              ? 4 : MLP_MAX_LPC_ORDER;
        int32_t *sample_buffer = ctx->sample_buffer + channel;
        int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER];
        int32_t *lpc_samples = ctx->lpc_sample_buffer;
        int32_t *fcoeff = ctx->cur_channel_params[channel].coeff[filter];
        int shift[MLP_MAX_LPC_ORDER];
        unsigned int i;
        int order;

        for (i = 0; i < ctx->number_of_samples; i++) {
            *lpc_samples++ = *sample_buffer;
            sample_buffer += ctx->num_channels;
        }

        order = ff_lpc_calc_coefs(&ctx->lpc_ctx, ctx->lpc_sample_buffer,
                                  ctx->number_of_samples, MLP_MIN_LPC_ORDER,
                                  max_order, 11, coefs, shift, FF_LPC_TYPE_LEVINSON, 0,
                                  ORDER_METHOD_EST, MLP_MIN_LPC_SHIFT,
                                  MLP_MAX_LPC_SHIFT, MLP_MIN_LPC_SHIFT);

        fp->order = order;
        fp->shift = shift[order-1];

        for (i = 0; i < order; i++)
            fcoeff[i] = coefs[order-1][i];

        code_filter_coeffs(ctx, fp, fcoeff);
    }
}

/** Tries to determine a good prediction filter, and applies it to the samples
 *  buffer if the filter is good enough. Sets the filter data to be cleared if
 *  no good filter was found.
 */
static void determine_filters(MLPEncodeContext *ctx)
{
    RestartHeader *rh = ctx->cur_restart_header;
    int channel, filter;

    for (channel = rh->min_channel; channel <= rh->max_channel; channel++) {
        for (filter = 0; filter < NUM_FILTERS; filter++)
            set_filter_params(ctx, channel, filter, 0);
    }
}

enum MLPChMode {
    MLP_CHMODE_LEFT_RIGHT,
    MLP_CHMODE_LEFT_SIDE,
    MLP_CHMODE_RIGHT_SIDE,
    MLP_CHMODE_MID_SIDE,
};

static enum MLPChMode estimate_stereo_mode(MLPEncodeContext *ctx)
{
    uint64_t score[4], sum[4] = { 0, 0, 0, 0, };
    int32_t *right_ch = ctx->sample_buffer + 1;
    int32_t *left_ch  = ctx->sample_buffer;
    int i;
    enum MLPChMode best = 0;

    for(i = 2; i < ctx->number_of_samples; i++) {
        int32_t left  = left_ch [i * ctx->num_channels] - 2 * left_ch [(i - 1) * ctx->num_channels] + left_ch [(i - 2) * ctx->num_channels];
        int32_t right = right_ch[i * ctx->num_channels] - 2 * right_ch[(i - 1) * ctx->num_channels] + right_ch[(i - 2) * ctx->num_channels];

        sum[0] += FFABS( left        );
        sum[1] += FFABS(        right);
        sum[2] += FFABS((left + right) >> 1);
        sum[3] += FFABS( left - right);
    }

    score[MLP_CHMODE_LEFT_RIGHT] = sum[0] + sum[1];
    score[MLP_CHMODE_LEFT_SIDE]  = sum[0] + sum[3];
    score[MLP_CHMODE_RIGHT_SIDE] = sum[1] + sum[3];
    score[MLP_CHMODE_MID_SIDE]   = sum[2] + sum[3];

    for(i = 1; i < 3; i++)
        if(score[i] < score[best])
            best = i;

    return best;
}

/** Determines how many fractional bits are needed to encode matrix
 *  coefficients. Also shifts the coefficients to fit within 2.14 bits.
 */
static void code_matrix_coeffs(MLPEncodeContext *ctx, unsigned int mat)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    MatrixParams *mp = &dp->matrix_params;
    int32_t coeff_mask = 0;
    unsigned int channel;
    unsigned int bits;

    for (channel = 0; channel < ctx->num_channels; channel++) {
        int32_t coeff = mp->coeff[mat][channel];
        coeff_mask |= coeff;
    }

    for (bits = 0; bits < 14 && !(coeff_mask & (1<<bits)); bits++);

    mp->fbits   [mat] = 14 - bits;
}

/** Determines best coefficients to use for the lossless matrix. */
static void lossless_matrix_coeffs(MLPEncodeContext *ctx)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    MatrixParams *mp = &dp->matrix_params;
    unsigned int shift = 0;
    unsigned int channel;
    int mat;
    enum MLPChMode mode;

