Recherche avancée

Sur d’autres sites (8379)

• avconv "select" filter doesn't discard first frames

  1er avril 2014, par user2152106

  I'm trying to segment a video using avconv's "select" filter to extract only a specific range of frames from the input file. As an example, imagine I have a 60fps video file called input.mp4, with 3000 frames (i.e. 50 seconds), and I run

  avconv -i input.mp4 -vf "select='lt(n,2000)'" output1.mp4
  
  avconv -i input.mp4 -vf "select='gte(n,2000)'" output2.mp4

  What I expect is that output1.mp4 has the first 2000 frames of input.mp4 (and lasts 33 seconds), and output2.mp4 has the last 1000 (and lasts 17 seconds).

  I count the frames by running

  avconv -i video.mp4 -vcodec copy -an -f null /dev/null 2>&1 | grep 'frame='

  and checking the value assigned to 'frame'.

  What I actually get, is that output1.mp4 has 2000 frames and lasts 33 seconds, but output2.mp4 has 2999 frames, and still lasts the full 50 seconds. When I open output2.mp4, I notice that the first 2000 frames of the video are actually just a repetition of the 2000th frame of the input, i.e. the first 2000 frames seem to be correctly filtered, but replaced by the first of the accepted frames.

  This is not a pts problem. I check the number of packets and their relative pts using avprobe :

  avprobe -show_packets output2.mp4
  
  echo $(avprobe -show_packets output2.mp4 2>/dev/null | grep PACKET | wc -l)/2 | bc

  I see that there are actually 2999 packets.

  What am I doing wrong ?

  Side questions :

  • Assuming I'm doing something wrong, why does output2.mp4 contain 2999 rather than the full 3000 ?
  • The behaviour doesn't change whether I use the "gte" or "gt" function in the filter. Why could that be ?

• ffserver Error writing frame to output

  28 mars 2014, par GarciaPL

  I am new to ffmpeg and ffserver. I spent a lot of time to stream the .avi file using ffserver. Below is my config.

  Port 8090                      # Port to bind the server to
  
  BindAddress 0.0.0.0
  
  MaxHTTPConnections 2000
  
  MaxClients 1000
  
  MaxBandwidth 10000             # Maximum bandwidth per client
  
                                 # set this high enough to exceed stream bitrate
  
  CustomLog -
  
  NoDaemon                       # Remove this if you want FFserver to daemonize after start
  
  
  
  RTSPPort 7654
  
  RTSPBindAddress 0.0.0.0
  
  
  
  <feed>               # This is the input feed where FFmpeg will send
  
     File ./feed1.ffm            # video stream.
  
     FileMaxSize 1G              # Maximum file size for buffering video
  
     ACL allow 127.0.0.1
  
     ACL allow 192.168.0.0 192.168.0.255
  
  </feed>
  
  
  
  <stream>
  
      Format avi
  
      Feed feed1.ffm
  
  
  
      VideoCodec libvpx
  
      VideoFrameRate 30
  
      VideoBitRate 800
  
      VideoSize 720x576
  
  
  
      AudioCodec aac
  
      Strict -2
  
      AudioBitRate 128
  
      AudioChannels 2
  
      AudioSampleRate 44100
  
      AVOptionAudio flags +global_header
  
  </stream>
  
  
  
  <stream>            # Server status URL
  
     Format status
  
     ACL allow localhost          
  
     ACL allow 192.168.0.0 192.168.255.255
  
  </stream>
  
  
  
  <redirect>    # Just an URL redirect for index, Redirect index.html to the appropriate site
  
     URL http://www.ffmpeg.org/
  
  </redirect>

  So, to start my ffserver I use this command :

  ffserver -d -f ffserver.conf

  and after that I start stream of this avi file using ffmpeg :

  ffmpeg -re -i russian.avi -c:v libx264 -loop 1 http://192.168.1.165:8090/feed1.ffm

  unfortunately I received two errors repeated many of times :

  Too large number of skipped frames 60120709615 > 60000
  
  Error writing frame to output

  I searched the entire internet....but I found nothing what would be valuable.

• ffmpeg continous file stream or live stream

  17 novembre 2019, par shrw

  I work in a news channel. and the use case is little common.
  Where we have ads lined up. Let’s say 1000 ads in the entire day. ads are usually gif files overlay of 100 pixels X 500 pixels and usually less than 10 seconds.
  then we need to either play mp4 files or stream live content.
  What i really want is to :

  1. if we have 30 mp4 files to play in the entire day and 1000 gif overlay ads.
  2. Is it possible to switch(with the help of any coding languale like node.js or linux commands)
     streams from file to live stream.