输入：html
flv格式，视频264编码，音频speex编码ios
-8:[root@andrew ffmpeg-3.0./ffprobe test_speex1.flv 32:ffprobe version 3.0-static32: Copyright (c) 2007-2016 the FFmpeg developers32: 32: built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-16) 32: configuration: --enable-gpl --enable-nonfree --disable-shared --enable-postproc --enable-bzlib --enable-zlib --enable-parsers --enable-libx264 --enable-libmp3lame --enable-libfaac --enable-libfdk-aac --enable-pthreads --extra-ldflags=-static --disable-ffserver --enable-ffplay --enable-asm --enable-yasm --enable-optimizations --pkg-config-flags=--static --extra-cflags=--static --extra-version=static --extra-ldflags=-L/usr/local/lib --extra-cflags=-I/usr/local/include --extra-libs=-lrtmp --enable-libspeex --enable-encoder=libspeex --enable-decoder=libspeex 32: libavutil 55. 17.103 / 55. 17.103 32: libavcodec 57. 24.102 / 57. 24.102 32: libavformat 57. 25.100 / 57. 25.100 32: libavdevice 57. 0.101 / 57. 0.101 32: libavfilter 6. 31.100 / 6. 31.100 32: libswscale 4. 0.100 / 4. 0.100 32: libswresample 2. 0.101 / 2. 0.101 32: libpostproc 54. 0.100 / 54. 0.100 32:[h264 @ 0x242c260] decoding video ....... 32:Input #0, flv, from 'test_speex1.flv': 32: Metadata: 32: metadatacreator : 32:Yet Another Metadata Injector for FLV - Version 1.832: 32: canSeekToEnd : 32:true32: 32: videosize : 32:2034203232: 32: audiosize : 32:272241432: 32: lastkeyframetimestamp: 32:31832: 32: lastkeyframelocation: 32:2313943332: 32: encoder : 32:Lavf57.25.10032: 32: Duration: 32:00:00:01.7332:, start: 32:0.08100032:, bitrate: 32:331 kb/s32: 32: Stream #0:032:: Video: h264 (High), yuv420p, 608x448 [SAR 56:57 DAR 4:3]32:, 32:15.17 fps, 32:15 tbr, 32:1k tbn, 32:30 tbc32: 32: Stream #0:132:: Audio: speex, 16000 Hz, mono, s16, 27 kb/s32:
输出h264+mp3app
例1：ide
./ffmpeg -re -i test_speex1.flv -vcodec libx264 -acodec libmp3lame -y -f flv test_1out.flvpost
-8:[root@andrew ffmpeg-3.0]# ./ffmpeg -re -i test_speex1.flv -vcodec libx264 -acodec libmp3lame -y -f flv test_1out.flv 32:ffmpeg version 3.0-static32: Copyright (c) 2000-2016 the FFmpeg developers32: 32: built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-16) 32: configuration: --enable-gpl --enable-nonfree --disable-shared --enable-postproc --enable-bzlib --enable-zlib --enable-parsers --enable-libx264 --enable-libmp3lame --enable-libfaac --enable-libfdk-aac --enable-pthreads --extra-ldflags=-static --disable-ffserver --enable-ffplay --enable-asm --enable-yasm --enable-optimizations --pkg-config-flags=--static --extra-cflags=--static --extra-version=static --extra-ldflags=-L/usr/local/lib --extra-cflags=-I/usr/local/include --extra-libs=-lrtmp --enable-libspeex --enable-encoder=libspeex --enable-decoder=libspeex 32: libavutil 55. 17.103 / 55. 17.103 32: libavcodec 57. 24.102 / 57. 24.102 32: libavformat 57. 25.100 / 57. 25.100 32: libavdevice 57. 0.101 / 57. 0.101 32: libavfilter 6. 