    /* No decorrelation for non-stereo. */
    if (ctx->num_channels - 2 != 2) {
        mp->count = 0;
        return;
    }

    mode = estimate_stereo_mode(ctx);

    switch(mode) {
        /* TODO: add matrix for MID_SIDE */
        case MLP_CHMODE_MID_SIDE:
        case MLP_CHMODE_LEFT_RIGHT:
            mp->count    = 0;
            break;
        case MLP_CHMODE_LEFT_SIDE:
            mp->count    = 1;
            mp->outch[0] = 1;
            mp->coeff[0][0] =  1 << 14; mp->coeff[0][1] = -(1 << 14);
            mp->coeff[0][2] =  0 << 14; mp->coeff[0][2] =   0 << 14;
            mp->forco[0][0] =  1 << 14; mp->forco[0][1] = -(1 << 14);
            mp->forco[0][2] =  0 << 14; mp->forco[0][2] =   0 << 14;
            break;
        case MLP_CHMODE_RIGHT_SIDE:
            mp->count    = 1;
            mp->outch[0] = 0;
            mp->coeff[0][0] =  1 << 14; mp->coeff[0][1] =   1 << 14;
            mp->coeff[0][2] =  0 << 14; mp->coeff[0][2] =   0 << 14;
            mp->forco[0][0] =  1 << 14; mp->forco[0][1] = -(1 << 14);
            mp->forco[0][2] =  0 << 14; mp->forco[0][2] =   0 << 14;
            break;
    }

    for (mat = 0; mat < mp->count; mat++)
        code_matrix_coeffs(ctx, mat);

    for (channel = 0; channel < ctx->num_channels; channel++)
        mp->shift[channel] = shift;
}

/** Min and max values that can be encoded with each codebook. The values for
 *  the third codebook take into account the fact that the sign shift for this
 *  codebook is outside the coded value, so it has one more bit of precision.
 *  It should actually be -7 -> 7, shifted down by 0.5.
 */
static const int codebook_extremes[3][2] = {
    {-9, 8}, {-8, 7}, {-15, 14},
};

/** Determines the amount of bits needed to encode the samples using no
 *  codebooks and a specified offset.
 */
static void no_codebook_bits_offset(MLPEncodeContext *ctx,
                                    unsigned int channel, int16_t offset,
                                    int32_t min, int32_t max,
                                    BestOffset *bo)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    int32_t unsign = 0;
    int lsb_bits;

    min -= offset;
    max -= offset;

    lsb_bits = FFMAX(number_sbits(min), number_sbits(max)) - 1;

    lsb_bits += !!lsb_bits;

    if (lsb_bits > 0)
        unsign = 1 << (lsb_bits - 1);

    bo->offset   = offset;
    bo->lsb_bits = lsb_bits;
    bo->bitcount = lsb_bits * dp->blocksize;
    bo->min      = offset - unsign + 1;
    bo->max      = offset + unsign;
}

/** Determines the least amount of bits needed to encode the samples using no
 *  codebooks.
 */
static void no_codebook_bits(MLPEncodeContext *ctx,
                             unsigned int channel,
                             int32_t min, int32_t max,
                             BestOffset *bo)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    int16_t offset;
    int32_t unsign = 0;
    uint32_t diff;
    int lsb_bits;

    /* Set offset inside huffoffset's boundaries by adjusting extremes
     * so that more bits are used, thus shifting the offset. */
    if (min < HUFF_OFFSET_MIN)
        max = FFMAX(max, 2 * HUFF_OFFSET_MIN - min + 1);
    if (max > HUFF_OFFSET_MAX)
        min = FFMIN(min, 2 * HUFF_OFFSET_MAX - max - 1);

    /* Determine offset and minimum number of bits. */
    diff = max - min;

    lsb_bits = number_sbits(diff) - 1;

    if (lsb_bits > 0)
        unsign = 1 << (lsb_bits - 1);

    /* If all samples are the same (lsb_bits == 0), offset must be
     * adjusted because of sign_shift. */
    offset = min + diff / 2 + !!lsb_bits;

    bo->offset   = offset;
    bo->lsb_bits = lsb_bits;
    bo->bitcount = lsb_bits * dp->blocksize;
    bo->min      = max - unsign + 1;
    bo->max      = min + unsign;
}

/** Determines the least amount of bits needed to encode the samples using a
 *  given codebook and a given offset.
 */
static inline void codebook_bits_offset(MLPEncodeContext *ctx,
                                        unsigned int channel, int codebook,
                                        int32_t sample_min, int32_t sample_max,
                                        int16_t offset, BestOffset *bo)
{
    int32_t codebook_min = codebook_extremes[codebook][0];
    int32_t codebook_max = codebook_extremes[codebook][1];
    int32_t *sample_buffer = ctx->sample_buffer + channel;
    DecodingParams *dp = ctx->cur_decoding_params;
    int codebook_offset  = 7 + (2 - codebook);
    int32_t unsign_offset = offset;
    int lsb_bits = 0, bitcount = 0;
    int offset_min = INT_MAX, offset_max = INT_MAX;
    int unsign, mask;
    int i;

