mirror of https://github.com/FFmpeg/FFmpeg.git
decoder works great, this decoder is not completely and seamlessly integrated yet with FFmpeg Originally committed as revision 4008 to svn://svn.ffmpeg.org/ffmpeg/trunkpull/126/head
Mike Melanson
20 years ago
parent
2a515c08f2
commit
6d6d7970e7
6 changed files with 996 additions and 3 deletions
@ -0,0 +1,970 @@ |
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/*
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* ALAC (Apple Lossless Audio Codec) decoder |
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* Copyright (c) 2005 David Hammerton |
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* All rights reserved. |
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* |
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* This library is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2 of the License, or (at your option) any later version. |
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* |
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* This library is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with this library; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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/**
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* @file alac.c |
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* ALAC (Apple Lossless Audio Codec) decoder |
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* @author 2005 David Hammerton |
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* |
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* For more information on the ALAC format, visit: |
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* http://crazney.net/programs/itunes/alac.html
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* |
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* Note: This decoder expects a 36- (0x24-)byte QuickTime atom to be |
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* passed through the extradata[_size] fields. This atom is tacked onto |
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* the end of an 'alac' stsd atom and has the following format: |
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* bytes 0-3 atom size (0x24), big-endian |
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* bytes 4-7 atom type ('alac', not the 'alac' tag from start of stsd) |
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* bytes 8-35 data bytes needed by decoder |
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*/ |
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#include "avcodec.h" |
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#define ALAC_EXTRADATA_SIZE 36 |
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struct alac_file { |
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unsigned char *input_buffer; |
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int input_buffer_index; |
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int input_buffer_size; |
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int input_buffer_bitaccumulator; /* used so we can do arbitary
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bit reads */ |
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int samplesize; |
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int numchannels; |
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int bytespersample; |
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/* buffers */ |
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int32_t *predicterror_buffer_a; |
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int32_t *predicterror_buffer_b; |
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int32_t *outputsamples_buffer_a; |
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int32_t *outputsamples_buffer_b; |
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/* stuff from setinfo */ |
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uint32_t setinfo_max_samples_per_frame; /* 0x1000 = 4096 */ /* max samples per frame? */ |
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uint8_t setinfo_7a; /* 0x00 */ |
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uint8_t setinfo_sample_size; /* 0x10 */ |
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uint8_t setinfo_rice_historymult; /* 0x28 */ |
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uint8_t setinfo_rice_initialhistory; /* 0x0a */ |
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uint8_t setinfo_rice_kmodifier; /* 0x0e */ |
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uint8_t setinfo_7f; /* 0x02 */ |
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uint16_t setinfo_80; /* 0x00ff */ |
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uint32_t setinfo_82; /* 0x000020e7 */ |
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uint32_t setinfo_86; /* 0x00069fe4 */ |
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uint32_t setinfo_8a_rate; /* 0x0000ac44 */ |
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/* end setinfo stuff */ |
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}; |
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typedef struct alac_file alac_file; |
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typedef struct { |
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AVCodecContext *avctx; |
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/* init to 0; first frame decode should initialize from extradata and
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* set this to 1 */ |
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int context_initialized; |
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alac_file *alac; |
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} ALACContext; |
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static void allocate_buffers(alac_file *alac) |
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{ |
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alac->predicterror_buffer_a = av_malloc(alac->setinfo_max_samples_per_frame * 4); |
