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• FFPMEG : stream local file to UDP address, make client aware about video length and current frame time offset (make stream seekable ?)

  10 décembre 2014, par klim

  Just started to use FFMPEG. This is a really great library which is capable of video life transcoding and streaming.

  I use following commands to transcode and stream local video file to UDP address :
  ffmpeg -y -re -i inputvideo.mpeg2 -vsync 1 -vcodec mpeg4 -b 1600k -r 15 -crf 20 -acodec aac -ar 44100 -strict -2 -f mpegts udp ://192.168.1.30:1234

  It works smooth. I can open this udp address in VLC player and play life stream.

  Does anybody know how to make client aware about video duration and current time stamp ?

  Ideally would be nice to make stream seekable, as far as I understand it is not possible, but at least I would like to tell VLC client the total duration of the video and current frame time stamp, so it could show the progress.

  Thanks.

• concatenate video files using ffmpeg - garbled images but audio okay

  2 décembre 2014, par anonygrits

  I am trying to concatenate video files so that next one follows the one before it when it is played. The formatting for all of the files are the same. The files all have audio & video.

  I think I am very close (hopefully !) to getting this to work, but I have one final problem. The command below takes all of the mp4 files in my folder and creates a big mp4 file, which is the right size in total MB, but the images for all videos after the first video are garbled. The audio is okay (continues just fine from video to video). Also, I don’t get any error messages.

  ffmpeg -f concat -i <(for f in /folder1/*.mp4; do echo "file '$f'"; done) -c copy /folder1/all.mp4

  I’m not very familiar with ffmpeg yet, so I’ve just been trying the different suggestions I’ve found on the web. Can anyone suggest other things for me to try ? (I’ve tried reading the FAQs, but I have to confess that I don’t fully understand it. Also, there seems to be some posts about audio being missing after concatenation, but I haven’t seen anything on images being garbled.) Thx in advance !

• lavu : fix memory leaks by using a mutex instead of atomics

  14 novembre 2014, par wm4

  lavu : fix memory leaks by using a mutex instead of atomics
  The buffer pool has to atomically add and remove entries from the linked
  
  list of available buffers. This was done by removing the entire list
  
  with a CAS operation, working on it, and then setting it back again
  
  (using a retry-loop in case another thread was doing the same thing).
  This could effectively cause memory leaks : while a thread was working on
  
  the buffer list, other threads would allocate new buffers, increasing
  
  the pool’s total size. There was no real leak, but since these extra
  
  buffers were not needed, but not free’d either (except when the buffer
  
  pool was destroyed), this had the same effects as a real leak. For some
  
  reason, growth was exponential, and could easily kill the process due
  
  to OOM in real-world uses.
  Fix this by using a mutex to protect the list operations. The fancy
  
  way atomics remove the whole list to work on it is not needed anymore,
  
  which also avoids the situation which was causing the leak.
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DH] libavutil/buffer.c
  • [DH] libavutil/buffer_internal.h