    sample_min -= offset;
    sample_max -= offset;

    while (sample_min < codebook_min || sample_max > codebook_max) {
        lsb_bits++;
        sample_min >>= 1;
        sample_max >>= 1;
    }

    unsign = 1 << lsb_bits;
    mask   = unsign - 1;

    if (codebook == 2) {
        unsign_offset -= unsign;
        lsb_bits++;
    }

    for (i = 0; i < dp->blocksize; i++) {
        int32_t sample = *sample_buffer >> dp->quant_step_size[channel];
        int temp_min, temp_max;

        sample -= unsign_offset;

        temp_min = sample & mask;
        if (temp_min < offset_min)
            offset_min = temp_min;

        temp_max = unsign - temp_min - 1;
        if (temp_max < offset_max)
            offset_max = temp_max;

        sample >>= lsb_bits;

        bitcount += ff_mlp_huffman_tables[codebook][sample + codebook_offset][1];

        sample_buffer += ctx->num_channels;
    }

    bo->offset   = offset;
    bo->lsb_bits = lsb_bits;
    bo->bitcount = lsb_bits * dp->blocksize + bitcount;
    bo->min      = FFMAX(offset - offset_min, HUFF_OFFSET_MIN);
    bo->max      = FFMIN(offset + offset_max, HUFF_OFFSET_MAX);
}

/** Determines the least amount of bits needed to encode the samples using a
 *  given codebook. Searches for the best offset to minimize the bits.
 */
static inline void codebook_bits(MLPEncodeContext *ctx,
                                 unsigned int channel, int codebook,
                                 int offset, int32_t min, int32_t max,
                                 BestOffset *bo, int direction)
{
    int previous_count = INT_MAX;
    int offset_min, offset_max;
    int is_greater = 0;

    offset_min = FFMAX(min, HUFF_OFFSET_MIN);
    offset_max = FFMIN(max, HUFF_OFFSET_MAX);

    while (offset <= offset_max && offset >= offset_min) {
        BestOffset temp_bo;

        codebook_bits_offset(ctx, channel, codebook,
                             min, max, offset,
                             &temp_bo);

        if (temp_bo.bitcount < previous_count) {
            if (temp_bo.bitcount < bo->bitcount)
                *bo = temp_bo;

            is_greater = 0;
        } else if (++is_greater >= ctx->max_codebook_search)
            break;

        previous_count = temp_bo.bitcount;

        if (direction) {
            offset = temp_bo.max + 1;
        } else {
            offset = temp_bo.min - 1;
        }
    }
}

/** Determines the least amount of bits needed to encode the samples using
 *  any or no codebook.
 */
static void determine_bits(MLPEncodeContext *ctx)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    RestartHeader  *rh = ctx->cur_restart_header;
    unsigned int channel;

    for (channel = 0; channel <= rh->max_channel; channel++) {
        ChannelParams *cp = &ctx->cur_channel_params[channel];
        int32_t *sample_buffer = ctx->sample_buffer + channel;
        int32_t min = INT32_MAX, max = INT32_MIN;
        int no_filters_used = !cp->filter_params[FIR].order;
        int average = 0;
        int offset = 0;
        int i;

        /* Determine extremes and average. */
        for (i = 0; i < dp->blocksize; i++) {
            int32_t sample = *sample_buffer >> dp->quant_step_size[channel];
            if (sample < min)
                min = sample;
            if (sample > max)
                max = sample;
            average += sample;
            sample_buffer += ctx->num_channels;
        }
        average /= dp->blocksize;

        /* If filtering is used, we always set the offset to zero, otherwise
         * we search for the offset that minimizes the bitcount. */
        if (no_filters_used) {
            no_codebook_bits(ctx, channel, min, max, &ctx->cur_best_offset[channel][0]);
            offset = av_clip(average, HUFF_OFFSET_MIN, HUFF_OFFSET_MAX);
        } else {
            no_codebook_bits_offset(ctx, channel, offset, min, max, &ctx->cur_best_offset[channel][0]);
        }

        for (i = 1; i < NUM_CODEBOOKS; i++) {
            BestOffset temp_bo = { 0, INT_MAX, 0, 0, 0, };
            int16_t offset_max;

            codebook_bits_offset(ctx, channel, i - 1,
                                 min, max, offset,
                                 &temp_bo);

            if (no_filters_used) {
                offset_max = temp_bo.max;

                codebook_bits(ctx, channel, i - 1, temp_bo.min - 1,
                            min, max, &temp_bo, 0);
                codebook_bits(ctx, channel, i - 1, offset_max + 1,
                            min, max, &temp_bo, 1);
            }

            ctx->cur_best_offset[channel][i] = temp_bo;
        }
    }
}

/****************************************************************************
 *************** Functions that process the data in some way ****************
 ****************************************************************************/