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alac->predicterror_buffer_b = av_malloc(alac->setinfo_max_samples_per_frame * 4); |
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alac->outputsamples_buffer_a = av_malloc(alac->setinfo_max_samples_per_frame * 4); |
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alac->outputsamples_buffer_b = av_malloc(alac->setinfo_max_samples_per_frame * 4); |
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} |
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void alac_set_info(alac_file *alac, char *inputbuffer) |
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{ |
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char *ptr = inputbuffer; |
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ptr += 4; /* size */ |
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ptr += 4; /* alac */ |
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ptr += 4; /* 0 ? */ |
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alac->setinfo_max_samples_per_frame = BE_32(ptr); /* buffer size / 2 ? */ |
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ptr += 4; |
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alac->setinfo_7a = *ptr++; |
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alac->setinfo_sample_size = *ptr++; |
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alac->setinfo_rice_historymult = *ptr++; |
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alac->setinfo_rice_initialhistory = *ptr++; |
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alac->setinfo_rice_kmodifier = *ptr++; |
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alac->setinfo_7f = *ptr++; |
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alac->setinfo_80 = BE_16(ptr); |
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ptr += 2; |
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alac->setinfo_82 = BE_32(ptr); |
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ptr += 4; |
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alac->setinfo_86 = BE_32(ptr); |
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ptr += 4; |
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alac->setinfo_8a_rate = BE_32(ptr); |
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ptr += 4; |
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allocate_buffers(alac); |
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} |
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/* stream reading */ |
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/* supports reading 1 to 16 bits, in big endian format */ |
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static uint32_t readbits_16(alac_file *alac, int bits) |
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{ |
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uint32_t result; |
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int new_accumulator; |
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if (alac->input_buffer_index + 2 >= alac->input_buffer_size) { |
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av_log(NULL, AV_LOG_INFO, "alac: input buffer went out of bounds (%d >= %d)\n", |
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alac->input_buffer_index + 2, alac->input_buffer_size); |
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exit (0); |
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} |
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result = (alac->input_buffer[alac->input_buffer_index + 0] << 16) | |
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(alac->input_buffer[alac->input_buffer_index + 1] << 8) | |
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(alac->input_buffer[alac->input_buffer_index + 2]); |
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/* shift left by the number of bits we've already read,
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* so that the top 'n' bits of the 24 bits we read will |
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* be the return bits */ |
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result = result << alac->input_buffer_bitaccumulator; |
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result = result & 0x00ffffff; |
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/* and then only want the top 'n' bits from that, where
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* n is 'bits' */ |
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result = result >> (24 - bits); |
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new_accumulator = (alac->input_buffer_bitaccumulator + bits); |
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/* increase the buffer pointer if we've read over n bytes. */ |
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alac->input_buffer_index += (new_accumulator >> 3); |
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/* and the remainder goes back into the bit accumulator */ |
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alac->input_buffer_bitaccumulator = (new_accumulator & 7); |
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return result; |
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} |
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/* supports reading 1 to 32 bits, in big endian format */ |
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static uint32_t readbits(alac_file *alac, int bits) |
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{ |
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int32_t result = 0; |
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if (bits > 16) { |
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bits -= 16; |
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result = readbits_16(alac, 16) << bits; |
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} |
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result |= readbits_16(alac, bits); |
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return result; |
