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
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- Copyright (c) 2000,2001 Josh Coalson -->
<!-- Permission is granted to copy, distribute and/or modify this document -->
<!-- under the terms of the GNU Free Documentation License, Version 1.1 -->
<!-- or any later version published by the Free Software Foundation; -->
<!-- with no invariant sections. -->
<!-- A copy of the license can be found at http://www.gnu.org/copyleft/fdl.html -->
<HTML>
<HEAD>
<TITLE>FLAC - documentation</TITLE>
</HEAD>
<BODY MARGINWIDTH="0" MARGINHEIGHT="0" LEFTMARGIN="0" RIGHTMARGIN="0" TOPMARGIN="0" BGCOLOR="#99CC99" TEXT="#000000" LINK="#336699" VLINK="#336699" ALINK="#336699">
<TABLE BORDER=0 WIDTH="100%" CELLPADDING=1 CELLSPACING=0>
<TR>
<TD ALIGN="CENTER" BGCOLOR="#000000"><A HREF="http://flac.sourceforge.net/"><IMG SRC="images/logo.jpg" ALIGN=CENTER ALT="FLAC Logo" BORDER=0 HSPACE=0></a></TD>
</TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#99CC99"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="25" ALT=""></TD></TR></TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="2" ALT=""></TD></TR></TABLE>
<TABLE WIDTH="100%" CELLPADDING=0 CELLSPACING=0 BORDER=0>
<TR>
<TD ALIGN="CENTER" BGCOLOR="#D3D4C5">
<TABLE CELLPADDING=0 CELLSPACING=0 BORDER=0>
<TR>
<TD HEIGHT=22 BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="index.html">home</A> </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="news.html">news</A> </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="download.html">download</A> </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="features.html">features</A> </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="goals.html">goals</A> </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="format.html">format</A> </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="id.html">id</A> </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="comparison.html">comparison</A> </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> documentation </TD><TD BGCOLOR="#D3D4C5" ALIGN=CENTER>|</TD>
<TD BGCOLOR="#D3D4C5" ALIGN=CENTER NOWRAP> <A CLASS="topnav" HREF="developers.html">developers</A> </TD>
</TR>
</TABLE>
</TD>
</TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="2" ALT=""></TD></TR></TABLE>
<CENTER>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#99CC99"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="15" ALT=""></TD></TR></TABLE>
<TABLE WIDTH="100%" CELLPADDING="5" CELLSPACING="5" BORDER="0">
<TR><TD>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#D3D4C5">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<B><FONT SIZE="+2">documentation</FONT></B>
</FONT></TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#EEEED4">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<P>
This page describes the user-level view of the FLAC format (for a more detailed explanation see the <A HREF="format.html">format page</A>). It also contains the user documentation for <B><TT>flac</TT></B>, which is the command-line file encoder/decoder, <B><TT>metaflac</TT></B>, the FLAC metadata editor, and the <A HREF="#plugins">input plugins</A>.
</P>
<P>
Keep in mind that the online version of this document will always apply to the latest release. For older releases, check the documentation included with the release package.
</P>
</FONT>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="5" CELLSPACING="5" BORDER="0">
<TR><TD>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#D3D4C5">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<B><FONT SIZE="+2">format</FONT></B>
</FONT></TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#EEEED4">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<P>
<B><TT>flac</TT></B> has been tuned so that the default options yield a good speed vs. compression tradeoff for many kinds of input. However, if you are looking to maximize the compression rate or speed, or want to use the full power of FLAC's metadata system, this section is for you. If not, just skip to the <A HREF="#flac">next section</A>.
</P>
<P>
The basic structure of a FLAC stream is:
<UL>
<LI>The four byte string "fLaC"</LI>
<LI>The <A HREF="format.html#def_STREAMINFO">STREAMINFO</A> metadata block</LI>
<LI>Zero or more other metadata blocks</LI>
<LI>One or more audio frames</LI>
</UL>
</P>
<P>
The first four bytes are to identify the FLAC stream. The metadata that follows contains all the information about the stream except for the audio data itself. After the metadata comes the encoded audio data.
