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• movenc : Add a flag for indicating a discontinuous fragment

  20 novembre 2014, par Martin Storsjö

  movenc : Add a flag for indicating a discontinuous fragment
  This allows creating a later mp4 fragment without sequentially
  
  writing the earlier ones before (when called from a segmenter).
  Normally when writing a fragmented mp4 file sequentially, the
  
  first timestamps of a fragment are adjusted to match the
  
  end of the previous fragment, to make sure the timestamp is the
  
  same, even if it is calculated as the sum of previous fragment
  
  durations. (And for the first packet in a file, the offset of
  
  the first packet is written using an edit list.)
  When writing an individual mp4 fragment discontinuously like this
  
  (with potentially writing the earlier fragments separately later),
  
  there’s a risk of getting a gap in the timeline if the duration
  
  field of the last packet in the previous fragment doesn’t match up
  
  with the start time of the next fragment.
  Using this requires setting -avoid_negative_ts make_non_negative
  
  (or -avoid_negative_ts 0).
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/movenc.c
  • [DBH] libavformat/movenc.h

• movenc : Allow writing a DASH sidx atom at the start of files

  21 octobre 2014, par Martin Storsjö

  movenc : Allow writing a DASH sidx atom at the start of files
  This is mapped to the faststart flag (which in this case
  
  perhaps should be called "shift and write index at the
  
  start of the file"), which for fragmented files will
  
  write a sidx index at the start.
  When segmenting DASH into files, there’s usually one sidx
  
  at the start of each segment (although it’s not clear to me
  
  whether that actually is necessary). When storing all of it
  
  in one file, the MPD doesn’t necessarily need to describe
  
  the individual segments, but the offsets of the fragments can be
  
  fetched from one large sidx atom at the start of the file. This
  
  allows creating files for the DASH ISO BMFF on-demand profile.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/movenc.c
  • [DBH] libavformat/movenc.h

• 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.