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} |
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/* reads a single bit */ |
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static int readbit(alac_file *alac) |
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{ |
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int result; |
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int new_accumulator; |
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if (alac->input_buffer_index >= alac->input_buffer_size) { |
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av_log(NULL, AV_LOG_INFO, "alac: input buffer went out of bounds (%d >= %d)\n", |
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alac->input_buffer_index + 2, alac->input_buffer_size); |
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exit (0); |
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} |
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result = alac->input_buffer[alac->input_buffer_index]; |
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result = result << alac->input_buffer_bitaccumulator; |
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result = result >> 7 & 1; |
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new_accumulator = (alac->input_buffer_bitaccumulator + 1); |
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alac->input_buffer_index += (new_accumulator / 8); |
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alac->input_buffer_bitaccumulator = (new_accumulator % 8); |
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return result; |
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} |
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static void unreadbits(alac_file *alac, int bits) |
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{ |
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int new_accumulator = (alac->input_buffer_bitaccumulator - bits); |
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alac->input_buffer_index += (new_accumulator >> 3); |
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alac->input_buffer_bitaccumulator = (new_accumulator & 7); |
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if (alac->input_buffer_bitaccumulator < 0) |
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alac->input_buffer_bitaccumulator *= -1; |
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} |
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/* hideously inefficient. could use a bitmask search,
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* alternatively bsr on x86, |
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*/ |
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static int count_leading_zeros(int32_t input) |
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{ |
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int i = 0; |
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while (!(0x80000000 & input) && i < 32) { |
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i++; |
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input = input << 1; |
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} |
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return i; |
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} |
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void bastardized_rice_decompress(alac_file *alac, |
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int32_t *output_buffer, |
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int output_size, |
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int readsamplesize, /* arg_10 */ |
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int rice_initialhistory, /* arg424->b */ |
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int rice_kmodifier, /* arg424->d */ |
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int rice_historymult, /* arg424->c */ |
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int rice_kmodifier_mask /* arg424->e */ |
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) |
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{ |
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int output_count; |
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unsigned int history = rice_initialhistory; |
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int sign_modifier = 0; |
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for (output_count = 0; output_count < output_size; output_count++) { |
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int32_t x = 0; |
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int32_t x_modified; |
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int32_t final_val; |
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/* read x - number of 1s before 0 represent the rice */ |
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while (x <= 8 && readbit(alac)) { |
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x++; |
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} |
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if (x > 8) { /* RICE THRESHOLD */ |
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/* use alternative encoding */ |
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int32_t value; |
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value = readbits(alac, readsamplesize); |
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/* mask value to readsamplesize size */ |
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if (readsamplesize != 32) |
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value &= (0xffffffff >> (32 - readsamplesize)); |
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x = value; |
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} else { |
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/* standard rice encoding */ |
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int extrabits; |
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int k; /* size of extra bits */ |
