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• fps is too low when ffmpeg grab video

  6 avril 2014, par zhangyp007

  I use ffmpeg with the following options :

  ffmpeg -f video4linux2 -s 640x480 -r 25 -i /dev/video0 http://localhost:8090/feed1.ffm

  All I want to do is to watch the web live video in my chrome browser. This is relevant part in my ffserver.conf file :

  <stream>              # Output stream URL definition
  
     Feed feed1.ffm              # Feed from which to receive video
  
     Format webm
  
     NoAudio
  
      #Audio settings
  
     #AudioCodec vorbis
  
     #AudioBitRate 64             # Audio bitrate
  
  
  
     # Video settings
  
     VideoCodec libvpx            
  
     VideoSize 720*576           # Video resolution 
  
     VideoFrameRate 25           # Video FPS
  
     AVOptionVideo flags +global_header  # Parameters passed to encoder
  
                                         # (same as ffmpeg command-line parameters)
  
     AVOptionVideo cpu-used 0
  
     AVOptionVideo qmin 10
  
     AVOptionVideo qmax 42
  
     AVOptionVideo quality good
  
     AVOptionAudio flags +global_header
  
     PreRoll 15
  
     StartSendOnKey
  
     VideoBitRate 400            # Video bitrate
  
  </stream>

  When I open chrome to the following location :

  http://localhost:8090/test.webm

  I can successfully watch the live video, but due to a low fps, I just doesn't produce a fluent video. I found out that the fps is only around 6. Sometimes it goes up to around 10 or 15. When that is the case, the becomes video a bit more fluent.

  I have set the fps to 25, so I wonder why it actually gets to the low fps reate.

• avfilter/formats : Don't typedef structure a second time

  11 septembre 2020, par Andreas Rheinhardt

  avfilter/formats : Don't typedef structure a second time
  Before commit 2f76476549a01ae2c4ec2a440e4b14c5aba64869, avfilter.h
  
  contained no typedef for AVFilterChannelLayouts ; all references to it
  
  were done using its struct tag. formats.h meanwhile contained the
  
  definition of the struct and a typedef for it. Said commit now added a
  
  typedef in avfilter.h, too, bringing it in line with AVFilterFormats ;
  
  yet this means that there are two typedefs for AVFilterChannelLayouts
  
  (in contrast to AVFilterFormats which is only typedef'ed in avfilter.h).
  The problem is that older versions of GCC don't like this and error out :
  
  http://fate.ffmpeg.org/history.cgi?slot=x86_64-openbsd5.6-gcc4.2-conf2
  
  is one of the FATE boxes that now fail to compile. So just remove the
  
  typedef in formats.h.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Reviewed-by : Nicolas George <george@nsup.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/formats.h

• avcodec/mjpegenc : Reconstify mjpeg encoder

  10 mars, par Andreas Rheinhardt

  avcodec/mjpegenc : Reconstify mjpeg encoder
  It has been deconstified in 2c2dfd914902d0b41b4bd30d4b19ae08af1d7bc1
  
  because the FFCodec is touched in av_codec_init_static because
  
  of its get_supported_config callback. Yet this is easily remedied :
  
  Only call get_supported_config to set pix_fmts if the codec does
  
  not already have it set.
  This also fixes a mismatch between the declaration of ff_mjpeg_encoder
  
  in allcodecs.c and the definition in mjpegenc.c. Said mismatch is
  
  actually undefined behaviour.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/allcodecs.c
  • [DH] libavcodec/mjpegenc.c