#define SAMPLE_MAX(bitdepth) ((1 << (bitdepth - 1)) - 1)
#define SAMPLE_MIN(bitdepth) (~SAMPLE_MAX(bitdepth))

#define MSB_MASK(bits)  (-(int)(1u << (bits)))

/** Applies the filter to the current samples, and saves the residual back
 *  into the samples buffer. If the filter is too bad and overflows the
 *  maximum amount of bits allowed (24), the samples buffer is left as is and
 *  the function returns -1.
 */
static int apply_filter(MLPEncodeContext *ctx, unsigned int channel)
{
    FilterParams *fp[NUM_FILTERS] = { &ctx->cur_channel_params[channel].filter_params[FIR],
                                      &ctx->cur_channel_params[channel].filter_params[IIR], };
    int32_t *filter_state_buffer[NUM_FILTERS] = { NULL };
    int32_t mask = MSB_MASK(ctx->cur_decoding_params->quant_step_size[channel]);
    int32_t *sample_buffer = ctx->sample_buffer + channel;
    unsigned int number_of_samples = ctx->number_of_samples;
    unsigned int filter_shift = fp[FIR]->shift;
    int filter;
    int i, ret = 0;

    for (i = 0; i < NUM_FILTERS; i++) {
        unsigned int size = ctx->number_of_samples;
        filter_state_buffer[i] = av_malloc(size*sizeof(int32_t));
        if (!filter_state_buffer[i]) {
            av_log(ctx->avctx, AV_LOG_ERROR,
                   "Not enough memory for applying filters.\n");
            ret = AVERROR(ENOMEM);
            goto free_and_return;
        }
    }

    for (i = 0; i < 8; i++) {
        filter_state_buffer[FIR][i] = *sample_buffer;
        filter_state_buffer[IIR][i] = *sample_buffer;

        sample_buffer += ctx->num_channels;
    }

    for (i = 8; i < number_of_samples; i++) {
        int32_t sample = *sample_buffer;
        unsigned int order;
        int64_t accum = 0;
        int64_t residual;

        for (filter = 0; filter < NUM_FILTERS; filter++) {
            int32_t *fcoeff = ctx->cur_channel_params[channel].coeff[filter];
            for (order = 0; order < fp[filter]->order; order++)
                accum += (int64_t)filter_state_buffer[filter][i - 1 - order] *
                         fcoeff[order];
        }

        accum  >>= filter_shift;
        residual = sample - (accum & mask);

        if (residual < SAMPLE_MIN(24) || residual > SAMPLE_MAX(24)) {
            ret = AVERROR_INVALIDDATA;
            goto free_and_return;
        }

        filter_state_buffer[FIR][i] = sample;
        filter_state_buffer[IIR][i] = (int32_t) residual;

        sample_buffer += ctx->num_channels;
    }

    sample_buffer = ctx->sample_buffer + channel;
    for (i = 0; i < number_of_samples; i++) {
        *sample_buffer = filter_state_buffer[IIR][i];

        sample_buffer += ctx->num_channels;
    }

free_and_return:
    for (i = 0; i < NUM_FILTERS; i++) {
        av_freep(&filter_state_buffer[i]);
    }

    return ret;
}

static void apply_filters(MLPEncodeContext *ctx)
{
    RestartHeader *rh = ctx->cur_restart_header;
    int channel;

    for (channel = rh->min_channel; channel <= rh->max_channel; channel++) {
        if (apply_filter(ctx, channel) < 0) {
            /* Filter is horribly wrong.
             * Clear filter params and update state. */
            set_filter_params(ctx, channel, FIR, 1);
            set_filter_params(ctx, channel, IIR, 1);
            apply_filter(ctx, channel);
        }
    }
}

/** Generates two noise channels worth of data. */
static void generate_2_noise_channels(MLPEncodeContext *ctx)
{
    int32_t *sample_buffer = ctx->sample_buffer + ctx->num_channels - 2;
    RestartHeader *rh = ctx->cur_restart_header;
    unsigned int i;
    uint32_t seed = rh->noisegen_seed;

    for (i = 0; i < ctx->number_of_samples; i++) {
        uint16_t seed_shr7 = seed >> 7;
        *sample_buffer++ = ((int8_t)(seed >> 15)) * (1 << rh->noise_shift);
        *sample_buffer++ = ((int8_t) seed_shr7)   * (1 << rh->noise_shift);

        seed = (seed << 16) ^ seed_shr7 ^ (seed_shr7 << 5);

        sample_buffer += ctx->num_channels - 2;
    }

    rh->noisegen_seed = seed & ((1 << 24)-1);
}

/** Rematrixes all channels using chosen coefficients. */
static void rematrix_channels(MLPEncodeContext *ctx)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    MatrixParams *mp = &dp->matrix_params;
    int32_t *sample_buffer = ctx->sample_buffer;
    unsigned int mat, i, maxchan;