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/* read k, that is bits as is */ |
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k = 31 - rice_kmodifier - count_leading_zeros((history >> 9) + 3); |
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if (k < 0)
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k += rice_kmodifier; |
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else
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k = rice_kmodifier; |
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if (k != 1) { |
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extrabits = readbits(alac, k); |
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/* multiply x by 2^k - 1, as part of their strange algorithm */ |
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x = (x << k) - x; |
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if (extrabits > 1) { |
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x += extrabits - 1; |
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} else
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unreadbits(alac, 1); |
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} |
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} |
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x_modified = sign_modifier + x; |
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final_val = (x_modified + 1) / 2; |
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if (x_modified & 1) final_val *= -1; |
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output_buffer[output_count] = final_val; |
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sign_modifier = 0; |
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/* now update the history */ |
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history += (x_modified * rice_historymult) |
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- ((history * rice_historymult) >> 9); |
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if (x_modified > 0xffff) |
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history = 0xffff; |
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/* special case: there may be compressed blocks of 0 */ |
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if ((history < 128) && (output_count+1 < output_size)) { |
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int block_size; |
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sign_modifier = 1; |
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x = 0; |
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while (x <= 8 && readbit(alac)) { |
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x++; |
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} |
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if (x > 8) { |
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block_size = readbits(alac, 16); |
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block_size &= 0xffff; |
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} else { |
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int k; |
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int extrabits; |
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k = count_leading_zeros(history) + ((history + 16) >> 6 /* / 64 */) - 24; |
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extrabits = readbits(alac, k); |
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block_size = (((1 << k) - 1) & rice_kmodifier_mask) * x |
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+ extrabits - 1; |
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if (extrabits < 2) { |
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x = 1 - extrabits; |
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block_size += x; |
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unreadbits(alac, 1); |
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} |
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} |
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if (block_size > 0) { |
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memset(&output_buffer[output_count+1], 0, block_size * 4); |
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output_count += block_size; |
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} |
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if (block_size > 0xffff) |
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sign_modifier = 0; |
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history = 0; |
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} |
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} |
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} |
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#define SIGN_EXTENDED32(val, bits) ((val << (32 - bits)) >> (32 - bits)) |
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#define SIGN_ONLY(v) \ |
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((v < 0) ? (-1) : \
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((v > 0) ? (1) : \
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(0))) |
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static void predictor_decompress_fir_adapt(int32_t *error_buffer, |
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int32_t *buffer_out, |
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int output_size, |
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int readsamplesize, |
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int16_t *predictor_coef_table, |
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int predictor_coef_num, |
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int predictor_quantitization) |
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{ |
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int i; |
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/* first sample always copies */ |
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*buffer_out = *error_buffer; |
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if (!predictor_coef_num) { |
