mlp: Split common code from parser and decoder to be used by encoder.

Originally committed as revision 14733 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 109 insertions, 0 deletions

diff --git a/libavcodec/mlp.h b/libavcodec/mlp.h
new file mode 100644
index 0000000000..43c3b272a5
--- /dev/null
+++ b/libavcodec/mlp.h
@@ -0,0 +1,109 @@
+/*
+ * MLP codec common header file
+ * Copyright (c) 2007-2008 Ian Caulfield
+ *
+ * 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
+ */
+
+#ifndef FFMPEG_MLP_H
+#define FFMPEG_MLP_H
+
+#include <stdint.h>
+
+#include "avcodec.h"
+
+/** Maximum number of channels that can be decoded. */
+#define MAX_CHANNELS        16
+
+/** Maximum number of matrices used in decoding; most streams have one matrix
+ *  per output channel, but some rematrix a channel (usually 0) more than once.
+ */
+
+#define MAX_MATRICES        15
+
+/** Maximum number of substreams that can be decoded. This could also be set
+ *  higher, but I haven't seen any examples with more than two. */
+#define MAX_SUBSTREAMS      2
+
+/** maximum sample frequency seen in files */
+#define MAX_SAMPLERATE      192000
+
+/** maximum number of audio samples within one access unit */
+#define MAX_BLOCKSIZE       (40 * (MAX_SAMPLERATE / 48000))
+/** next power of two greater than MAX_BLOCKSIZE */
+#define MAX_BLOCKSIZE_POW2  (64 * (MAX_SAMPLERATE / 48000))
+
+/** number of allowed filters */
+#define NUM_FILTERS         2
+
+/** The maximum number of taps in either the IIR or FIR filter;
+ *  I believe MLP actually specifies the maximum order for IIR filters as four,
+ *  and that the sum of the orders of both filters must be <= 8. */
+#define MAX_FILTER_ORDER    8
+
+#define FIR 0
+#define IIR 1
+
+/** filter data */
+typedef struct {
+    uint8_t     order; ///< number of taps in filter
+    uint8_t     shift; ///< Right shift to apply to output of filter.
+
+    int32_t     coeff[MAX_FILTER_ORDER];
+    int32_t     state[MAX_FILTER_ORDER];
+} FilterParams;
+
+/** sample data coding information */
+typedef struct {
+    FilterParams filter_params[NUM_FILTERS];
+
+    int16_t     huff_offset;      ///< Offset to apply to residual values.
+    int32_t     sign_huff_offset; ///< sign/rounding-corrected version of huff_offset
+    uint8_t     codebook;         ///< Which VLC codebook to use to read residuals.
+    uint8_t     huff_lsbs;        ///< Size of residual suffix not encoded using VLC.
+} ChannelParams;
+
+/** Tables defining the Huffman codes.
+ *  There are three entropy coding methods used in MLP (four if you count
+ *  "none" as a method). These use the same sequences for codes starting with
+ *  00 or 01, but have different codes starting with 1. */
+
+extern const uint8_t ff_mlp_huffman_tables[3][18][2];
+
+/** MLP uses checksums that seem to be based on the standard CRC algorithm, but
+ *  are not (in implementation terms, the table lookup and XOR are reversed).
+ *  We can implement this behavior using a standard av_crc on all but the
+ *  last element, then XOR that with the last element. */
+
+uint8_t  ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size);
+uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size);
+
+/** Calculate an 8-bit checksum over a restart header -- a non-multiple-of-8
+ *  number of bits, starting two bits into the first byte of buf. */
+
+uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size);
+
+/** XOR together all the bytes of a buffer.
+ *  Does this belong in dspcontext? */
+
+uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size);
+
+int ff_mlp_init_crc2D(AVCodecParserContext *s);
+
+void ff_mlp_init_crc();
+
+#endif /* FFMPEG_MLP_H */