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• Why are v0, v1, and v2 of ffmpeg still under active development ? What happened to ppa:jon-severinsson/ffmpeg ?

  12 avril 2015, par cxrodgers

  I know about the long history of ffmpeg and libav. Personally, I preferred to use Jon Severinsson’s PPA, as suggested in many answers here on stackoverflow or askubuntu. However, recently this PPA seems to have gone down recently (this page, which is the link everyone always gives, is dead). I don’t see if he put up a newer version, although I admit I find launchpad hard to navigate. Did it get replaced with this one from Doug McMahon or this one from Sam Rog ?

  Ok, so maybe I need to download it myself. I visit the releases page for ffmpeg, and there seems to be simultaneous development of releases from v2 (2.6.2), v1 (1.2.12, from February), and v0 (0.10.16, from March of this year). 0.10 isn’t even the newest of the v0 series, and yet it seems to be the most recently updated of that series, and (coincidentally ?) also the version that I most recently got from the PPA. Admittedly this was on a slightly older distribution (Linux Mint 16).

  ffmpeg -version
  
  ffmpeg version 0.10.12-7:0.10.12-1~saucy1

  So, which version should I download, now that the PPA is gone ? Does it depend on the distribution I’m using ?

• AVCodecContext::channel_layout 0 for WAV files

  25 novembre 2020, par cmannett85

  I have been successfully loading compressed audio files using FFmpeg and querying their channel_layouts using some code I've written :

  



  AVFormatContext* fmtCxt = nullptr;
avformat_open_input( &fmtCxt, "###/440_sine.wav", nullptr, nullptr );
avformat_find_stream_info( fmtCxt, nullptr );
av_find_best_stream( fmtCxt, AVMEDIA_TYPE_AUDIO, -1, -1, nullptr, 0 );

AVCodecContext* codecCxt = fmtCxt->streams[ret]->codec;
AVCodec* codec = avcodec_find_decoder( codecCxt->codec_id );
avcodec_open2( codecCxt, codec, nullptr );

std::cout << "Channel Layout: " << codecCxt->channel_layout << std::endl;
av_dump_format( fmtCxt, 0, "###/440_sine.wav", 0 );


  



  I've removed all error checking for brevity. However for Microsoft WAV files (mono or stereo) the AVCodecContext::channel_layout member is always 0 - despite ffprobe and av_dump_format(..) both returning valid information :

  



  Input #0, wav, from '###/440_sine.wav':
Duration: 00:00:00.01, bitrate: 740 kb/s
Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 1 channels, s16, 705 kb/s


  



  Also codecCxt->channels returns the correct value. Using a flac file (with exactly the same audio data generated from the same application), gives a channel_layout of 0x4 (AV_CH_FRONT_CENTER).

  


• AVCodecContext::channel_layout 0 for WAV files

  30 décembre 2013, par cmannett85

  I have been successfully loading compressed audio files using FFmpeg and querying their channel_layouts using some code I've written :

  AVFormatContext* fmtCxt = nullptr;
  
  avformat_open_input( &fmtCxt, "###/440_sine.wav", nullptr, nullptr );
  
  avformat_find_stream_info( fmtCxt, nullptr );
  
  av_find_best_stream( fmtCxt, AVMEDIA_TYPE_AUDIO, -1, -1, nullptr, 0 );
  
  
  
  AVCodecContext* codecCxt = fmtCxt->streams[ret]->codec;
  
  AVCodec* codec = avcodec_find_decoder( codecCxt->codec_id );
  
  avcodec_open2( codecCxt, codec, nullptr );
  
  
  
  std::cout << "Channel Layout: " << codecCxt->channel_layout << std::endl;
  
  av_dump_format( fmtCxt, 0, "###/440_sine.wav", 0 );

  I've removed all error checking for brevity. However for Microsoft WAV files (mono or stereo) the AVCodecContext::channel_layout member is always 0 - despite ffprobe and av_dump_format(..) both returning valid information :

  Input #0, wav, from '###/440_sine.wav':
  
  Duration: 00:00:00.01, bitrate: 740 kb/s
  
  Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 1 channels, s16, 705 kb/s

  Also codecCxt->channels returns the correct value. Using a flac file (with exactly the same audio data generated from the same application), gives a channel_layout of 0x4 (AV_CH_FRONT_CENTER).