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if (output_size <= 1) return; |
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memcpy(buffer_out+1, error_buffer+1, (output_size-1) * 4); |
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return; |
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} |
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if (predictor_coef_num == 0x1f) { /* 11111 - max value of predictor_coef_num */ |
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/* second-best case scenario for fir decompression,
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* error describes a small difference from the previous sample only |
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*/ |
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if (output_size <= 1) return; |
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for (i = 0; i < output_size - 1; i++) { |
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int32_t prev_value; |
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int32_t error_value; |
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prev_value = buffer_out[i]; |
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error_value = error_buffer[i+1]; |
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buffer_out[i+1] = SIGN_EXTENDED32((prev_value + error_value), readsamplesize); |
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} |
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return; |
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} |
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/* read warm-up samples */ |
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if (predictor_coef_num > 0) { |
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int i; |
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for (i = 0; i < predictor_coef_num; i++) { |
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int32_t val; |
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val = buffer_out[i] + error_buffer[i+1]; |
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val = SIGN_EXTENDED32(val, readsamplesize); |
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buffer_out[i+1] = val; |
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} |
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} |
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#if 0 |
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/* 4 and 8 are very common cases (the only ones i've seen). these
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* should be unrolled and optimised |
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*/ |
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if (predictor_coef_num == 4) { |
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/* FIXME: optimised general case */ |
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return; |
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} |
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if (predictor_coef_table == 8) { |
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/* FIXME: optimised general case */ |
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return; |
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} |
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#endif |
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/* general case */ |
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if (predictor_coef_num > 0) { |
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for (i = predictor_coef_num + 1; |
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i < output_size; |
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i++) { |
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int j; |
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int sum = 0; |
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int outval; |
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int error_val = error_buffer[i]; |
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for (j = 0; j < predictor_coef_num; j++) { |
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sum += (buffer_out[predictor_coef_num-j] - buffer_out[0]) * |
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predictor_coef_table[j]; |
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} |
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outval = (1 << (predictor_quantitization-1)) + sum; |
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outval = outval >> predictor_quantitization; |
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outval = outval + buffer_out[0] + error_val; |
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outval = SIGN_EXTENDED32(outval, readsamplesize); |
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buffer_out[predictor_coef_num+1] = outval; |
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if (error_val > 0) { |
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int predictor_num = predictor_coef_num - 1; |
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while (predictor_num >= 0 && error_val > 0) { |
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int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num]; |
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int sign = SIGN_ONLY(val); |
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predictor_coef_table[predictor_num] -= sign; |
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val *= sign; /* absolute value */ |
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error_val -= ((val >> predictor_quantitization) * |
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(predictor_coef_num - predictor_num)); |
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predictor_num--; |
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} |
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} else if (error_val < 0) { |
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int predictor_num = predictor_coef_num - 1; |