31.100 / 6. 31.100 32: libswscale 4. 0.100 / 4. 0.100 32: libswresample 2. 0.101 / 2. 0.101 32: libpostproc 54. 0.100 / 54. 0.100 32:[h264 @ 0x3ec1b40] decoding video ....... 32:Input #0, flv, from 'test_speex1.flv': 32: Metadata: 32: metadatacreator : 32:Yet Another Metadata Injector for FLV - Version 1.832: 32: canSeekToEnd : 32:true32: 32: videosize : 32:2034203232: 32: audiosize : 32:272241432: 32: lastkeyframetimestamp: 32:31832: 32: lastkeyframelocation: 32:2313943332: 32: encoder : 32:Lavf57.25.10032: 32: Duration: 32:00:00:01.7332:, start: 32:0.08100032:, bitrate: 32:331 kb/s32: 32: Stream #0:032:: Video: h264 (High), yuv420p, 608x448 [SAR 56:57 DAR 4:3]32:, 32:15.17 fps, 32:15 tbr, 32:1k tbn, 32:30 tbc32: 32: Stream #0:132:: Audio: speex, 16000 Hz, mono, s16, 27 kb/s32: 32:[libx264 @ 0x3ec2fe0] x264 init info........ 32:[libx264 @ 0x3ec2fe0] using SAR=56/57 32:[libx264 @ 0x3ec2fe0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2 32:[libx264 @ 0x3ec2fe0] profile High, level 2.2 32:[libx264 @ 0x3ec2fe0] 264 - core 144 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=1 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=15 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00 16:[flv @ 0x3f6f440] FLV does not support sample rate 16000, choose from (44100, 22050, 11025) 16:[flv @ 0x3f6f440] Audio codec mp3 not compatible with flv 32:Output #0, flv, to 'test_1out.flv': 32: Metadata: 32: metadatacreator : 32:Yet Another Metadata Injector for FLV - Version 1.832: 32: canSeekToEnd : 32:true32: 32: videosize : 32:2034203232: 32: audiosize : 32:272241432: 32: lastkeyframetimestamp: 32:31832: 32: lastkeyframelocation: 32:2313943332: 32: encoder : 32:Lavf57.25.10032: 32: Stream #0:032:: Video: h264 (libx264) ([7][0][0][0] / 0x0007), yuv420p, 608x448 [SAR 56:57 DAR 4:3], q=-1--132:, 32:15 fps, 32:1k tbn, 32:15 tbc32: 32: Metadata: 32: encoder : 32:Lavc57.24.102 libx26432: 32: Side data: 32: 24:unknown side data type 10 (24 bytes)32: 32: Stream #0:132:: Audio: mp3 (libmp3lame) ([2][0][0][0] / 0x0002), 16000 Hz, mono, s16p32: 32: Metadata: 32: encoder : 32:Lavc57.24.102 libmp3lame32: 32:Stream mapping: 32: Stream #0:0 -> #0:032: (h264 (native) -> h264 (libx264))32: 32: Stream #0:1 -> #0:132: (speex (libspeex) -> mp3 (libmp3lame))32: 16:Could not write header for output file #0 (incorrect codec parameters ?): Function not implemented
问题：ui
16:[flv @ 0x3f6f440] FLV does not support sample rate 16000, choose from (44100, 22050, 11025)
16:[flv @ 0x3f6f440] Audio codec mp3 not compatible with flv编码
libmp3lame.c代码code
static const int libmp3lame_sample_rates[] = {
44100, 48000, 32000, 22050, 24000, 16000, 11025, 12000, 8000, 0
};
例2：orm
./ffmpeg -re -i test_speex1.flv -vcodec libx264 -acodec libmp3lame -ar 22050 -y -f flv test_1out.flv视频
可以正常转码。
例3：
./ffmpeg -re -i test_speex1.flv -vcodec libx264 -acodec aac -y -f flv test_1out.flv