</P>
<P>
<B>METADATA</B>
</P>
<P>
FLAC defines several types of metadata blocks (see the <A HREF="format.html">format</A> page for the complete list. Metadata blocks can be any length and new ones can be defined. A decoder is allowed to skip any metadata types it does not understand. Only one is mandatory: the STREAMINFO block. This block has information like the sample rate, number of channels, etc., and data that can help the decoder manage its buffers, like the minimum and maximum data rate and minimum and maximum block size. Also included in the STREAMINFO block is the MD5 signature of the <I>unencoded</I> audio data. This is useful for checking an entire stream for transmission errors.
</P>
<P>
Other blocks allow for padding, seek tables, and application-specific data. You can see <B><TT>flac</TT></B> options below for adding PADDING blocks or specifying seek points. FLAC does not require seek points for seeking but they can speed up seeks, or be used for cueing in editing applications.
<P>
</P>
Also, if you have a need of a custom metadata block, you can define your own and request an ID <A HREF="id.html">here</A>. Then you can reserve a PADDING block of the correct size when encoding, and overwrite the padding block with your APPLICATION block after encoding. The resulting stream will be FLAC compatible; decoders that are aware of your metadata can use it and the rest will safely ignore it.
</P>
<P>
<B>AUDIO DATA</B>
</P>
<P>
After the metadata comes the encoded audio data. Audio data and metadata are not interleaved. Like most audio codecs, FLAC splits the unencoded audio data into blocks, and encodes each block separately. The encoded block is packed into a frame and appended to the stream. The reference encoder uses a single block size for the whole stream but the FLAC format does not require it.
</P>
<P>
<B>BLOCKING</B>
</P>
<P>
The block size is an important parameter to encoding. If it is too small, the frame overhead will lower the compression. If it is too large, the modeling stage of the compressor will not be able to generate an efficient model. Understanding FLAC's modeling will help you to improve compression for some kinds of input by varying the block size. In the most general case, using linear prediction on 44.1kHz audio, the optimal block size will be between 2-6 ksamples. <B><TT>flac</TT></B> defaults to a block size of 4608 in this case. Using the fast fixed predictors, a smaller block size is usually preferable because of the smaller frame header.
</P>
<P>
<B>INTER-CHANNEL DECORRELATION</B>
</P>
<P>
In the case of stereo input, once the data is blocked it is optionally passed through an inter-channel decorrelation stage. The left and right channels are converted to center and side channels through the following transformation: mid = (left + right) / 2, side = left - right. This is a lossless process, unlike joint stereo. For normal CD audio this can result in significant extra compression. <B><TT>flac</TT></B> has two options for this: <TT>-m</TT> always compresses both the left-right and mid-side versions of the block and takes the smallest frame, and <TT>-M</TT>, which adaptively switches between left-right and mid-side.
</P>
<P>
<B>MODELING</B>
</P>
<P>
In the next stage, the encoder tries to approximate the signal with a function in such a way that when the approximation is subracted, the result (called the <I>residual</I>, <I>residue</I>, or <I>error</I>) requires fewer bits-per-sample to encode. The function's parameters also have to be transmitted so they should not be so complex as to eat up the savings. FLAC has two methods of forming approximations: 1) fitting a simple polynomial to the signal; and 2) general linear predictive coding (LPC). I will not go into the details here, only some generalities that involve the encoding options.
</P>
<P>
First, fixed polynomial prediction (specified with <TT>-l 0</TT>) is much faster, but less accurate than LPC. The higher the maximum LPC order, the slower, but more accurate, the model will be. However, there are diminishing returns with increasing orders. Also, at some point (around order 9) the part of the encoder that guesses what is the best order to use will start to get it wrong and the compression will actually decrease slightly; at that point you will have to you will have to use the exhaustive search option <TT>-e</TT> to overcome this, which is significantly slower.
</P>
<P>
Second, the parameters for the fixed predictors can be transmitted in 3 bits whereas the parameters for the LPC model depend on the bits-per-sample and LPC order. This means the frame header length varies depending on the method and order you choose and can affect the optimal block size.