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while (predictor_num >= 0 && error_val < 0) { |
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int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num]; |
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int sign = - SIGN_ONLY(val); |
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predictor_coef_table[predictor_num] -= sign; |
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val *= sign; /* neg value */ |
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error_val -= ((val >> predictor_quantitization) * |
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(predictor_coef_num - predictor_num)); |
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predictor_num--; |
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} |
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} |
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buffer_out++; |
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} |
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} |
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} |
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void deinterlace_16(int32_t *buffer_a, int32_t *buffer_b, |
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int16_t *buffer_out, |
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int numchannels, int numsamples, |
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uint8_t interlacing_shift, |
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uint8_t interlacing_leftweight) { |
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int i; |
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if (numsamples <= 0) return; |
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/* weighted interlacing */ |
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if (interlacing_leftweight) { |
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for (i = 0; i < numsamples; i++) { |
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int32_t difference, midright; |
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int16_t left; |
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int16_t right; |
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midright = buffer_a[i]; |
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difference = buffer_b[i]; |
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right = midright - ((difference * interlacing_leftweight) >> interlacing_shift); |
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left = (midright - ((difference * interlacing_leftweight) >> interlacing_shift)) |
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+ difference; |
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/* output is always little endian */ |
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/*
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if (host_bigendian) { |
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be2me_16(left); |
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be2me_16(right); |
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} |
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*/ |
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buffer_out[i*numchannels] = left; |
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buffer_out[i*numchannels + 1] = right; |
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} |
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return; |
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} |
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/* otherwise basic interlacing took place */ |
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for (i = 0; i < numsamples; i++) { |
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int16_t left, right; |
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left = buffer_a[i]; |
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right = buffer_b[i]; |
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/* output is always little endian */ |
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/*
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if (host_bigendian) { |
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be2me_16(left); |
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be2me_16(right); |
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} |
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*/ |
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buffer_out[i*numchannels] = left; |
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buffer_out[i*numchannels + 1] = right; |
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} |
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} |
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int decode_frame(ALACContext *s, alac_file *alac, |
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unsigned char *inbuffer, |
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int input_buffer_size, |
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void *outbuffer, int *outputsize){ |
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|
||||
int channels; |
||||
int32_t outputsamples = alac->setinfo_max_samples_per_frame; |
||||
|
||||
/* initialize from the extradata */ |
||||
if (!s->context_initialized) { |
||||
if (s->avctx->extradata_size != ALAC_EXTRADATA_SIZE) { |
||||
av_log(NULL, AV_LOG_ERROR, "alac: expected %d extradata bytes\n",
|
||||
ALAC_EXTRADATA_SIZE); |
||||
return input_buffer_size; |
||||
} |
||||
alac_set_info(s->alac, s->avctx->extradata); |
||||
s->context_initialized = 1; |
||||
} |
||||
|
||||
|
||||
/* setup the stream */ |
||||
alac->input_buffer = inbuffer; |
||||
alac->input_buffer_index = 0; |
||||
alac->input_buffer_size = input_buffer_size; |
||||
alac->input_buffer_bitaccumulator = 0; |
||||
|
||||
channels = readbits(alac, 3); |
||||
|
||||
*outputsize = outputsamples * alac->bytespersample; |
||||
|
||||
switch(channels) { |
||||
case 0: { /* 1 channel */ |
||||
int hassize; |
||||
int isnotcompressed; |
||||
