/* * RIFF codec tags * Copyright (c) 2000 Fabrice Bellard. * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavcodec/avcodec.h" #include "avformat.h" #include "riff.h" /* Note: when encoding, the first matching tag is used, so order is important if multiple tags possible for a given codec. */ const AVCodecTag codec_bmp_tags[] = { { CODEC_ID_H264, MKTAG('H', '2', '6', '4') }, { CODEC_ID_H264, MKTAG('h', '2', '6', '4') }, { CODEC_ID_H264, MKTAG('X', '2', '6', '4') }, { CODEC_ID_H264, MKTAG('x', '2', '6', '4') }, { CODEC_ID_H264, MKTAG('a', 'v', 'c', '1') }, { CODEC_ID_H264, MKTAG('V', 'S', 'S', 'H') }, { CODEC_ID_H263, MKTAG('H', '2', '6', '3') }, { CODEC_ID_H263P, MKTAG('H', '2', '6', '3') }, { CODEC_ID_H263I, MKTAG('I', '2', '6', '3') }, /* intel h263 */ { CODEC_ID_H261, MKTAG('H', '2', '6', '1') }, { CODEC_ID_H263P, MKTAG('U', '2', '6', '3') }, { CODEC_ID_H263P, MKTAG('v', 'i', 'v', '1') }, { CODEC_ID_MPEG4, MKTAG('F', 'M', 'P', '4') }, { CODEC_ID_MPEG4, MKTAG('D', 'I', 'V', 'X') }, { CODEC_ID_MPEG4, MKTAG('D', 'X', '5', '0') }, { CODEC_ID_MPEG4, MKTAG('X', 'V', 'I', 'D') }, { CODEC_ID_MPEG4, MKTAG('M', 'P', '4', 'S') }, { CODEC_ID_MPEG4, MKTAG('M', '4', 'S', '2') }, { CODEC_ID_MPEG4, MKTAG( 4 , 0 , 0 , 0 ) }, /* some broken avi use this */ { CODEC_ID_MPEG4, MKTAG('D', 'I', 'V', '1') }, { CODEC_ID_MPEG4, MKTAG('B', 'L', 'Z', '0') }, { CODEC_ID_MPEG4, MKTAG('m', 'p', '4', 'v') }, { CODEC_ID_MPEG4, MKTAG('U', 'M', 'P', '4') }, { CODEC_ID_MPEG4, MKTAG('W', 'V', '1', 'F') }, { CODEC_ID_MPEG4, MKTAG('S', 'E', 'D', 'G') }, { CODEC_ID_MPEG4, MKTAG('R', 'M', 'P', '4') }, { CODEC_ID_MPEG4, MKTAG('3', 'I', 'V', '2') }, { CODEC_ID_MSMPEG4V3, MKTAG('D', 'I', 'V', '3') }, /* default signature when using MSMPEG4 */ { CODEC_ID_MSMPEG4V3, MKTAG('M', 'P', '4', '3') }, { CODEC_ID_MSMPEG4V3, MKTAG('M', 'P', 'G', '3') }, { CODEC_ID_MSMPEG4V3, MKTAG('D', 'I', 'V', '5') }, { CODEC_ID_MSMPEG4V3, MKTAG('D', 'I', 'V', '6') }, { CODEC_ID_MSMPEG4V3, MKTAG('D', 'I', 'V', '4') }, { CODEC_ID_MSMPEG4V3, MKTAG('A', 'P', '4', '1') }, { CODEC_ID_MSMPEG4V3, MKTAG('C', 'O', 'L', '1') }, { CODEC_ID_MSMPEG4V3, MKTAG('C', 'O', 'L', '0') }, { CODEC_ID_MSMPEG4V2, MKTAG('M', 'P', '4', '2') }, { CODEC_ID_MSMPEG4V2, MKTAG('D', 'I', 'V', '2') }, { CODEC_ID_MSMPEG4V1, MKTAG('M', 'P', 'G', '4') }, { CODEC_ID_WMV1, MKTAG('W', 'M', 'V', '1') }, { CODEC_ID_WMV2, MKTAG('W', 'M', 'V', '2') }, { CODEC_ID_DVVIDEO, MKTAG('d', 'v', 's', 'd') }, { CODEC_ID_DVVIDEO, MKTAG('d', 'v', 'h', 'd') }, { CODEC_ID_DVVIDEO, MKTAG('d', 'v', 's', 'l') }, { CODEC_ID_DVVIDEO, MKTAG('d', 