</P>
<P>
<B>RESIDUAL CODING</B>
</P>
<P>
Once the model is generated, the encoder subracts the approximation from the original signal to get the residual (error) signal. The error signal is then losslessly coded. To do this, FLAC takes advantage of the fact that the error signal generally has a Laplacian (two-sided geometric) distribution, and that there are a set of special Huffman codes called Rice codes that can be used to efficiently encode these kind of signals quickly and without needing a dictionary.
</P>
<P>
Rice coding involves finding a single parameter that matches a signal's distribution, then using that parameter to generate the codes. As the distribution changes, the optimal parameter changes, so FLAC supports a method that allows the parameter to change as needed. The residual can be broken into several <I>contexts</I> or <I>partitions</I>, each with it's own Rice parameter. <B><TT>flac</TT></B> allows you to specify how the partitioning is done with the <TT>-r</TT> option. The residual can be broken into 2^<I>n</I> partitions, by using the option <TT>-r n,n</TT>. The parameter <I>n</I> is called the <I>partition order</I>. Furthermore, the encoder can be made to search through <I>m</I> to <I>n</I> partition orders, taking the best one, by specifying <TT>-r m,n</TT>. Generally, the choice of n does not affect encoding speed but m,n does. The larger the difference between m and n, the more time it will take the encoder to search for the best order. The block size will also affect the optimal order.
</P>
<P>
<B>FRAMING</B>
</P>
<P>
An audio frame is preceded by a frame header and trailed by a frame footer. The header starts with a sync code, and contains the minimum information necessary for a decoder to play the stream, like sample rate, bits per sample, etc. It also contains the block or sample number and an 8-bit CRC of the frame header. The sync code, frame header CRC, and block/sample number allow resynchronization and seeking even in the absence of seek points. The frame footer contains a 16-bit CRC of the entire encoded frame for error detection. If the reference decoder detects a CRC error it will generate a silent block.
</P>
<P>
<B>MISCELLANEOUS</B>
</P>
<P>
In order to support come common types of metadata, the reference decoder knows how to skip ID3V1 and ID3V2 tags so it is safe to tag FLAC files in this way. ID3V2 tags must come at the beginning of the file (before the "fLaC" marker) and ID3V1 tags must come at the end of the file.
</P>
<P>
<B><TT>flac</TT></B> has a verify option <TT>-V</TT> that verifies the output while encoding. With this option, a decoder is run in parallel to the encoder and its output is compared against the original input. If a difference is found <B><TT>flac</TT></B> will stop with an error.
</P>
</FONT>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="5" CELLSPACING="5" BORDER="0">
<TR><TD>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#D3D4C5">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<A NAME="flac"><B><FONT SIZE="+2">flac</FONT></B>
</FONT></TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#EEEED4">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<P>
<B><TT>flac</TT></B> is the command-line file encoder/decoder. The input to the encoder and the output to the decoder must either be RIFF WAVE format, or raw interleaved sample data. <B><TT>flac</TT></B> only supports linear PCM samples (in other words, no A-LAW, uLAW, etc.). Another restriction (hopefully short-term) is that the input must be 8, 16, or 24 bits per sample. This is not a limitation of the FLAC format, just the reference encoder/decoder.
</P>
<P>
<B><TT>flac</TT></B> assumes that RIFF WAVE files will have the extension ".wav"; this may be overridden with a command-line option. For piped-in data, <B><TT>flac</TT></B> tries to determine the type by looking at the beginning of the file. Other than this, <B><TT>flac</TT></B> makes no assumptions about file extensions, though the convention is that FLAC files have the extension ".flac" (or ".fla" on ancient file systems like FAT-16).
</P>
<P>
Before going into the full command-line description, a few other things help to sort it out: 1) <B><TT>flac</TT></B> encodes by default, so you must use <B>-d</B> to decode; 2) the options <B><TT>-0</TT></B> .. <B><TT>-9</TT></B> that control the compression level actually are just synonyms for different groups of specific encoding options (described later) and you can get the same effect by using the same options; 3) <B><TT>flac</TT></B> behaves similarly to gzip in the way it handles input and output files.