int readsamplesize; |
||||
|
||||
int wasted_bytes; |
||||
int ricemodifier; |
||||
|
||||
|
||||
/* 2^result = something to do with output waiting.
|
||||
* perhaps matters if we read > 1 frame in a pass? |
||||
*/ |
||||
readbits(alac, 4); |
||||
|
||||
readbits(alac, 12); /* unknown, skip 12 bits */ |
||||
|
||||
hassize = readbits(alac, 1); /* the output sample size is stored soon */ |
||||
|
||||
wasted_bytes = readbits(alac, 2); /* unknown ? */ |
||||
|
||||
isnotcompressed = readbits(alac, 1); /* whether the frame is compressed */ |
||||
|
||||
if (hassize) { |
||||
/* now read the number of samples,
|
||||
* as a 32bit integer */ |
||||
outputsamples = readbits(alac, 32); |
||||
*outputsize = outputsamples * alac->bytespersample; |
||||
} |
||||
|
||||
readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8); |
||||
|
||||
if (!isnotcompressed) { |
||||
/* so it is compressed */ |
||||
int16_t predictor_coef_table[32]; |
||||
int predictor_coef_num; |
||||
int prediction_type; |
||||
int prediction_quantitization; |
||||
int i; |
||||
|
||||
/* skip 16 bits, not sure what they are. seem to be used in
|
||||
* two channel case */ |
||||
readbits(alac, 8); |
||||
readbits(alac, 8); |
||||
|
||||
prediction_type = readbits(alac, 4); |
||||
prediction_quantitization = readbits(alac, 4); |
||||
|
||||
ricemodifier = readbits(alac, 3); |
||||
predictor_coef_num = readbits(alac, 5); |
||||
|
||||
/* read the predictor table */ |
||||
for (i = 0; i < predictor_coef_num; i++) { |
||||
predictor_coef_table[i] = (int16_t)readbits(alac, 16); |
||||
} |
||||
|
||||
if (wasted_bytes) { |
||||
/* these bytes seem to have something to do with
|
||||
* > 2 channel files. |
||||
*/ |
||||
av_log(NULL, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n"); |
||||
} |
||||
|
||||
bastardized_rice_decompress(alac, |
||||
alac->predicterror_buffer_a, |
||||
outputsamples, |
||||
readsamplesize, |
||||
alac->setinfo_rice_initialhistory, |
||||
alac->setinfo_rice_kmodifier, |
||||
ricemodifier * alac->setinfo_rice_historymult / 4, |
||||
(1 << alac->setinfo_rice_kmodifier) - 1); |
||||
|
||||
if (prediction_type == 0) { |
||||
/* adaptive fir */ |
||||
predictor_decompress_fir_adapt(alac->predicterror_buffer_a, |
||||
alac->outputsamples_buffer_a, |
||||
outputsamples, |
||||
readsamplesize, |
||||
predictor_coef_table, |
||||
predictor_coef_num, |
||||
prediction_quantitization); |
||||
} else { |
||||
av_log(NULL, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type); |
||||
/* i think the only other prediction type (or perhaps this is just a
|
||||
* boolean?) runs adaptive fir twice.. like: |
||||
* predictor_decompress_fir_adapt(predictor_error, tempout, ...) |
||||
* predictor_decompress_fir_adapt(predictor_error, outputsamples ...) |
||||
* little strange.. |
||||
*/ |
||||
} |
||||
|
||||
} else { |
||||
/* not compressed, easy case */ |
||||
if (readsamplesize <= 16) { |
||||
int i; |
||||
for (i = 0; i < outputsamples; i++) { |
||||
int32_t audiobits = readbits(alac, readsamplesize); |
||||
|
||||
audiobits = SIGN_EXTENDED32(audiobits, readsamplesize); |
||||
|
||||
alac->outputsamples_buffer_a[i] = audiobits; |
||||
} |
||||
} else { |
||||
int i; |
||||
for (i = 0; i < outputsamples; i++) { |
||||
int32_t audiobits; |
||||
|
||||
audiobits = readbits(alac, 16); |
||||
/* special case of sign extension..
|
||||
* as we'll be ORing the low 16bits into this */ |
||||
audiobits = audiobits << 16; |
||||
audiobits = audiobits >> (32 - readsamplesize); |
||||
|
||||
audiobits |= readbits(alac, readsamplesize - 16); |
||||
|
||||
alac->outputsamples_buffer_a[i] = audiobits; |
||||
} |
||||
} |
||||
/* wasted_bytes = 0; // unused */ |
||||
} |
||||
|
||||
switch(alac->setinfo_sample_size) { |
||||
case 16: { |
||||
int i; |
||||
for (i = 0; i < outputsamples; i++) { |
||||
int16_t sample = alac->outputsamples_buffer_a[i]; |
||||
be2me_16(sample); |
||||
((int16_t*)outbuffer)[i * alac->numchannels] = sample; |
||||
} |
||||
break; |
||||
} |
||||
case 20: |
||||
case 24: |
||||
case 32: |
||||
av_log(NULL, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size); |
||||
break; |
||||
default: |
||||
break; |
||||
} |
||||
break; |
||||
} |
||||
case 1: { /* 2 channels */ |
||||
int hassize; |
||||
int isnotcompressed; |
||||
int readsamplesize; |
||||
|
||||
int wasted_bytes; |
||||
|
||||
uint8_t interlacing_shift; |
||||
uint8_t interlacing_leftweight; |
||||
|
||||
/* 2^result = something to do with output waiting.
|
||||
* perhaps matters if we read > 1 frame in a pass? |
||||
*/ |
||||
readbits(alac, 4); |
||||
|
||||
readbits(alac, 12); /* unknown, skip 12 bits */ |
||||
|
||||
hassize = readbits(alac, 1); /* the output sample size is stored soon */ |
||||
|
||||
wasted_bytes = readbits(alac, 2); /* unknown ? */ |
||||
|
||||
isnotcompressed = readbits(alac, 1); /* whether the frame is compressed */ |
||||
|
||||
if (hassize) { |
||||
/* now read the number of samples,
|
||||
* as a 32bit integer */ |
||||
outputsamples = readbits(alac, 32); |
||||
*outputsize = outputsamples * alac->bytespersample; |
||||
} |
||||
|
||||
readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8) + 1; |
||||
|
||||
if (!isnotcompressed) { |
||||
/* compressed */ |
||||
int16_t predictor_coef_table_a[32]; |
||||
int predictor_coef_num_a; |
||||
int prediction_type_a; |
||||
int prediction_quantitization_a; |
||||
int ricemodifier_a; |
||||
|
||||
int16_t predictor_coef_table_b[32]; |
||||
int predictor_coef_num_b; |
||||
int prediction_type_b; |
||||
int prediction_quantitization_b; |
||||
int ricemodifier_b; |
||||
|
||||
int i; |
||||
|
||||
interlacing_shift = readbits(alac, 8); |
||||
interlacing_leftweight = readbits(alac, 8); |
||||
|
||||
/******** channel 1 ***********/ |
||||
prediction_type_a = readbits(alac, 4); |
||||
prediction_quantitization_a = readbits(alac, 4); |
||||
|
||||
ricemodifier_a = readbits(alac, 3); |
||||
predictor_coef_num_a = readbits(alac, 5); |
||||
|
||||
/* read the predictor table */ |
||||
for (i = 0; i < predictor_coef_num_a; i++) { |