    maxchan = ctx->num_channels;

    for (mat = 0; mat < mp->count; mat++) {
        unsigned int msb_mask_bits = (ctx->avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 8 : 0) - mp->shift[mat];
        int32_t mask = MSB_MASK(msb_mask_bits);
        unsigned int outch = mp->outch[mat];

        sample_buffer = ctx->sample_buffer;
        for (i = 0; i < ctx->number_of_samples; i++) {
            unsigned int src_ch;
            int64_t accum = 0;

            for (src_ch = 0; src_ch < maxchan; src_ch++) {
                int32_t sample = *(sample_buffer + src_ch);
                accum += (int64_t) sample * mp->forco[mat][src_ch];
            }
            sample_buffer[outch] = (accum >> 14) & mask;

            sample_buffer += ctx->num_channels;
        }
    }
}

/****************************************************************************
 **** Functions that deal with determining the best parameters and output ***
 ****************************************************************************/

typedef struct {
    char    path[MAJOR_HEADER_INTERVAL + 2];
    int     cur_idx;
    int     bitcount;
} PathCounter;

#define CODEBOOK_CHANGE_BITS    21

static void clear_path_counter(PathCounter *path_counter)
{
    memset(path_counter, 0, (NUM_CODEBOOKS + 1) * sizeof(*path_counter));
}

static int compare_best_offset(const BestOffset *prev, const BestOffset *cur)
{
    if (prev->lsb_bits != cur->lsb_bits)
        return 1;

    return 0;
}

static int best_codebook_path_cost(MLPEncodeContext *ctx, unsigned int channel,
                                   PathCounter *src, int cur_codebook)
{
    int idx = src->cur_idx;
    const BestOffset *cur_bo = ctx->best_offset[idx][channel],
                    *prev_bo = idx ? ctx->best_offset[idx - 1][channel] :
                                     restart_best_offset;
    int bitcount = src->bitcount;
    int prev_codebook = src->path[idx];

    bitcount += cur_bo[cur_codebook].bitcount;

    if (prev_codebook != cur_codebook ||
        compare_best_offset(&prev_bo[prev_codebook], &cur_bo[cur_codebook]))
        bitcount += CODEBOOK_CHANGE_BITS;

    return bitcount;
}

static void set_best_codebook(MLPEncodeContext *ctx)
{
    DecodingParams *dp = ctx->cur_decoding_params;
    RestartHeader *rh = ctx->cur_restart_header;
    unsigned int channel;

    for (channel = rh->min_channel; channel <= rh->max_channel; channel++) {
        const BestOffset *prev_bo = restart_best_offset;
        BestOffset *cur_bo;
        PathCounter path_counter[NUM_CODEBOOKS + 1];
        unsigned int best_codebook;
        unsigned int index;
        char *best_path;

        clear_path_counter(path_counter);

        for (index = 0; index < ctx->number_of_subblocks; index++) {
            unsigned int best_bitcount = INT_MAX;
            unsigned int codebook;

            cur_bo = ctx->best_offset[index][channel];

            for (codebook = 0; codebook < NUM_CODEBOOKS; codebook++) {
                int prev_best_bitcount = INT_MAX;
                int last_best;

                for (last_best = 0; last_best < 2; last_best++) {
                    PathCounter *dst_path = &path_counter[codebook];
                    PathCounter *src_path;
                    int  temp_bitcount;

                    /* First test last path with same headers,
                     * then with last best. */
                    if (last_best) {
                        src_path = &path_counter[NUM_CODEBOOKS];
                    } else {
                        if (compare_best_offset(&prev_bo[codebook], &cur_bo[codebook]))
                            continue;
                        else
                            src_path = &path_counter[codebook];
                    }

                    temp_bitcount = best_codebook_path_cost(ctx, channel, src_path, codebook);

                    if (temp_bitcount < best_bitcount) {
                        best_bitcount = temp_bitcount;
                        best_codebook = codebook;
                    }

                    if (temp_bitcount < prev_best_bitcount) {
                        prev_best_bitcount = temp_bitcount;
                        if (src_path != dst_path)
                            memcpy(dst_path, src_path, sizeof(PathCounter));
                        if (dst_path->cur_idx < FF_ARRAY_ELEMS(dst_path->path) - 1)
                            dst_path->path[++dst_path->cur_idx] = codebook;
                        dst_path->bitcount = temp_bitcount;
                    }
                }
            }

            prev_bo = cur_bo;

            memcpy(&path_counter[NUM_CODEBOOKS], &path_counter[best_codebook], sizeof(PathCounter));
        }

        best_path = path_counter[NUM_CODEBOOKS].path + 1;