'v', '2', '5') }, { CODEC_ID_DVVIDEO, MKTAG('d', 'v', '5', '0') }, { CODEC_ID_DVVIDEO, MKTAG('c', 'd', 'v', 'c') }, /* Canopus DV */ { CODEC_ID_MPEG1VIDEO, MKTAG('m', 'p', 'g', '1') }, { CODEC_ID_MPEG1VIDEO, MKTAG('m', 'p', 'g', '2') }, { CODEC_ID_MPEG2VIDEO, MKTAG('m', 'p', 'g', '2') }, { CODEC_ID_MPEG2VIDEO, MKTAG('M', 'P', 'E', 'G') }, { CODEC_ID_MPEG1VIDEO, MKTAG('P', 'I', 'M', '1') }, { CODEC_ID_MPEG1VIDEO, MKTAG('V', 'C', 'R', '2') }, { CODEC_ID_MPEG1VIDEO, MKTAG( 1 , 0 , 0 , 16) }, { CODEC_ID_MPEG2VIDEO, MKTAG( 2 , 0 , 0 , 16) }, { CODEC_ID_MPEG2VIDEO, MKTAG('D', 'V', 'R', ' ') }, { CODEC_ID_MPEG2VIDEO, MKTAG('M', 'M', 'E', 'S') }, { CODEC_ID_MJPEG, MKTAG('M', 'J', 'P', 'G') }, { CODEC_ID_MJPEG, MKTAG('L', 'J', 'P', 'G') }, { CODEC_ID_LJPEG, MKTAG('L', 'J', 'P', 'G') }, { CODEC_ID_MJPEG, MKTAG('J', 'P', 'G', 'L') }, /* Pegasus lossless JPEG */ { CODEC_ID_JPEGLS, MKTAG('M', 'J', 'L', 'S') }, /* JPEG-LS custom FOURCC for avi - encoder */ { CODEC_ID_MJPEG, MKTAG('M', 'J', 'L', 'S') }, /* JPEG-LS custom FOURCC for avi - decoder */ { CODEC_ID_MJPEG, MKTAG('j', 'p', 'e', 'g') }, { CODEC_ID_MJPEG, MKTAG('I', 'J', 'P', 'G') }, { CODEC_ID_MJPEG, MKTAG('A', 'V', 'R', 'n') }, { CODEC_ID_HUFFYUV, MKTAG('H', 'F', 'Y', 'U') }, { CODEC_ID_FFVHUFF, MKTAG('F', 'F', 'V', 'H') }, { CODEC_ID_CYUV, MKTAG('C', 'Y', 'U', 'V') }, { CODEC_ID_RAWVIDEO, MKTAG( 0 , 0 , 0 , 0 ) }, { CODEC_ID_RAWVIDEO, MKTAG('I', '4', '2', '0') }, { CODEC_ID_RAWVIDEO, MKTAG('Y', 'U', 'Y', '2') }, { CODEC_ID_RAWVIDEO, MKTAG('Y', '4', '2', '2') }, { CODEC_ID_RAWVIDEO, MKTAG('Y', 'V', '1', '2') }, { CODEC_ID_RAWVIDEO, MKTAG('U', 'Y', 'V', 'Y') }, { CODEC_ID_RAWVIDEO, MKTAG('I', 'Y', 'U', 'V') }, { CODEC_ID_RAWVIDEO, MKTAG('Y', '8', '0', '0') }, { CODEC_ID_RAWVIDEO, MKTAG('H', 'D', 'Y', 'C') }, { CODEC_ID_INDEO3, MKTAG('I', 'V', '3', '1') }, { CODEC_ID_INDEO3, MKTAG('I', 'V', '3', '2') }, { CODEC_ID_INDEO4, MKTAG('I', 'V', '4', '1') }, { CODEC_ID_INDEO5, MKTAG('I', 'V', '5', '0') }, { CODEC_ID_VP3, MKTAG('V', 'P', '3', '1') }, { CODEC_ID_VP3, MKTAG('V', 'P', '3', '0') }, { CODEC_ID_VP5, MKTAG('V', 'P', '5', '0') }, { CODEC_ID_VP6, MKTAG('V', 'P', '6', '0') }, { CODEC_ID_VP6, MKTAG('V', 'P', '6', '1') }, { CODEC_ID_VP6, MKTAG('V', 'P', '6', '2') }, { CODEC_ID_ASV1, MKTAG('A', 'S', 'V', '1') }, { CODEC_ID_ASV2, MKTAG('A', 'S', 'V', '2') }, { CODEC_ID_VCR1, MKTAG('V', 'C', 'R', '1') }, { CODEC_ID_FFV1, MKTAG('F', 'F', 'V', '1') }, { CODEC_ID_XAN_WC4, MKTAG('X', 'x', 'a', 'n') }, { CODEC_ID_MSRLE, MKTAG('m', 'r', 'l', 'e') }, { CODEC_ID_MSRLE, MKTAG( 1 , 0 , 0 , 0 ) }, { CODEC_ID_MSVIDEO1, MKTAG('M', 'S', 'V', 'C') }, { CODEC_ID_MSVIDEO1, MKTAG('m', 's', 'v', 'c') }, { CODEC_ID_MSVIDEO1, MKTAG('C', 'R', 'A', 'M') }, { CODEC_ID_MSVIDEO1, MKTAG('c', 'r', 'a', 'm') }, { CODEC_ID_MSVIDEO1, MKTAG('W', 'H', 'A', 'M') }, { CODEC_ID_MSVIDEO1, MKTAG('w', 'h', 'a', 'm') }, { CODEC_ID_CINEPAK, MKTAG('c', 'v', 'i', 'd') }, { CODEC_ID_TRUEMOTION1, MKTAG('D', 'U', 'C', 'K') }, { CODEC_ID_MSZH, MKTAG('M', 'S', 'Z', 'H') }, { CODEC_ID_ZLIB, MKTAG('Z', 'L', 'I', 'B') }, { CODEC_ID_SNOW, MKTAG('S', 'N', 'O', 'W') }, { CODEC_ID_4XM, MKTAG('4', 'X', 'M', 'V') }, { CODEC_ID_FLV1, MKTAG('F', 'L', 'V', '1') }, { CODEC_ID_FLASHSV, MKTAG('F', 'S', 'V', '1') }, { CODEC_ID_VP6F, MKTAG('V', 'P', '6', 'F') }, { CODEC_ID_SVQ1, MKTAG('s', 'v', 'q', '1') }, { CODEC_ID_TSCC, MKTAG('t', 's', 'c', 'c') }, { CODEC_ID_ULTI, MKTAG('U', 'L', 'T', 'I') }, { CODEC_ID_VIXL, MKTAG('V', 'I', 'X', 'L') }, { CODEC_ID_QPEG, MKTAG('Q', 'P', 'E', 'G') }, { CODEC_ID_QPEG, MKTAG('Q', '1', '.', '0') }, { CODEC_ID_QPEG, MKTAG('Q', '1', '.', '1') }, { CODEC_ID_WMV3, MKTAG('W', 'M', 'V', '3') }, { CODEC_ID_VC1, MKTAG('W', 'V', 'C', '1') }, { CODEC_ID_VC1, MKTAG('W', 'M', 'V', 'A') }, { CODEC_ID_LOCO, MKTAG('L', 'O', 'C', 'O') }, { CODEC_ID_WNV1, MKTAG('W', 'N', 'V', '1') }, { CODEC_ID_AASC, MKTAG('A', 'A', 'S', 'C') }, { CODEC_ID_INDEO2, MKTAG('R', 'T', '2', '1') }, { CODEC_ID_FRAPS, MKTAG('F', 'P', 'S', '1') }, { CODEC_ID_THEORA, MKTAG('t', 'h', 'e', 'o') }, { CODEC_ID_TRUEMOTION2, MKTAG('T', 'M', '2', '0') }, { CODEC_ID_CSCD, MKTAG('C', 'S', 'C', 'D') }, { CODEC_ID_ZMBV, MKTAG('Z', 'M', 'B', 'V') }, { CODEC_ID_KMVC, MKTAG('K', 'M', 'V', 'C') }, { CODEC_ID_CAVS, MKTAG('C', 'A', 'V', 'S') }, { CODEC_ID_JPEG2000, MKTAG('M', 'J', '2', 'C') }, { CODEC_ID_VMNC, MKTAG('V', 'M', 'n', 'c') }, { CODEC_ID_TARGA, MKTAG('t', 'g', 'a', ' ') }, { CODEC_ID_CLJR, MKTAG('c', 'l', 'j', 'r') }, { CODEC_ID_DIRAC, MKTAG('d', 'r', 'a', 'c') }, { CODEC_ID_NONE, 0 } }; const AVCodecTag codec_wav_tags[] = { { CODEC_ID_PCM_S16LE, 0x0001 }, { CODEC_ID_PCM_U8, 0x0001 }, /* must come after s16le in this list */ { CODEC_ID_PCM_S24LE, 0x0001 }, { CODEC_ID_PCM_S32LE, 0x0001 }, { CODEC_ID_ADPCM_MS, 0x0002 }, { CODEC_ID_PCM_F32LE, 0x0003 }, { CODEC_ID_PCM_F64LE, 0x0003 }, /* must come after f32le in this list */ { CODEC_ID_PCM_ALAW, 0x0006 }, { CODEC_ID_PCM_MULAW, 0x0007 }, { CODEC_ID_WMAVOICE, 0x000A }, { CODEC_ID_ADPCM_IMA_WAV, 0x0011 }, { CODEC_ID_PCM_ZORK, 0x0011 }, /* must come after adpcm_ima_wav in this list */ { CODEC_ID_ADPCM_YAMAHA, 0x0020 }, { CODEC_ID_TRUESPEECH, 