||||
predictor_coef_table_a[i] = (int16_t)readbits(alac, 16); |
||||
} |
||||
|
||||
/******** channel 2 *********/ |
||||
prediction_type_b = readbits(alac, 4); |
||||
prediction_quantitization_b = readbits(alac, 4); |
||||
|
||||
ricemodifier_b = readbits(alac, 3); |
||||
predictor_coef_num_b = readbits(alac, 5); |
||||
|
||||
/* read the predictor table */ |
||||
for (i = 0; i < predictor_coef_num_b; i++) { |
||||
predictor_coef_table_b[i] = (int16_t)readbits(alac, 16); |
||||
} |
||||
|
||||
/*********************/ |
||||
if (wasted_bytes) { |
||||
/* see mono case */ |
||||
av_log(NULL, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n"); |
||||
} |
||||
|
||||
/* channel 1 */ |
||||
bastardized_rice_decompress(alac, |
||||
alac->predicterror_buffer_a, |
||||
outputsamples, |
||||
readsamplesize, |
||||
alac->setinfo_rice_initialhistory, |
||||
alac->setinfo_rice_kmodifier, |
||||
ricemodifier_a * alac->setinfo_rice_historymult / 4, |
||||
(1 << alac->setinfo_rice_kmodifier) - 1); |
||||
|
||||
if (prediction_type_a == 0) { |
||||
/* adaptive fir */ |
||||
predictor_decompress_fir_adapt(alac->predicterror_buffer_a, |
||||
alac->outputsamples_buffer_a, |
||||
outputsamples, |
||||
readsamplesize, |
||||
predictor_coef_table_a, |
||||
predictor_coef_num_a, |
||||
prediction_quantitization_a); |
||||
} else { |
||||
/* see mono case */ |
||||
av_log(NULL, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type_a); |
||||
} |
||||
|
||||
/* channel 2 */ |
||||
bastardized_rice_decompress(alac, |
||||
alac->predicterror_buffer_b, |
||||
outputsamples, |
||||
readsamplesize, |
||||
alac->setinfo_rice_initialhistory, |
||||
alac->setinfo_rice_kmodifier, |
||||
ricemodifier_b * alac->setinfo_rice_historymult / 4, |
||||
(1 << alac->setinfo_rice_kmodifier) - 1); |
||||
|
||||
if (prediction_type_b == 0) { |
||||
/* adaptive fir */ |
||||
predictor_decompress_fir_adapt(alac->predicterror_buffer_b, |
||||
alac->outputsamples_buffer_b, |
||||
outputsamples, |
||||
readsamplesize, |
||||
predictor_coef_table_b, |
||||
predictor_coef_num_b, |
||||
prediction_quantitization_b); |
||||
} else { |
||||
av_log(NULL, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type_b); |
||||
} |
||||
} else {
|
||||
/* not compressed, easy case */ |
||||
if (alac->setinfo_sample_size <= 16) { |
||||
int i; |
||||
for (i = 0; i < outputsamples; i++) { |
||||
int32_t audiobits_a, audiobits_b; |
||||
|
||||
audiobits_a = readbits(alac, alac->setinfo_sample_size); |
||||
audiobits_b = readbits(alac, alac->setinfo_sample_size); |
||||
|
||||
audiobits_a = SIGN_EXTENDED32(audiobits_a, alac->setinfo_sample_size); |
||||
audiobits_b = SIGN_EXTENDED32(audiobits_b, alac->setinfo_sample_size); |
||||
|
||||
alac->outputsamples_buffer_a[i] = audiobits_a; |
||||
alac->outputsamples_buffer_b[i] = audiobits_b; |
||||
} |
||||
} else { |
||||
int i; |
||||
for (i = 0; i < outputsamples; i++) { |
||||
int32_t audiobits_a, audiobits_b; |
||||
|
||||
audiobits_a = readbits(alac, 16); |
||||
audiobits_a = audiobits_a << 16; |
||||
audiobits_a = audiobits_a >> (32 - alac->setinfo_sample_size); |
||||
audiobits_a |= readbits(alac, alac->setinfo_sample_size - 16); |
||||
|
||||
audiobits_b = readbits(alac, 16); |
||||
audiobits_b = audiobits_b << 16; |
||||
audiobits_b = audiobits_b >> (32 - alac->setinfo_sample_size); |
||||
audiobits_b |= readbits(alac, alac->setinfo_sample_size - 16); |
||||
|
||||
alac->outputsamples_buffer_a[i] = audiobits_a; |
||||
alac->outputsamples_buffer_b[i] = audiobits_b; |
||||
} |
||||
} |
||||
/* wasted_bytes = 0; */ |
||||
interlacing_shift = 0; |
||||
interlacing_leftweight = 0; |
||||
} |
||||
|
||||
switch(alac->setinfo_sample_size) { |
||||
case 16: { |
||||
deinterlace_16(alac->outputsamples_buffer_a, |
||||
alac->outputsamples_buffer_b, |
||||
(int16_t*)outbuffer, |
||||
alac->numchannels, |
||||
outputsamples, |
||||
interlacing_shift, |
||||
interlacing_leftweight); |
||||
break; |
||||
} |
||||
case 20: |
||||
case 24: |
||||
case 32: |
||||
av_log(NULL, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size); |
||||
break; |
||||
default: |
||||
break; |
||||
} |
||||
|
||||
break; |
||||
} |
||||
} |
||||
|
||||
av_log(NULL, AV_LOG_INFO, "buf size = %d, consumed %d\n", |
||||
input_buffer_size, alac->input_buffer_index); |
||||
|
||||
/* avoid infinite loop: if decoder consumed 0 bytes; report all bytes
|
||||
* consumed */ |
||||
// if (alac->input_buffer_index)
|
||||
// return alac->input_buffer_index;
|
||||
// else
|
||||
return input_buffer_size; |
||||
} |
||||
|
||||
static int alac_decode_init(AVCodecContext * avctx) |
||||
{ |
||||
ALACContext *s = avctx->priv_data; |
||||
s->avctx = avctx; |
||||
s->context_initialized = 0; |
||||
|
||||
s->alac = av_malloc(sizeof(alac_file)); |
||||
|
||||
s->alac->samplesize = s->avctx->bits_per_sample; |
||||
s->alac->numchannels = s->avctx->channels; |
||||
s->alac->bytespersample = (s->alac->samplesize / 8) * s->alac->numchannels; |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
static int alac_decode_frame(AVCodecContext *avctx, |
||||
void *data, int *data_size, |
||||
uint8_t *buf, int buf_size) |
||||
{ |
||||
ALACContext *s = avctx->priv_data; |
||||
int bytes_consumed = buf_size; |
||||
|
||||
if (buf) |
||||
bytes_consumed = decode_frame(s, s->alac, buf, buf_size,
|
||||
data, data_size); |
||||
|
||||
return bytes_consumed; |
||||
} |
||||
|
||||
static int alac_decode_close(AVCodecContext *avctx) |
||||
{ |
||||
ALACContext *s = avctx->priv_data; |
||||
|
||||
av_free(s->alac->predicterror_buffer_a); |
||||
av_free(s->alac->predicterror_buffer_b); |
||||
|
||||
av_free(s->alac->outputsamples_buffer_a); |
||||
av_free(s->alac->outputsamples_buffer_b); |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
AVCodec alac_decoder = { |
||||
"alac", |
||||
CODEC_TYPE_AUDIO, |
||||
CODEC_ID_ALAC, |
||||
sizeof(ALACContext), |
||||
alac_decode_init, |
||||
NULL, |
||||
alac_decode_close, |
||||
alac_decode_frame, |
||||
}; |
||||
Loading…
Reference in new issue