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• ffmpeg Extract multiple streams from mkv to mp4

  28 mai 2016, par Sebastien Lemichez

  The situation

  I’m working on a everything to high compatibility mp4 app.
  The goal is to pass a video file and get a mp4 file that can be played by almost every player.

  I’m using ffmpeg to do so with this command :

  "ffmpeg -i " + inputPath + " -c:v libx264 -profile:v baseline -level 3.0 -preset ultrafast " + outputPath

  I’m doing it in a c# wrapper and it’s working like a charm.

  The Problem

  The real problem comes with extra streams that you can commonly find in mkv files like extra audio stream and multiple subtitles.

  So my goal is to use ffprobe.exe to get all input streams, extract them into different files and then using mp4box.exe to add them to my high compatibility mp4 file generated by ffmpeg.exe

  What I’ve done so far

  I have managed to get input streams in json with a structure like this :

  "streams":[
  
      {
  
          "index": 0,
  
          "codec_name": "h264",
  
          "codec_type": "video"
  
      },
  
      {
  
          "index": 1,
  
          "codec_name": "aac",
  
          "codec_type": "audio"
  
      },
  
      {
  
          "index": 2,
  
          "codec_name": "subrip",
  
          "codec_type": "subtitle"
  
          "tags":{
  
              "language": "eng"
  
          }
  
      },
  
      {
  
          "index": 3,
  
          "codec_name": "subrip",
  
          "codec_type": "subtitle"
  
          "tags":{
  
              "language": "fre"
  
          }
  
      },
  
      {
  
          "index": 4,
  
          "codec_name": "aac",
  
          "codec_type": "audio"
  
          "tags":{
  
              "language": "fre"
  
              "title": "Commentary"
  
          }
  
      }
  
  ]

  Where I’m stuck

  To extract those extra stream I would need to do something like this :

  ffmpeg -i input.mkv \
  
  -map 0:2 -c copy subtitle-2.srt \
  
  -map 0:3 -c copy subtitle-3.srt \
  
  -map 0:4 -c copy audio-4.aac

  So is there a way to use my ffprobe result to get these file extension because I have a codec_name "subrip" that should be saved in a srt.

  I’m avoiding an hard coded list because if I miss a format it will break. I’m more looking for a ffmpeg or ffprobe associated list I can use.

  English is not my native language so sorry for any misstakes.

• FFmpeg. avcodec_find_encoder(AV_CODEC_ID_H264) return false

  14 juillet 2016, par Иван Чванов

  The problem : I can not connect the h264 codec for encoding and decoding of frames.

  ---

  Description :

  I downloaded from here ffmpeg library https://ffmpeg.zeranoe.com/builds/, version dev.

  Connect it to your project QT :

  extern "C"
  
  {
  
      #include 
  
      #include 
  
      #include 
  
      #include 
  
      #include 
  
  }
  
      
  
  #pragma comment (lib, "avcodec.lib")
  
  #pragma comment (lib, "avformat.lib")
  
  #pragma comment (lib, "swscale.lib")
  
  #pragma comment (lib, "avutil.lib")

  Next prescribe av_register_all(); to include all codecs.

  Next, call the function : avcodec_find_encoder(AV_CODEC_ID_H264), returns false.

  In the ReadMe file, the library said that it was collected with —enable-libx264 and —enable-gpl compile the keys including h264 codec that is supposed to be.

  If the call : avcodec_find_encoder(AV_CODEC_ID_MPEG1VIDEO), it returns an object AVCodec, as it should.

  I use the MinGW compiler. OC Windows 7.

  How can I resolve or work around the problem ? Compile the library itself has not yet obtained. I understand you to connect sources and "poking" them, that too is meaningless.

  ---

  ** Once again, I will describe my problem : **

  I need to encode the codec h264 (can VP9) individual frames in one program, and then decode them in another program. You can use other libraries. The language C ++. It is necessary to use interframe compression codec, rather than simply pressed apart frames.

  Sorry for my english.

  Ideas. Advice. Suggestions.

• FFmpeg. avcodec_find_encoder(AV_CODEC_ID_H264) return false

  14 juillet 2016, par Иван Чванов

  The problem : I can not connect the h264 codec for encoding and decoding of frames.

  ---

  Description :

  I downloaded from here ffmpeg library https://ffmpeg.zeranoe.com/builds/, version dev.

  Connect it to your project QT :

  extern "C"
  
  {
  
      #include 
  
      #include 
  
      #include 
  
      #include 
  
      #include 
  
  }
  
      
  
  #pragma comment (lib, "avcodec.lib")
  
  #pragma comment (lib, "avformat.lib")
  
  #pragma comment (lib, "swscale.lib")
  
  #pragma comment (lib, "avutil.lib")

  Next prescribe av_register_all(); to include all codecs.

  Next, call the function : avcodec_find_encoder(AV_CODEC_ID_H264), returns false.

  In the ReadMe file, the library said that it was collected with —enable-libx264 and —enable-gpl compile the keys including h264 codec that is supposed to be.

  If the call : avcodec_find_encoder(AV_CODEC_ID_MPEG1VIDEO), it returns an object AVCodec, as it should.

  I use the MinGW compiler. OC Windows 7.

  How can I resolve or work around the problem ? Compile the library itself has not yet obtained. I understand you to connect sources and "poking" them, that too is meaningless.

  ---

  ** Once again, I will describe my problem : **

  I need to encode the codec h264 (can VP9) individual frames in one program, and then decode them in another program. You can use other libraries. The language C ++. It is necessary to use interframe compression codec, rather than simply pressed apart frames.

  Sorry for my english.

  Ideas. Advice. Suggestions.