0x0022 }, { CODEC_ID_GSM_MS, 0x0031 }, { CODEC_ID_ADPCM_G726, 0x0045 }, { CODEC_ID_MP2, 0x0050 }, { CODEC_ID_MP3, 0x0055 }, { CODEC_ID_ADPCM_IMA_DK4, 0x0061 }, /* rogue format number */ { CODEC_ID_ADPCM_IMA_DK3, 0x0062 }, /* rogue format number */ { CODEC_ID_VOXWARE, 0x0075 }, { CODEC_ID_AAC, 0x00ff }, { CODEC_ID_WMAV1, 0x0160 }, { CODEC_ID_WMAV2, 0x0161 }, { CODEC_ID_WMAPRO, 0x0162 }, { CODEC_ID_WMALOSSLESS, 0x0163 }, { CODEC_ID_ADPCM_CT, 0x0200 }, { CODEC_ID_ATRAC3, 0x0270 }, { CODEC_ID_IMC, 0x0401 }, { CODEC_ID_AC3, 0x2000 }, { CODEC_ID_DTS, 0x2001 }, { CODEC_ID_SONIC, 0x2048 }, { CODEC_ID_SONIC_LS, 0x2048 }, { CODEC_ID_AAC, 0x706d }, { CODEC_ID_FLAC, 0xF1AC }, { CODEC_ID_ADPCM_SWF, ('S'<<8)+'F' }, { CODEC_ID_VORBIS, ('V'<<8)+'o' }, //HACK/FIXME, does vorbis in WAV/AVI have an (in)official id? /* FIXME: All of the IDs below are not 16 bit and thus illegal. */ // for NuppelVideo (nuv.c) { CODEC_ID_PCM_S16LE, MKTAG('R', 'A', 'W', 'A') }, { CODEC_ID_MP3, MKTAG('L', 'A', 'M', 'E') }, { CODEC_ID_MP3, MKTAG('M', 'P', '3', ' ') }, { 0, 0 }, }; #ifdef CONFIG_MUXERS offset_t start_tag(ByteIOContext *pb, const char *tag) { put_tag(pb, tag); put_le32(pb, 0); return url_ftell(pb); } void end_tag(ByteIOContext *pb, offset_t start) { offset_t pos; pos = url_ftell(pb); url_fseek(pb, start - 4, SEEK_SET); put_le32(pb, (uint32_t)(pos - start)); url_fseek(pb, pos, SEEK_SET); } /* WAVEFORMATEX header */ /* returns the size or -1 on error */ int put_wav_header(ByteIOContext *pb, AVCodecContext *enc) { int bps, blkalign, bytespersec; int hdrsize = 18; if(!enc->codec_tag || enc->codec_tag > 0xffff) return -1; put_le16(pb, enc->codec_tag); put_le16(pb, enc->channels); put_le32(pb, enc->sample_rate); if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3 || enc->codec_id == CODEC_ID_GSM_MS) { bps = 0; } else if (enc->codec_id == CODEC_ID_ADPCM_IMA_WAV || enc->codec_id == CODEC_ID_ADPCM_MS || enc->codec_id == CODEC_ID_ADPCM_G726 || enc->codec_id == CODEC_ID_ADPCM_YAMAHA) { // bps = 4; } else { bps = av_get_bits_per_sample(enc->codec_id); } if(bps != enc->bits_per_sample && enc->bits_per_sample){ av_log(enc, AV_LOG_WARNING, "requested bits_per_sample (%d) and actually stored (%d) differ\n", enc->bits_per_sample, bps); } if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3 || enc->codec_id == CODEC_ID_AC3) { blkalign = enc->frame_size; //this is wrong, but it seems many demuxers do not work if this is set correctly //blkalign = 144 * enc->bit_rate/enc->sample_rate; } else if (enc->codec_id == CODEC_ID_ADPCM_G726) { // blkalign = 1; } else