</P>
<P>
<B><TT>flac</TT></B> will be invoked one of four ways, depending on whether you are encoding, decoding, testing, or analyzing:
<UL>
<LI>
Encoding: flac [-s] [--skip #] [-V] [<I><A HREF="#format_options"><format-options></A></I>] [<I><A HREF="#encoding_options"><encoding options></A></I>] [inputfile [...]]
</LI>
<LI>
Decoding: flac -d [-s] [--skip #] [<I><A HREF="#format_options"><format-options></A></I>] [inputfile [...]]
</LI>
<LI>
Testing: flac -t [-s] [inputfile [...]]
</LI>
<LI>
Analyzing: flac -a [-s] [--skip #] [<I><A HREF="#analysis_options"><analysis-options></A></I>] [inputfile [...]]
</LI>
</UL>
</P>
<P>
In any case, if no <TT>inputfile</TT> is specified, stdin is assumed. If only one inputfile is specified, it may be "-" for stdin. When stdin is used as input, <B><TT>flac</TT></B> will write to stdout. Otherwise <B><TT>flac</TT></B> will perform the desired operation on each input file to similarly named output files (meaning for encoding, the extension will be replaced with ".flac", or appended with ".flac" if the input file has no extension, and for decoding, the extension will be ".wav" for WAVE output and ".raw" for raw output). The original file is not deleted unless --delete-input-file is specified.
</P>
<P>
If you are encoding/decoding from stdin to a file, you should use the -o option like so:
<UL>
<LI>
flac [options] -o outputfile
</LI>
<LI>
flac -d [options] -o outputfile
</LI>
</UL>
which are better than:
<UL>
<LI>
flac [options] > outputfile
</LI>
<LI>
flac -d [options] > outputfile
</LI>
</UL>
since the former allows flac to seek backwards to write the STREAMINFO or RIFF WAVE header contents when necessary.
</P>
<P>
Also, you can force output data to go to stdout using <TT>-c</TT>.
</P>
<P>The encoding options affect the compression ratio and encoding speed. The format options are used to tell <B><TT>flac</TT></B> the arrangement of samples if the input file (or output file when decoding) is a raw file. If it is a RIFF WAVE file the format options are not needed since they are read from the WAVE header.
</P>
<P>
In test mode, <B><TT>flac</TT></B> acts just like in decode mode, except no output file is written. Both decode and test modes detect errors in the stream, but they also detect when the MD5 signature of the decoded audio does not match the stored MD5 signature, even when the bitstream is valid.
</P>
<P>
<TABLE WIDTH="100%" BORDER="0" CELLSPACING="0" CELLPADDING="0" BGCOLOR="#EEEED4"><TR><TD>
<TABLE WIDTH="100%" BORDER="1" BGCOLOR="#EEEED4">
<TR>
<TD COLSPAN="2" BGCOLOR="#D3D4C5">
<A NAME="general_options"><FONT SIZE="+1"><B>General Options</B></FONT></A>
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
<TT>-d</TT>
</TD>
<TD>
Decode (<B><TT>flac</TT></B> encodes by default). <B><TT>flac</TT></B> will exit with an exit code of <TT>1</TT> (and print a message, even in silent mode) if there were any errors during decoding, including when the MD5 checksum does not match the decoded output. Otherwise the exit code will be <TT>0</TT>.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
<TT>-t</TT>
</TD>
<TD>
Test (same as <B><TT>-d</TT></B> except no decoded file is written). The exit codes are the same as in decode mode.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
<TT>-a</TT>
</TD>
<TD>
Analyze (same as <B><TT>-d</TT></B> except an analysis file is written). The exit codes are the same as in decode mode. This option is mainly for developers; the output will be a text file that has data about each frame and subframe.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
<TT>-c</TT>
</TD>
<TD>
Write output to stdout
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
<TT>-s</TT>
</TD>
<TD>
Silent: do not show encoding/decoding statistics.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
<TT>-o filename</TT>
</TD>
<TD>
Force the output file name (usually <TT><B>flac</B></TT> just changes the extension).