        /* Update context. */
        for (index = 0; index < ctx->number_of_subblocks; index++) {
            ChannelParams *cp = ctx->seq_channel_params + index*(ctx->avctx->channels) + channel;

            best_codebook = *best_path++;
            cur_bo = &ctx->best_offset[index][channel][best_codebook];

            cp->huff_offset      = cur_bo->offset;
            cp->huff_lsbs        = cur_bo->lsb_bits + dp->quant_step_size[channel];
            cp->codebook         = best_codebook;
        }
    }
}

/** Analyzes all collected bitcounts and selects the best parameters for each
 *  individual access unit.
 *  TODO This is just a stub!
 */
static void set_major_params(MLPEncodeContext *ctx)
{
    RestartHeader *rh = ctx->cur_restart_header;
    unsigned int index;
    unsigned int substr;
    uint8_t max_huff_lsbs = 0;
    uint8_t max_output_bits = 0;

    for (substr = 0; substr < ctx->num_substreams; substr++) {
        DecodingParams *seq_dp = (DecodingParams *) ctx->decoding_params+
                                 (ctx->restart_intervals - 1)*(ctx->sequence_size)*(ctx->avctx->channels) +
                                 (ctx->seq_offset[ctx->restart_intervals - 1])*(ctx->avctx->channels);

        ChannelParams *seq_cp = (ChannelParams *) ctx->channel_params +
                                (ctx->restart_intervals - 1)*(ctx->sequence_size)*(ctx->avctx->channels) +
                                (ctx->seq_offset[ctx->restart_intervals - 1])*(ctx->avctx->channels);
        unsigned int channel;
        for (index = 0; index < ctx->seq_size[ctx->restart_intervals-1]; index++) {
            memcpy(&ctx->major_decoding_params[index][substr], seq_dp + index*(ctx->num_substreams) + substr, sizeof(DecodingParams));
            for (channel = 0; channel < ctx->avctx->channels; channel++) {
                uint8_t huff_lsbs = (seq_cp + index*(ctx->avctx->channels) + channel)->huff_lsbs;
                if (max_huff_lsbs < huff_lsbs)
                    max_huff_lsbs = huff_lsbs;
                memcpy(&ctx->major_channel_params[index][channel],
                       (seq_cp + index*(ctx->avctx->channels) + channel),
                       sizeof(ChannelParams));
            }
        }
    }

    rh->max_huff_lsbs = max_huff_lsbs;

    for (index = 0; index < ctx->number_of_frames; index++)
        if (max_output_bits < ctx->max_output_bits[index])
            max_output_bits = ctx->max_output_bits[index];
    rh->max_output_bits = max_output_bits;

    for (substr = 0; substr < ctx->num_substreams; substr++) {

        ctx->cur_restart_header = &ctx->restart_header[substr];

        ctx->prev_decoding_params = &restart_decoding_params[substr];
        ctx->prev_channel_params = restart_channel_params;

        for (index = 0; index < MAJOR_HEADER_INTERVAL + 1; index++) {
                ctx->cur_decoding_params = &ctx->major_decoding_params[index][substr];
                ctx->cur_channel_params = ctx->major_channel_params[index];

                ctx->major_params_changed[index][substr] = compare_decoding_params(ctx);

                ctx->prev_decoding_params = ctx->cur_decoding_params;
                ctx->prev_channel_params = ctx->cur_channel_params;
        }
    }

    ctx->major_number_of_subblocks = ctx->number_of_subblocks;
    ctx->major_filter_state_subblock = 1;
    ctx->major_cur_subblock_index = 0;
}

static void analyze_sample_buffer(MLPEncodeContext *ctx)
{
    ChannelParams *seq_cp = ctx->seq_channel_params;
    DecodingParams *seq_dp = ctx->seq_decoding_params;
    unsigned int index;
    unsigned int substr;

    for (substr = 0; substr < ctx->num_substreams; substr++) {

        ctx->cur_restart_header = &ctx->restart_header[substr];
        ctx->cur_decoding_params = seq_dp + 1*(ctx->num_substreams) + substr;
        ctx->cur_channel_params = seq_cp + 1*(ctx->avctx->channels);

        determine_quant_step_size(ctx);
        generate_2_noise_channels(ctx);
        lossless_matrix_coeffs   (ctx);
        rematrix_channels        (ctx);
        determine_filters        (ctx);
        apply_filters            (ctx);

        copy_restart_frame_params(ctx, substr);