if (enc->block_align != 0) { /* specified by the codec */ blkalign = enc->block_align; } else blkalign = enc->channels*bps >> 3; if (enc->codec_id == CODEC_ID_PCM_U8 || enc->codec_id == CODEC_ID_PCM_S24LE || enc->codec_id == CODEC_ID_PCM_S32LE || enc->codec_id == CODEC_ID_PCM_F32LE || enc->codec_id == CODEC_ID_PCM_F64LE || enc->codec_id == CODEC_ID_PCM_S16LE) { bytespersec = enc->sample_rate * blkalign; } else { bytespersec = enc->bit_rate / 8; } put_le32(pb, bytespersec); /* bytes per second */ put_le16(pb, blkalign); /* block align */ put_le16(pb, bps); /* bits per sample */ if (enc->codec_id == CODEC_ID_MP3) { put_le16(pb, 12); /* wav_extra_size */ hdrsize += 12; put_le16(pb, 1); /* wID */ put_le32(pb, 2); /* fdwFlags */ put_le16(pb, 1152); /* nBlockSize */ put_le16(pb, 1); /* nFramesPerBlock */ put_le16(pb, 1393); /* nCodecDelay */ } else if (enc->codec_id == CODEC_ID_MP2) { put_le16(pb, 22); /* wav_extra_size */ hdrsize += 22; put_le16(pb, 2); /* fwHeadLayer */ put_le32(pb, enc->bit_rate); /* dwHeadBitrate */ put_le16(pb, enc->channels == 2 ? 1 : 8); /* fwHeadMode */ put_le16(pb, 0); /* fwHeadModeExt */ put_le16(pb, 1); /* wHeadEmphasis */ put_le16(pb, 16); /* fwHeadFlags */ put_le32(pb, 0); /* dwPTSLow */ put_le32(pb, 0); /* dwPTSHigh */ } else if (enc->codec_id == CODEC_ID_GSM_MS) { put_le16(pb, 2); /* wav_extra_size */ hdrsize += 2; put_le16(pb, enc->frame_size); /* wSamplesPerBlock */ } else if (enc->codec_id == CODEC_ID_ADPCM_IMA_WAV) { put_le16(pb, 2); /* wav_extra_size */ hdrsize += 2; put_le16(pb, enc->frame_size); /* wSamplesPerBlock */ } else if(enc->extradata_size){ put_le16(pb, enc->extradata_size); put_buffer(pb, enc->extradata, enc->extradata_size); hdrsize += enc->extradata_size; if(hdrsize&1){ hdrsize++; put_byte(pb, 0); } } else { hdrsize -= 2; } return hdrsize; } /* BITMAPINFOHEADER header */ void put_bmp_header(ByteIOContext *pb, AVCodecContext *enc, const AVCodecTag *tags, int for_asf) { put_le32(pb, 40 + enc->extradata_size); /* size */ put_le32(pb, enc->width); put_le32(pb, enc->height); put_le16(pb, 1); /* planes */ put_le16(pb, enc->bits_per_sample ? enc->bits_per_sample : 24); /* depth */ /* compression type */ put_le32(pb, enc->codec_tag); put_le32(pb, enc->width * enc->height * 3); put_le32(pb, 0); put_le32(pb, 0); put_le32(pb, 0); put_le32(pb, 0); put_buffer(pb, enc->extradata, enc->extradata_size); if (enc->extradata_size & 1) put_byte(pb, 0); } #endif //CONFIG_MUXERS #ifdef CONFIG_DEMUXERS /* We could be given one of the three possible structures here: * WAVEFORMAT, PCMWAVEFORMAT or