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
<TT>--delete-input-file</TT>
</TD>
<TD>
Automatically delete the input file after a successful encode or decode. If there was an error (including a verify error) the input file is left intact.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
<TT>--skip #</TT>
</TD>
<TD>
Skip over the first # of samples of the input. This works for both encoding and decoding, but not testing.
</TD>
</TR>
</TABLE>
</TD></TR></TABLE>
</P>
<P>
<TABLE WIDTH="100%" BORDER="0" CELLSPACING="0" CELLPADDING="0" BGCOLOR="#EEEED4"><TR><TD>
<TABLE WIDTH="100%" BORDER="1" BGCOLOR="#EEEED4">
<TR>
<TD COLSPAN="2" BGCOLOR="#D3D4C5">
<A NAME="analysis_options"><FONT SIZE="+1"><B>Analysis Options</B></FONT></A>
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
--a-rtext
</TD>
<TD>
Includes the residual signal in the analysis file. This will make the file <B>very</B> big, much larger than even the decoded file.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
--a-rgp
</TD>
<TD>
Generates a gnuplot file for every subframe; each file will contain the residual distribution of the subframe. This will create a <B>lot</B> of files.
</TD>
</TR>
</TABLE>
</TD></TR></TABLE>
</P>
<P>
<TABLE WIDTH="100%" BORDER="0" CELLSPACING="0" CELLPADDING="0" BGCOLOR="#EEEED4"><TR><TD>
<TABLE WIDTH="100%" BORDER="1" BGCOLOR="#EEEED4">
<TR>
<TD COLSPAN="2" BGCOLOR="#D3D4C5">
<A NAME="encoding_options"><FONT SIZE="+1"><B>Encoding Options</B></FONT></A>
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
--lax
</TD>
<TD>
Allow encoder to generate non-Subset files. The resulting FLAC file may not be streamable, so you should only use this option in combination with custom encoding options meant for archival. File decoders will still be able play (and seek in) such files.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-S { # | X | #x }
</TD>
<TD>
Include a point or points in a SEEKTABLE:<BR>
<UL>
<LI>
<TT># </TT> : a specific sample number for a seek point
</LI>
<LI>
<TT>X </TT> : a placeholder point (always goes at the end of the SEEKTABLE)
</LI>
<LI>
<TT>#x</TT> : # evenly spaced seekpoints, the first being at sample 0
</LI>
</UL>
You may use many -S options; the resulting SEEKTABLE will be the unique-ified union of all such values.<BR>
With no -S options, flac defaults to '-S 100x'. Use -S- for no SEEKTABLE.<BR>
NOTE: -S #x will not work if the encoder can't determine the input size before starting.<BR>
NOTE: if you use -S # and # is >= samples in the input, there will be either no seek point entered (if the input size is determinable before encoding starts) or a placeholder point (if input size is not determinable).<BR>
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-P #
</TD>
<TD>
Tell the encoder to write a <TT>PADDING</TT> metadata block of the given length (in bytes) after the <TT>STREAMINFO</TT> block. <TT>-P 0</TT> implies no <TT>PADDING</TT> block, which is the default. This is useful if you plan to tag the file later with an <TT>APPLICATION</TT> block; instead of having to rewrite the entire file later just to insert your block, you can write directly over the <TT>PADDING</TT> block.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-b #
</TD>
<TD>
Specify the block size in samples. The default is 1152 for -l 0, otherwise 4608. Subset streams must use one of 192/576/1152/2304/4608/256/512/1024/2048/4096/8192/16384/32768. The reference encoder uses the same block size for the entire stream.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-m
</TD>
<TD>
Enable mid-side coding (only for stereo streams). Tends to increase compression by a few percent on average. For each block both the stereo pair and mid-side versions of the block will be encoded, and smallest resulting frame will be stored. Currently mid-side encoding is only available when bits-per-sample <= 16.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-M
</TD>
<TD>
Enable loose mid-side coding (only for stereo streams). Like <TT>-m</TT> but the encoder adaptively switches between independent and mid-side coding, which is faster but yields less compression than <TT>-m</TT> (which does an exhaustive search).