        /* Copy frame_size from frames 0...max to decoding_params 1...max + 1
         * decoding_params[0] is for the filter state subblock.
         */
        for (index = 0; index < ctx->number_of_frames; index++) {
            DecodingParams *dp = seq_dp + (index + 1)*(ctx->num_substreams) + substr;
            dp->blocksize = ctx->frame_size[index];
        }
        /* The official encoder seems to always encode a filter state subblock
         * even if there are no filters. TODO check if it is possible to skip
         * the filter state subblock for no filters.
         */
        (seq_dp + substr)->blocksize  = 8;
        (seq_dp + 1*(ctx->num_substreams) + substr)->blocksize -= 8;

        for (index = 0; index < ctx->number_of_subblocks; index++) {
                ctx->cur_decoding_params = seq_dp + index*(ctx->num_substreams) + substr;
                ctx->cur_channel_params = seq_cp + index*(ctx->avctx->channels);
                ctx->cur_best_offset = ctx->best_offset[index];
                determine_bits(ctx);
                ctx->sample_buffer += ctx->cur_decoding_params->blocksize * ctx->num_channels;
        }

        set_best_codebook(ctx);
    }
}

static void process_major_frame(MLPEncodeContext *ctx)
{
    unsigned int substr;

    ctx->sample_buffer = ctx->major_inout_buffer;

    ctx->starting_frame_index = 0;
    ctx->number_of_frames = ctx->major_number_of_frames;
    ctx->number_of_samples = ctx->major_frame_size;

    for (substr = 0; substr < ctx->num_substreams; substr++) {
        ctx->cur_restart_header = &ctx->restart_header[substr];

        ctx->cur_decoding_params = &ctx->major_decoding_params[1][substr];
        ctx->cur_channel_params = ctx->major_channel_params[1];

        generate_2_noise_channels(ctx);
        rematrix_channels        (ctx);

        apply_filters(ctx);
    }
}

/****************************************************************************/

static int mlp_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
                            const AVFrame *frame, int *got_packet)
{
    MLPEncodeContext *ctx = avctx->priv_data;
    unsigned int bytes_written = 0;
    int restart_frame, ret;
    uint8_t *data;

    if ((ret = ff_alloc_packet(avctx, avpkt, 87500 * avctx->channels)) < 0)
        return ret;

    /* add current frame to queue */
    if ((ret = ff_af_queue_add(&ctx->afq, frame)) < 0)
        return ret;

    data = frame->data[0];

    ctx->frame_index = avctx->frame_number % ctx->max_restart_interval;

    ctx->inout_buffer = ctx->major_inout_buffer
                      + ctx->frame_index * ctx->one_sample_buffer_size;

    if (ctx->last_frame == ctx->inout_buffer) {
        return 0;
    }

    ctx->sample_buffer = ctx->major_scratch_buffer
                       + ctx->frame_index * ctx->one_sample_buffer_size;

    ctx->write_buffer = ctx->inout_buffer;

    if (avctx->frame_number < ctx->max_restart_interval) {
        if (data) {
            goto input_and_return;
        } else {
            /* There are less frames than the requested major header interval.
             * Update the context to reflect this.
             */
            ctx->max_restart_interval = avctx->frame_number;
            ctx->frame_index = 0;

            ctx->sample_buffer = ctx->major_scratch_buffer;
            ctx->inout_buffer = ctx->major_inout_buffer;
        }
    }

    if (ctx->frame_size[ctx->frame_index] > MAX_BLOCKSIZE) {
        av_log(avctx, AV_LOG_ERROR, "Invalid frame size (%d > %d)\n",
               ctx->frame_size[ctx->frame_index], MAX_BLOCKSIZE);
        return AVERROR_INVALIDDATA;
    }

    restart_frame = !ctx->frame_index;

    if (restart_frame) {
        set_major_params(ctx);
        if (ctx->min_restart_interval != ctx->max_restart_interval)
            process_major_frame(ctx);
    }

    if (ctx->min_restart_interval == ctx->max_restart_interval)
        ctx->write_buffer = ctx->sample_buffer;

    bytes_written = write_access_unit(ctx, avpkt->data, avpkt->size, restart_frame);

    ctx->timestamp += ctx->frame_size[ctx->frame_index];
    ctx->dts       += ctx->frame_size[ctx->frame_index];

input_and_return:

    if (data) {
        ctx->frame_size[ctx->frame_index] = avctx->frame_size;
        ctx->next_major_frame_size += avctx->frame_size;
        ctx->next_major_number_of_frames++;
        input_data(ctx, data);
    } else if (!ctx->last_frame) {
        ctx->last_frame = ctx->inout_buffer;
    }

    restart_frame = (ctx->frame_index + 1) % ctx->min_restart_interval;

    if (!restart_frame) {
        int seq_index;

        for (seq_index = 0;
             seq_index < ctx->restart_intervals && (seq_index * ctx->min_restart_interval) <= ctx->avctx->frame_number;
             seq_index++) {
            unsigned int number_of_samples = 0;
            unsigned int index;

            ctx->sample_buffer = ctx->major_scratch_buffer;
            ctx->inout_buffer = ctx->major_inout_buffer;
            ctx->seq_index = seq_index;

