Recherche avancée

Sur d’autres sites (6909)

• How to update MP4 with the video length

  9 décembre 2015, par oygle

  I used youtube-dl to obtain a friends video. When I play it in VLC, I notice there is no time/length shown. As we need to cut part of this video with ffmpeg, can I use ffmpeg (or similar tool) to determine the length of the video, and then update the MP4 to contain the time/length ?

• avcodec/prores_aw : change src pix_fmt and alpha description

  8 novembre 2018, par Martin Vignali

  avcodec/prores_aw : change src pix_fmt and alpha description
  use b64a as src pix fmt (doesn't seems to have an impact on decoding)
  
  but it's the value use by official encoder
  

  • [DH] libavcodec/proresenc_anatoliy.c

• Tools/Techniques for investigating video corruption — ffmpeg / libavcodec

  17 juillet 2013, par Gopherkhan

  In my current work I'm trying to encode some images to h264 video using the FFMPEG's C library. The resulting video plays fine in VLC, but has no preview image. The video can play in VLC and Mplayer on ubuntu, but won't play on Mac or PC (in fact, it causes a "VTDecoderXPCService quit unexpectedly" error on Mac).

  If I run the resulting file through FFMPEG using the command line, the resulting file has a preview image, and plays correctly everywhere.

  Apparently the file that I get out of the program is corrupt in some weird place, but I don't have any output during my compilation or run to indicate where. I can't share my code at the moment (work code isn't open source yet :-( ), but I have tried a number of things :

  1. Writing only header and trailer data (av_write_trailer) and no frames
  2. writing frames only minus the trailer (using avcodec_encode_video2 and av_write_frame)
  3. Adjusting our time_base and frame pts values to encode only one frame per second
  4. Removing all variable frame rate code
  5. Numerous other variants that I won't bother you with here

  In creating my project, I've also followed the following tutorials :

  • Dr. Anger's FFMPEG tutorial
  • FFmpeg's Own Tutorials
  • An older tutorial from FFmpeg

  And consulted the deprecated ffmpeg functions list

  And compiled FFMPEG on ubuntu according to the official doc

  And consulted numerous StackOverflow questions :

  • Raw H264 frames in mpegts container using libavcodec
  • How to encode Bitmaps into a video using MediaCodec ?
  • How to convert RGB from YUV420p for ffmpeg encoder ?
  • Encoding H.264 video using FFmpeg C API
  • ffmpeg : how to save h264 raw data as mp4 file

  But every run of the program runs into the exact same problem.

  My question is, is there anything obvious that causes a programmatic run of FFMpeg to differ from a console run (e.g., an incomplete finalization, some threading issues, etc.) ? Like some obvious reason that a console run could repair a corrupted file ? Or is there a decent tool/method for inspecting a video file and finding the point of corruption ?