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-0 .. -9
</TD>
<TD>
Fastest compression .. highest compression. The default is <TT>-5</TT>.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-0
</TD>
<TD>
Synonymous with -l 0 -b 1152 -r 2,2
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-1
</TD>
<TD>
Synonymous with -l 0 -b 1152 -M -r 2,2
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-2
</TD>
<TD>
Synonymous with -l 0 -b 1152 -m -r 3
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-3
</TD>
<TD>
Synonymous with -l 6 -b 4608 -r 3,3
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-4
</TD>
<TD>
Synonymous with -l 8 -b 4608 -M -r 3,3
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-5
</TD>
<TD>
Synonymous with -l 8 -b 4608 -m -r 3,3
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-6
</TD>
<TD>
Synonymous with -l 8 -b 4608 -m -r 4
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-7
</TD>
<TD>
Synonymous with -l 8 -b 4608 -m -e -r 6
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-8
</TD>
<TD>
Synonymous with -l 12 -b 4608 -m -e -r 6
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-9
</TD>
<TD>
Synonymous with -l 32 -b 4608 -m -e -r 16 -p. This is painfully slow but gives you the maximum compression <B><TT>flac</TT></B> can do for the given block size.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-e
</TD>
<TD>
Exhaustive model search (expensive!). Normally the encoder estimates the best model to use and encodes once based on the estimate. With an exhaustive model search, the encoder will generate subframes for every order and use the smallest. If the max LPC order is high this can significantly increase the encode time but can shave off another 0.5%.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-l #
</TD>
<TD>
Specifies the maximum LPC order. This number must be <= 32. If 0, the encoder will not attempt generic linear prediction, and use only fixed predictors. Using fixed predictors is faster but usually results in files being 5-10% larger.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-q #
</TD>
<TD>
Specifies the precision of the quantized LP coefficients, in bits. The default is <B><TT>-q 0</TT></B>, which means let the encoder decide based on the signal. Unless you really know your input file it's best to leave this up to the encoder.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-p
</TD>
<TD>
Do exhaustive LP coefficient quantization optimization. This option overrides any <B><TT>-q</TT></B> option. It is expensive and typically will only improve the compression a tiny fraction of a percent. <B><TT>-q</TT></B> has no effect when <B><TT>-l 0</TT></B> is used.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-r [#,]#
</TD>
<TD>
Set the [min,]max residual partition order. The min value defaults to 0 if unspecified.<BR>
By default the encoder uses a single Rice parameter for the subframe's entire residual. With this option, the residual is iteratively partitioned into 2^min# .. 2^max# pieces, each with its own Rice parameter. Higher values of max# yield diminishing returns. The most bang for the buck is usually with <B><TT>-r 2,2</TT></B> (more for higher block sizes). This usually shaves off about 1.5%. The technique tends to peak out about when blocksize/(2^n)=128. Use <B><TT>-r 0,16</TT></B> to force the highest degree of optimization.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-R #
</TD>
<TD>
Set the Rice parameter search distance. Defaults to 0. The residual coder will search for the best Rice parameter +/- this number for each residual partition. This option is expensive (run time for -R n will typically be (2n)*30% over that of -R 0) and doesn't give much of a gain. As a matter of fact, none of the -0..-9 options currently use it since -R > 1 is not consistently better like it should be.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-V
</TD>
<TD>
Verify the encoding process. With this option, <B><TT>flac</TT></B> will create a parallel decoder that decodes the output of the encoder and compares the result against the original. It will abort immediately with an error if a mismatch occurs. <B><TT>-V</TT></B> increases the total encoding time but is guaranteed to catch any unforseen bug in the encoding process.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
</TD>
<TD>
<TT>-S-</TT>, <TT>-m-</TT>, <TT>-e-</TT>, <TT>-p-</TT>, <TT>-V-</TT>, <TT>--delete-input-file-</TT>, <TT>--lax-</TT> can all be used to turn off a particular option.
