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• Ignore streams when finding stream info

  17 mars 2018, par CSNewman

  I’m trying to speed up the start of ffmpeg when processing my live stream, and have narrowed down the issue to the ‘avformat_find_stream_info’ function. The source I’m trying to process seems to have a number of streams that ffmpeg is unable to determine what they are and therefore spends a while trying to find information about them (The entire analyse window). I know ahead of time that I only want to find information about stream #0:0 and #0:1, and I will be disregarding the other streams anyways.

  I managed to work around this using the API by setting the number of streams before the find information call and then restoring the value afterwards.

  inputContext->nb_streams = (uint) 2;
  
  if (ffmpeg.avformat_find_stream_info(inputContext, null) < 0)
  
  {
  
      throw new InvalidOperationException("Could not read stream information.");
  
  }
  
  inputContext->nb_streams = oldSize;

  However, I would prefer to use the CLI interface of ffmpeg.

  My current command

  ffmpeg -find_stream_info false -i http://192.168.1.112:5004/auto/v1 -c copy -map 0:v:0 -map 0:a:0 -ignore_unknown   -f hls -hls_flags delete_segments  -segment_list playlist.m3u8 -segment_list_type hls -segment_list_size 10 -segment_list_flags +live -segment_time 10 -f segment stream%%05d.ts

  Giving the following input (Unneeded logging removed)

  [mpeg2video @ 000001ce79423440] Invalid frame dimensions 0x0.
  
      Last message repeated 9 times
  
  [mpegts @ 000001ce7941b740] Could not find codec parameters for stream 5 (Unknown: none ([11][0][0][0] / 0x000B)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [mpegts @ 000001ce7941b740] Could not find codec parameters for stream 6 (Unknown: none ([11][0][0][0] / 0x000B)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [mpegts @ 000001ce7941b740] Could not find codec parameters for stream 7 
  
  (Unknown: none ([5][0][0][0] / 0x0005)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [mpegts @ 000001ce7941b740] Could not find codec parameters for stream 8 
  
  (Unknown: none ([5][0][0][0] / 0x0005)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  Input #0, mpegts, from 'http://192.168.1.112:5004/auto/v1':
  
    Duration: N/A, start: 91296.182311, bitrate: N/A
  
    Program 4165
  
      Stream #0:0[0x65]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, top first), 704x576 [SAR 16:11 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
  
      Stream #0:1[0x66](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 256 kb/s
  
      Stream #0:2[0x6a](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, mono, s16p, 64 kb/s (visual impaired) (dependent)
  
      Stream #0:3[0x69](eng): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)
  
      Stream #0:4[0x98]: Audio: mp2 ([6][0][0][0] / 0x0006), 48000 Hz, stereo, s16p, 128 kb/s
  
      Stream #0:5[0x1c21]: Unknown: none ([11][0][0][0] / 0x000B)
  
      Stream #0:6[0x1c33]: Unknown: none ([11][0][0][0] / 0x000B)
  
      Stream #0:7[0x1bbf]: Unknown: none ([5][0][0][0] / 0x0005)
  
      Stream #0:8[0x1bc1]: Unknown: none ([5][0][0][0] / 0x0005)

  I’m unsure if there’s a way to achieve the same functionality with the CLI, however I’m open changing how my setup works.

  One idea that I considered was running two ffmpeg instances, one to strip the unneeded streams (and not find the stream info) and then have another that takes that stripped stream and performs the rest of the functionality.

  Any insight here would be grateful, thanks in advance.

• avutil/stereo3d : Fill out stereo info provided by Vision Pro files

  30 mai 2024, par Derek Buitenhuis

  avutil/stereo3d : Fill out stereo info provided by Vision Pro files
  Based on what is in the files themselves, and what the API provides
  
  to users.
  URLs :
  
    * https://developer.apple.com/documentation/videotoolbox/kvtcompressionpropertykey_heroeye
  
    * https://developer.apple.com/documentation/videotoolbox/kvtcompressionpropertykey_stereocamerabaseline
  
    * https://developer.apple.com/documentation/videotoolbox/kvtcompressionpropertykey_horizontaldisparityadjustment
  
    * https://developer.apple.com/documentation/coremedia/kcmformatdescriptionextension_horizontalfieldofview
  Signed-off-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  

  • [DH] doc/APIchanges
  • [DH] libavutil/stereo3d.c
  • [DH] libavutil/stereo3d.h
  • [DH] libavutil/version.h

• How to get info on a partial incoming mov file in javascript ? [closed]

  30 août 2020, par David542

  I'm not sure if this is more a JavaScript question or ffmpeg, but suppose I have a scenario where a user is uploading a 100GB file. And, before they upload it (or actually, as soon as we detect the first few frames or whatever), we want to make sure that it is a "valid" file — let's say for this question we want to verify that it is :

  


  

  • 29.97 fps

  


  • Video bitrate > X

  


  • Codec of com.apple.finalcutstudio.prores

  


  


  What would be the best way to do this ? I was thinking something like :

  


  

  1. A user clicks the upload button and selects their file.

  


  2. We upload the first 1MB of that file to our server — check that using ffmpeg (how to ignore errors or something with ffmpeg ?)

  


  3. If the file passes our initial checks we upload the entire video file. If not, we raise a warning to the end user and stop the upload.

  


  


  How could this process be done ? I am seeking a JavaScript snippet (JS Fiddle ?) and a backend snippet (to receive the partial input and issue the ffmpeg commands).