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• split video (avi/h264) on keyframe

  30 novembre 2012, par m.sr

  Hallo.

  I have a big video file. ffmpeg, tcprobe and other tool say, it is an h264-stream in an AVI-container.

  Now i'd like to cut out small chunks form the video.

  1. Problem : The index of the video seam corrupted/destroyed. I kind of fixed this via mplayer -forceidx -saveidx <indexfile> <bigvideofile></bigvideofile></indexfile>. The Problem here is, that I'm now stuck with mplayer/mencoder which can use this index file via -loadidx <indexfile></indexfile>. I have tried correcting the index like described in man aviindex (mplayer -frames 0 -saveidx mpidx broken.avi ; aviindex -i mpidx -o tcindex ; avimerge -x tcindex -i broken.avi -o fixed.avi), but this didn't fix my video - meaning that most tools i've tested couldn't search in the video file.

  2. Problem : I cut out parts of the video via following command : mencoder -loadidx in.idx -ss 8578 -endpos 20 -oac faac -ovc x264 -sws 9 -lavfopts format=mp4 -x264encopts <lotsofopts> -of lavf -vf scale=800:-10,harddup in.avi -o out.mp4</lotsofopts>. Now here the problem is, that some videos are corrupted at the beginning. I think this is because the fact, that i do not necessarily cut at keyframe.

  Questions :

  1. What is the best way to fix the index of an avi "inline" so that every tool can again work as expected with it ?

  2. How can i split at the keyframes ? Is there an mencoder-option for this ?

  3. Are Keyframes coming in a frequency ? How to find out this frequency ? (So with a bit of math it should be possible to calculate the next keyframe and cut there)

  4. Is ther perhaps some completely other way to split this movie ? Doing it by hand is no option, i've to cut out 1000+ chunks ...

  Thanks a lot !

• hevc : deobfuscate slice/tile boundary handling for DBF

  27 juillet 2014, par Anton Khirnov

  hevc : deobfuscate slice/tile boundary handling for DBF
  Use named constants instead of magic numbers, avoid using variables with
  
  inverse meaning from what their name implies.
  

  • [DH] libavcodec/hevc.c
  • [DH] libavcodec/hevc.h
  • [DH] libavcodec/hevc_filter.c

• avformat/rtsp : Fix timeout option

  30 mai 2021, par Andriy Gelman

  avformat/rtsp : Fix timeout option
  92c40ef882be115e72d2aa02f9032b7ce88f8537 added a listen_timeout option
  
  for sdp. This allowed a user to set variable timeout which was
  
  originally hard coded to 10 seconds.
  The commit used the initial_timeout variable to store the value. But
  
  this variable is shared with rtsp where it's used to infer a "listen"
  
  mode. Thus, the timeout value could not be set in rtsp, and the default
  
  value (initial_timeout = -1) would give 100ms timeout.
  This was attempted to be fixed in c8101aabee654f6d147a4d89f77fa73e18908610,
  
  which changed the meaning of initial_timeout = -1 to be an infinite
  
  timeout. However, it did not address the issue that the timeout could
  
  still not be set. Being able to set the timeout is useful because it
  
  allows to automatically reconfigure from a udp to tcp connection in the
  
  lower transport.
  In this commit this is fixed by using the stimeout variable to
  
  store the timeout value.
  Signed-off-by : Andriy Gelman <andriy.gelman@gmail.com>
  

  • [DH] libavformat/rtsp.c
  • [DH] libavformat/rtsp.h