可以正常转码。即aac支持16kHz的采样率。
aacenctab.h
/* duplicated from avpriv_mpeg4audio_sample_rates to avoid shared build
* failures */
static const int mpeg4audio_sample_rates[16] = {
96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000, 7350
};
flvenc.c对采样率和声道的判断
static int get_audio_flags(AVFormatContext *s, AVCodecContext *enc)
{
int flags = (enc->bits_per_coded_sample == 16) ? FLV_SAMPLESSIZE_16BIT
: FLV_SAMPLESSIZE_8BIT;
if (enc->codec_id == AV_CODEC_ID_AAC) // specs force these parameters
return FLV_CODECID_AAC | FLV_SAMPLERATE_44100HZ |
FLV_SAMPLESSIZE_16BIT | FLV_STEREO;
else if (enc->codec_id == AV_CODEC_ID_SPEEX) {
if (enc->sample_rate != 16000) {
av_log(s, AV_LOG_ERROR,
"FLV only supports wideband (16kHz) Speex audio\n");
return AVERROR(EINVAL);
}
if (enc->channels != 1) {
av_log(s, AV_LOG_ERROR, "FLV only supports mono Speex audio\n");
return AVERROR(EINVAL);
}
return FLV_CODECID_SPEEX | FLV_SAMPLERATE_11025HZ | FLV_SAMPLESSIZE_16BIT;
} else {
switch (enc->sample_rate) {
case 44100:
flags |= FLV_SAMPLERATE_44100HZ;
break;
case 22050:
flags |= FLV_SAMPLERATE_22050HZ;
break;
case 11025:
flags |= FLV_SAMPLERATE_11025HZ;
break;
case 16000: // nellymoser only
case 8000: // nellymoser only
case 5512: // not MP3
if (enc->codec_id != AV_CODEC_ID_MP3) {
flags |= FLV_SAMPLERATE_SPECIAL;
break;
}
default:
av_log(s, AV_LOG_ERROR,
"FLV does not support sample rate %d, "
"choose from (44100, 22050, 11025)\n", enc->sample_rate);
return AVERROR(EINVAL);
}
}
if (enc->channels > 1)
flags |= FLV_STEREO;
switch (enc->codec_id) {
case AV_CODEC_ID_MP3:
flags |= FLV_CODECID_MP3 | FLV_SAMPLESSIZE_16BIT;
break;
case AV_CODEC_ID_PCM_U8:
flags |= FLV_CODECID_PCM | FLV_SAMPLESSIZE_8BIT;
break;
case AV_CODEC_ID_PCM_S16BE:
flags |= FLV_CODECID_PCM | FLV_SAMPLESSIZE_16BIT;
break;
case AV_CODEC_ID_PCM_S16LE:
flags |= FLV_CODECID_PCM_LE | FLV_SAMPLESSIZE_16BIT;
break;
case AV_CODEC_ID_ADPCM_SWF:
flags |= FLV_CODECID_ADPCM | FLV_SAMPLESSIZE_16BIT;
break;
case AV_CODEC_ID_NELLYMOSER:
if (enc->sample_rate == 8000)
flags |= FLV_CODECID_NELLYMOSER_8KHZ_MONO | FLV_SAMPLESSIZE_16BIT;
else if (enc->sample_rate == 16000)
flags |= FLV_CODECID_NELLYMOSER_16KHZ_MONO | FLV_SAMPLESSIZE_16BIT;
else
flags |= FLV_CODECID_NELLYMOSER | FLV_SAMPLESSIZE_16BIT;
break;
case AV_CODEC_ID_PCM_MULAW:
flags = FLV_CODECID_PCM_MULAW | FLV_SAMPLERATE_SPECIAL | FLV_SAMPLESSIZE_16BIT;
break;
case AV_CODEC_ID_PCM_ALAW:
flags = FLV_CODECID_PCM_ALAW | FLV_SAMPLERATE_SPECIAL | FLV_SAMPLESSIZE_16BIT;
break;
case 0:
flags |= enc->codec_tag << 4;
break;
default:
av_log(s, AV_LOG_ERROR, "Audio codec '%s' not compatible with FLV\n",
avcodec_get_name(enc->codec_id));
return AVERROR(EINVAL);
}
return flags;
}
从以上代码能够总结出如下几点：
1. 编码类型为AV_CODEC_ID_AAC，flv都支持
2.编码类型为AV_CODEC_ID_SPEEX，采样率只能为16000，而且单声道
3. 采用率为44100,22050,11025的全部编码方式都是支持的
4. MP3的编码方式不支持采样率为16000,8000和5512
总结：
使用ffmpeg转码speex到mp3时，须要指定输出的采样率，不然可能转码合成flv时出问题。