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• ffplay : how does it calculate the fps for playback ?

  21 octobre 2020, par Daniel

  I'm trying to playback a live media (h264) which is produced by a hardware encoder.

  


  The actual desired FPS on the encoder is set to 20, and when checking the logs of the encoder it prints "FPS statistics" every minute :

  


  2020-10-21 17:26:54.787 [  info] video_stream_thread(),video chn 0, fps: 19.989270
2020-10-21 17:27:54.836 [  info] video_stream_thread(),video chn 0, fps: 19.989270
2020-10-21 17:28:54.837 [  info] video_stream_thread(),video chn 0, fps: 20.005924
2020-10-21 17:29:54.837 [  info] video_stream_thread(),video chn 0, fps: 19.989270
2020-10-21 17:30:54.888 [  info] video_stream_thread(),video chn 0, fps: 19.989274
2020-10-21 17:31:54.918 [  info] video_stream_thread(),video chn 0, fps: 19.989264


  


  You can see it's varying, but not too much around 20.

  


  Question1 : Is this normal ? Or it should be exactly 20 every time ? To avoid confusion : I'd like to know if by the standard of H264, can this be accepted as a valid stream or this violates some
rule ?

  


  I'm trying to playback this stream with ffplay :

  


  $ ffplay rtsp://this_stream
Input #0, rtsp, from 'xyz'
  Metadata:
    title           : 
    comment         : substream
  Duration: N/A, start: 0.040000, bitrate: N/A
    Stream #0:0: Video: h264 (Constrained Baseline), yuv420p(progressive), 640x360, 25 fps, 25 tbr, 90k tbn, 180k tbc


  


  The thing is that ffplay thinks this is a stream with 25fps. And it also plays 25 frames each sec, causing the stream to stall and buffer in every few seconds.

  


  I believe the fps is calculated by some pts/dts values in the stream itself, and it's not hardcoded. Am I wrong here ?

  


  If I'm not wrong, why does ffplay thinks this stream runs at 25fps, whereas it only runs at (around) 20 ?

  


• ffmpeg Error : Pattern type 'glob' was selected but globbing is not support ed by this libavformat build

  14 septembre 2017, par Aryan Naim

  I’m trying to convert group of ".jpg" files acting as individual frames into 1 single mpeg video ".mp4"

  Example parameters i used :

  frame duration  = 2 secs
  
  frame rate      = 30  fps
  
  encoder         = libx264 (mpeg)
  
  input pattern   = "*.jpg"
  
  output pattern  = video.mp4

  Based on ffmpeg wiki instructions at (https://trac.ffmpeg.org/wiki/Create%20a%20video%20slideshow%20from%20images), I issued this command :

  ffmpeg -framerate 1/2 -pattern_type glob -i "*.jpg" -c:v libx264 -r 30 -pix_fmt yuv420p video.mp4

  But I’m getting this error :

  [image2 @ 049ab120] Pattern type 'glob' was selected but globbing is not 
  
  supported by this libavformat build *.jpg: Function not implemented

  Which probably means the API pattern matching commands for my build/version have changed. By the way this my windows 32bit ffmpeg download build (ffmpeg-20150702-git-03b2b40-win32-static).

  How can I choose a group of files using pattern matching using ffmpeg ?

• Still can't install pygame on ubuntu

  1er octobre 2016, par brotheroflogan

  I’ve tried three different ways. The most recent was following instructions here : http://www.pygame.org/wiki/CompileUbuntu

  But when I type in the first line

  sudo apt-get install mercurial python-dev python-numpy ffmpeg \

  I am told that

  E: Package 'ffmpeg' has no installation candidate.

  I continue on with the instructions and I am later told that some of the dependencies are missing (even though those are the ones I had attempted to install moments ago).

  Then when I put in

  sudo python3 setup.py install

  it tells me

  src/_pygame.h:80:20: fatal error: Python.h: No such file or directory
  
   #include 
  
                      ^
  
  compilation terminated.
  
  error: command 'i686-linux-gnu-gcc' failed with exit status 1