            ctx->starting_frame_index = (ctx->avctx->frame_number - (ctx->avctx->frame_number % ctx->min_restart_interval)
                                      - (seq_index * ctx->min_restart_interval)) % ctx->max_restart_interval;
            ctx->number_of_frames = ctx->next_major_number_of_frames;
            ctx->number_of_subblocks = ctx->next_major_number_of_frames + 1;

            ctx->seq_channel_params = (ChannelParams *) ctx->channel_params +
                                      (ctx->frame_index / ctx->min_restart_interval)*(ctx->sequence_size)*(ctx->avctx->channels) +
                                      (ctx->seq_offset[seq_index])*(ctx->avctx->channels);

            ctx->seq_decoding_params = (DecodingParams *) ctx->decoding_params +
                                       (ctx->frame_index / ctx->min_restart_interval)*(ctx->sequence_size)*(ctx->num_substreams) +
                                       (ctx->seq_offset[seq_index])*(ctx->num_substreams);

            for (index = 0; index < ctx->number_of_frames; index++) {
                number_of_samples += ctx->frame_size[(ctx->starting_frame_index + index) % ctx->max_restart_interval];
            }
            ctx->number_of_samples = number_of_samples;

            for (index = 0; index < ctx->seq_size[seq_index]; index++) {
                clear_channel_params(ctx->seq_channel_params + index * ctx->avctx->channels, ctx->avctx->channels);
                default_decoding_params(ctx, ctx->seq_decoding_params + index*(ctx->num_substreams));
            }

            input_to_sample_buffer(ctx);

            analyze_sample_buffer(ctx);
        }

        if (ctx->frame_index == (ctx->max_restart_interval - 1)) {
            ctx->major_frame_size = ctx->next_major_frame_size;
            ctx->next_major_frame_size = 0;
            ctx->major_number_of_frames = ctx->next_major_number_of_frames;
            ctx->next_major_number_of_frames = 0;

            if (!ctx->major_frame_size)
                goto no_data_left;
        }
    }

no_data_left:

    ff_af_queue_remove(&ctx->afq, avctx->frame_size, &avpkt->pts,
                       &avpkt->duration);
    avpkt->size = bytes_written;
    *got_packet = 1;
    return 0;
}

static av_cold int mlp_encode_close(AVCodecContext *avctx)
{
    MLPEncodeContext *ctx = avctx->priv_data;

    ff_lpc_end(&ctx->lpc_ctx);

    av_freep(&ctx->lossless_check_data);
    av_freep(&ctx->major_scratch_buffer);
    av_freep(&ctx->major_inout_buffer);
    av_freep(&ctx->lpc_sample_buffer);
    av_freep(&ctx->decoding_params);
    av_freep(&ctx->channel_params);
    av_freep(&ctx->frame_size);
    av_freep(&ctx->max_output_bits);
    ff_af_queue_close(&ctx->afq);

    return 0;
}

#if CONFIG_MLP_ENCODER
const AVCodec ff_mlp_encoder = {
    .name                   ="mlp",
    .long_name              = NULL_IF_CONFIG_SMALL("MLP (Meridian Lossless Packing)"),
    .type                   = AVMEDIA_TYPE_AUDIO,
    .id                     = AV_CODEC_ID_MLP,
    .priv_data_size         = sizeof(MLPEncodeContext),
    .init                   = mlp_encode_init,
    .encode2                = mlp_encode_frame,
    .close                  = mlp_encode_close,
    .capabilities           = AV_CODEC_CAP_SMALL_LAST_FRAME | AV_CODEC_CAP_EXPERIMENTAL,
    .sample_fmts            = (const enum AVSampleFormat[]) {AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE},
    .supported_samplerates  = (const int[]) {44100, 48000, 88200, 96000, 176400, 192000, 0},
    .channel_layouts        = ff_mlp_channel_layouts,
    .caps_internal          = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
};
#endif
#if CONFIG_TRUEHD_ENCODER
const AVCodec ff_truehd_encoder = {
    .name                   ="truehd",
    .long_name              = NULL_IF_CONFIG_SMALL("TrueHD"),
    .type                   = AVMEDIA_TYPE_AUDIO,
    .id                     = AV_CODEC_ID_TRUEHD,
    .priv_data_size         = sizeof(MLPEncodeContext),
    .init                   = mlp_encode_init,
    .encode2                = mlp_encode_frame,
    .close                  = mlp_encode_close,
    .capabilities           = AV_CODEC_CAP_SMALL_LAST_FRAME | AV_CODEC_CAP_EXPERIMENTAL,
    .sample_fmts            = (const enum AVSampleFormat[]) {AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE},
    .supported_samplerates  = (const int[]) {44100, 48000, 88200, 96000, 176400, 192000, 0},
    .channel_layouts        = (const uint64_t[]) {AV_CH_LAYOUT_STEREO, AV_CH_LAYOUT_5POINT0_BACK, AV_CH_LAYOUT_5POINT1_BACK, 0},
    .caps_internal          = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
};
#endif