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• avformat/ttaenc : Defer freeing dynamic buffer

  20 mai 2020, par Andreas Rheinhardt

  avformat/ttaenc : Defer freeing dynamic buffer
  The TTA muxer writes a seektable in a dynamic buffer as it receives
  
  packets and when writing the trailer, closes the dynamic buffer using
  
  avio_close_dyn_buf(), writes the seektable and frees the buffer. But
  
  the TTA muxer already has a deinit function which unconditionally
  
  calls ffio_free_dyn_buf() on the dynamic buffer, so switching to
  
  avio_get_dyn_buf() means that one can remove the code to free the
  
  buffer ; furthermore, it also might save an allocation if the seektable
  
  is so small that it fits into the dynamic buffer's write buffer or if
  
  adding the padding that avio_close_dyn_buf() adds necessitated
  
  reallocating of the underlying buffer.
  Reviewed-by : James Almer <jamrial@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/ttaenc.c

• Can ffprobe consume piped ffmpeg output ?

  19 mai 2020, par slifty

  The Situation

  



  I'm writing a NodeJS script that takes a video stream (or file), pipes it to ffmpeg to standardize the format, and then sends it to various ETL processes to extract data from the video.

  



  I want my node-level data stream to have awareness of how far into the video it is, and it seems the best (only ?) way to do this is to use ffprobe to extract times from the stream packets.

  



  The Problem

  



  Before I actually start spawning ffmpeg commands, I'm trying to test at the CLI level. When I pipe ffmpeg's output directly to ffprobe, I receive a complaint :

  



  av_interleaved_write_frame(): Broken pipe
Error writing trailer of pipe:: Broken pipe


  



  The command in question :

  



  ffmpeg -i /path/to/in.mp4 -f mpegts - | ffprobe -i - -print_format json


  



  The Question

  



  Am I misunderstanding something about what ffprobe accepts ? I haven't found a single example of ffmpeg piping to ffprobe, which makes me nervous.

  



  Is it possible to pipe ffmpeg data directly to ffprobe ?

  



  Bonus points : if you have a better way of extracting timing information from the ffmpeg stream, take a look at this question

  


• avformat/matroskaenc : Allow a custom destination for writing Tags

  29 avril 2020, par Andreas Rheinhardt

  avformat/matroskaenc : Allow a custom destination for writing Tags
  Up until now, the Matroska muxer writes only one Tags level 1 element
  
  and therefore using a certain place to store the dynamic buffer used for
  
  writing it was hardcoded ; yet the Matroska specifications allow an
  
  unlimited amount of Tags elements and we have reason to write a second
  
  one : If chapters are provided after writing the header, they are written
  
  when writing the trailer ; yet the corresponding tags are ignored. This
  
  can be fixed by writing them in a second Tags element.
  Also use a MatroskaMuxContext * instead of an AVFormatContext * as
  
  parameter in mkv_write_tag() and mkv_write_tag_targets() as that is all
  
  these functions use.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskaenc.c