From ce15710f554ef3520f968c8b4284a0f576611c95 Mon Sep 17 00:00:00 2001 From: Ramiro Polla Date: Wed, 13 Aug 2008 18:47:03 +0000 Subject: 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 --- libavcodec/mlp.h | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) create mode 100644 libavcodec/mlp.h (limited to 'libavcodec/mlp.h') 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 + +#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 */ -- cgit v1.2.3