</TD>
</TR>
</TABLE>
</TD></TR></TABLE>
</P>
<P>
<TABLE WIDTH="100%" BORDER="0" CELLSPACING="0" CELLPADDING="0" BGCOLOR="#EEEED4"><TR><TD>
<TABLE WIDTH="100%" BORDER="1" BGCOLOR="#EEEED4">
<TR>
<TD COLSPAN="2" BGCOLOR="#D3D4C5">
<A NAME="format_options"><FONT SIZE="+1"><B>Format Options</B></FONT></A>
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-fb | -fl
</TD>
<TD>
Specify big-endian | little-endian byte order in the raw file.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-fc #
</TD>
<TD>
Specify the number of channels in the raw file.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-fp #
</TD>
<TD>
Specify the number of bits per sample in the raw file.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-fs #
</TD>
<TD>
Specify the sample rate of the raw file.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-fu
</TD>
<TD>
Specify that the samples in the raw file are unsigned (the default is signed).
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-fr
</TD>
<TD>
Treat the input file (or output file if decoding) as a raw file, regardless of the extension.
</TD>
</TR>
<TR>
<TD NOWRAP ALIGN="RIGHT" VALIGN="TOP" BGCOLOR="#F4F4CC">
-fw
</TD>
<TD>
Treat the input file (or output file if decoding) as a RIFF WAVE file, regardless of the extension.
</TD>
</TR>
</TABLE>
</TD></TR></TABLE>
</P>
</FONT>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="5" CELLSPACING="5" BORDER="0">
<TR><TD>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#D3D4C5">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<B><FONT SIZE="+2">metaflac</FONT></B>
</FONT></TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#EEEED4">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<P>
<B><TT>metaflac</TT></B> is the command-line <TT>.flac</TT> file metadata editor. Right now it just lists the contents of all metadata blocks in a .flac file, but soon it will allow you to insert, delete, and edit blocks.
</P>
<P>
Currently <B><TT>metaflac</TT></B> can be invoked only one way:
<UL>
<LI>
Listing: metaflac [-v] inputfile
</LI>
</UL>
</P>
<P>
<TT>inputfile</TT> may be "-" for stdin. If <TT>-v</TT> is used, you will get verbose output.
</P>
</FONT>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="5" CELLSPACING="5" BORDER="0">
<TR><TD>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#D3D4C5">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<A NAME="plugins"><B><FONT SIZE="+2">xmms plugin</FONT></B></A>
</FONT></TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#EEEED4">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<P>
All that is necessary is to copy <B><TT>libxmms-flac.so</TT></B> to the directory where XMMS looks for input plugins (usually <B><TT>/usr/lib/xmms/Input</TT></B>). There is nothing else to configure. Make sure to restart XMMS before trying to play any <TT>.flac</TT> files.
</P>
</FONT>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="5" CELLSPACING="5" BORDER="0">
<TR><TD>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#D3D4C5">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<B><FONT SIZE="+2">winamp plugin</FONT></B>
</FONT></TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#EEEED4">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<P>
All that is necessary is to copy <B><TT>in_flac.dll</TT></B> to the <B><TT>Plugins/</TT></B> directory of your Winamp installation. There is nothing else to configure. Make sure to restart Winamp before trying to play any <TT>.flac</TT> files.
</P>
</FONT>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="5" CELLSPACING="5" BORDER="0">
<TR><TD>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#D3D4C5">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<B><FONT SIZE="+2">known bugs</FONT></B>
</FONT></TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
<TABLE CELLSPACING="0" CELLPADDING="3" WIDTH="100%" BORDER="0" BGCOLOR="#EEEED4">
<TR><TD><FONT FACE="Lucida,Verdana,Helvetica,Arial">
<P>
Bug tracking is done on the Sourceforge project page <A HREF="http://sourceforge.net/bugs/?group_id=13478">here</A>. If you submit a bug, please provide an email contact and/or use the Monitor feature.
</P>
</FONT>
</TD></TR>
</TABLE>
<TABLE WIDTH="100%" CELLPADDING="0" CELLSPACING="0" BORDER="0"><TR BGCOLOR="#000000"><TD><IMG SRC="images/1x1.gif" WIDTH="1" HEIGHT="1" ALT=""></TD></TR></TABLE>
</TD></TR>
</TABLE>
</CENTER>
<P>nbsp;Copyright (c) 2000,2001 Josh Coalson</P>
</BODY>
</HTML>
|