WAVEFORMATEX. Each structure * is an expansion of the previous one with the fields added * at the bottom. PCMWAVEFORMAT adds 'WORD wBitsPerSample' and * WAVEFORMATEX adds 'WORD cbSize' and basically makes itself * an openended structure. */ void get_wav_header(ByteIOContext *pb, AVCodecContext *codec, int size) { int id; id = get_le16(pb); codec->codec_type = CODEC_TYPE_AUDIO; codec->codec_tag = id; codec->channels = get_le16(pb); codec->sample_rate = get_le32(pb); codec->bit_rate = get_le32(pb) * 8; codec->block_align = get_le16(pb); if (size == 14) { /* We're dealing with plain vanilla WAVEFORMAT */ codec->bits_per_sample = 8; }else codec->bits_per_sample = get_le16(pb); if (size >= 18) { /* We're obviously dealing with WAVEFORMATEX */ int cbSize = get_le16(pb); /* cbSize */ size -= 18; cbSize = FFMIN(size, cbSize); if (cbSize >= 22 && id == 0xfffe) { /* WAVEFORMATEXTENSIBLE */ codec->bits_per_sample = get_le16(pb); get_le32(pb); /* dwChannelMask */ id = get_le32(pb); /* 4 first bytes of GUID */ url_fskip(pb, 12); /* skip end of GUID */ cbSize -= 22; size -= 22; } codec->extradata_size = cbSize; if (cbSize > 0) { codec->extradata = av_mallocz(codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE); get_buffer(pb, codec->extradata, codec->extradata_size); size -= cbSize; } /* It is possible for the chunk to contain garbage at the end */ if (size > 0) url_fskip(pb, size); } codec->codec_id = wav_codec_get_id(id, codec->bits_per_sample); } int wav_codec_get_id(unsigned int tag, int bps) { int id; id = codec_get_id(codec_wav_tags, tag); if (id <= 0) return id; /* handle specific u8 codec */ if (id == CODEC_ID_PCM_S16LE && bps == 8) id = CODEC_ID_PCM_U8; if (id == CODEC_ID_PCM_S16LE && bps == 24) id = CODEC_ID_PCM_S24LE; if (id == CODEC_ID_PCM_S16LE && bps == 32) id = CODEC_ID_PCM_S32LE; if (id == CODEC_ID_PCM_F32LE && bps == 64) id = CODEC_ID_PCM_F64LE; if (id == CODEC_ID_ADPCM_IMA_WAV && bps == 8) id = CODEC_ID_PCM_ZORK; return id; } #endif // CONFIG_DEMUXERS void ff_parse_specific_params(AVCodecContext *stream, int *au_rate, int *au_ssize, int *au_scale) { int gcd; *au_ssize= stream->block_align; if(stream->frame_size && stream->sample_rate){ *au_scale=stream->frame_size; *au_rate= stream->sample_rate; }else if(stream->codec_type == CODEC_TYPE_VIDEO){ *au_scale= stream->time_base.num; *au_rate = stream->time_base.den; }else{ *au_scale= stream->block_align ? stream->block_align*8 : 8; *au_rate = stream->bit_rate ? stream->bit_rate : 8*stream->sample_rate; } gcd= ff_gcd(*au_scale, *au_rate); *au_scale /= gcd; *au_rate /= gcd; }