I have this command: ffmpeg -i "rtmp://url live=1" -map 0:1 -af aresample=16000,asetnsamples=16000 -f segment -segment_time 5 -segment_format sw out%04d.sw
strips the audio from a live stream and creates 160kb files. However, when I try the same command on a file, as opposed to a live stream, I get chunks of variable file sizes. The file sizes and number of samples in the file (160,000 bytes, 80,000 samples) are very important to the API I'm using. What changes do I have to make to my command so that it can handle both rtmp streams and other types of video? Here is the command and the output when it produces an undesirable file size: ffmpeg -i file1.mp4 -map 0:1 -af aresample=16000,asetnsamples=16000 -f segment -segment_time 5 -segment_format sw out%04d.sw ffmpeg version 2.8.4 Copyright (c) 2000-2015 the FFmpeg developers built with gcc 5.2.0 (GCC) configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib libavutil 54. 31.100 / 54. 31.100 libavcodec 56. 60.100 / 56. 60.100 libavformat 56. 40.101 / 56. 40.101 libavdevice 56. 4.100 / 56. 4.100 libavfilter 5. 40.101 / 5. 40.101 libswscale 3. 1.101 / 3. 1.101 libswresample 1. 2.101 / 1. 2.101 libpostproc 53. 3.100 / 53. 3.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'file1.mp4': Metadata: major_brand : mp42 minor_version : 0 compatible_brands: isommp42 creation_time : 2015-04-03 05:49:11 Duration: 00:28:48.80, start: 0.000000, bitrate: 358 kb/s Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 260 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default) Metadata: creation_time : 1970-01-01 00:00:00 handler_name : VideoHandler Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 95 kb/s (default) Metadata: creation_time : 2015-04-03 05:49:18 handler_name : IsoMedia File Produced by Google, 5-11-2011 Output #0, segment, to 'out%04d.sw': Metadata: major_brand : mp42 minor_version : 0 compatible_brands: isommp42 encoder : Lavf56.40.101 Stream #0:0(und): Audio: pcm_s16le, 16000 Hz, stereo, s16, 512 kb/s (default) Metadata: creation_time : 2015-04-03 05:49:18 handler_name : IsoMedia File Produced by Google, 5-11-2011 encoder : Lavc56.60.100 pcm_s16le Stream mapping: Stream #0:1 -> #0:0 (aac (native) -> pcm_s16le (native)) Press [q] to stop, [?] for help size=N/A time=00:28:49.00 bitrate=N/A video:0kB audio:108062kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown For reference, here is the output when an rtmp stream is used as an input: ffmpeg -i "rtmp://url live=1" -map 0:1 -af aresample=16000,asetnsamples=16000 -f segment -segment_time 5 -segment_format sw out%04d.sw ffmpeg version 2.8.4 Copyright (c) 2000-2015 the FFmpeg developers built with gcc 5.2.0 (GCC) configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib libavutil 54. 31.100 / 54. 31.100 libavcodec 56. 60.100 / 56. 60.100 libavformat 56. 40.101 / 56. 40.101 libavdevice 56. 4.100 / 56. 4.100 libavfilter 5. 40.101 / 5. 40.101 libswscale 3. 1.101 / 3. 1.101 libswresample 1. 2.101 / 1. 2.101 libpostproc 53. 3.100 / 53. 3.100 Metadata: author dsf presetname Custom creationdate Wed Mar 16 09:40:36 2016 videodevice BisonCam, NB Pro framerate 29.97 width 640.00 height 480.00 videocodecid avc1 videodatarate 1000.00 avclevel 31.00 avcprofile 66.00 videokeyframe_frequency4.00 audiodevice Microphone (Realtek High Definition Audio) audiosamplerate 22050.00 audiochannels 1.00 audioinputvolume 75.00 audiocodecid .mp3 audiodatarate 48.00 Input #0, flv, from 'rtmp:/url live=1': Metadata: author : dsf copyright : description : keywords : rating : title : presetname : Custom creationdate : Wed Mar 16 09:40:36 2016 : videodevice : BisonCam, NB Pro avclevel : 31 avcprofile : 66 videokeyframe_frequency: 4 audiodevice : Microphone (Realtek High Definition Audio) audiochannels : 1 audioinputvolume: 75 Duration: N/A, start: 0.019000, bitrate: 1073 kb/s Stream #0:0: Video: h264 (Baseline), yuv420p(tv), 640x480 [SAR 1:1 DAR 4:3], 1024 kb/s, 30.30 fps, 30 tbr, 1k tbn, 60 tbc Stream #0:1: Audio: mp3, 22050 Hz, mono, s16p, 49 kb/s Output #0, segment, to 'out%04d.sw': Metadata: author : dsf copyright : description : keywords : rating : title : presetname : Custom creationdate : Wed Mar 16 09:40:36 2016 : videodevice : BisonCam, NB Pro avclevel : 31 avcprofile : 66 videokeyframe_frequency: 4 audiodevice : Microphone (Realtek High Definition Audio) audiochannels : 1 audioinputvolume: 75 encoder : Lavf56.40.101 Stream #0:0: Audio: pcm_s16le, 16000 Hz, mono, s16, 256 kb/s Metadata: encoder : Lavc56.60.100 pcm_s16le Stream mapping: Stream #0:1 -> #0:0 (mp3 (native) -> pcm_s16le (native)) Press [q] to stop, [?] for help size=N/A time=00:00:14.00 bitrate=N/A video:0kB audio:438kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user