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• FFMpeg UDP streaming - random split video effect

  3 octobre 2014, par Philmacs

  I’m trying to get a simple local preview of my webcam from an FFMpeg udp stream using an embedded Mplayer window. I can view the live stream using MPlayer but the image is unstable. I’m using the following FFMpeg command :

  ffmpeg -f dshow -video_size 640x480 -i video="Lenovo EasyCamera" -an -f rawvideo -pix_fmt yuyv422 -r 15 udp://127.0.0.1:1234

  And this is the MPlayer command :

  mplayer -demuxer rawvideo -rawvideo fps=15:w=640:h=480:format=yuy2 -nofs -noquiet -identify -idle -slave -nomouseinput -framedrop -wid 1051072

  Sometimes the stream image is OK, but intermittently the image tears randomly and this is how it looks (sorry, not enough rep for images in posts)

  http://imgur.com/sLC3FW0

  I have tried with FFPlay to see if it’s a problem with MPlayer, but I get the same result :

  ffplay -s 640x480 -pix_fmt yuyv422 -f rawvideo -i udp://127.0.0.1:1234

  http://imgur.com/06L42Cj

  This effect is happening at random. If I stop and restart the video might be OK, or it may look like the above. Using aything other than udp and rawvideo adds a delay to the video stream, which I want to avoid.

  The FFMpeg streaming guide suggest methods when you get packet loss, but as far as I’m aware I don’t seem to be getting that.

  I’m new to FFMpeg/Mplayer/video streaming and any help or thoughts greatly appreciated.

• ffmpeg fails to capture video running on screen

  21 septembre 2014, par Ralf

  I’m trying to capture a slide presentation as video. I’m using the following command to capture my screen

  ffmpeg \
  
     -f x11grab -s 1024x768 -r 25 -i $DISPLAY \
  
     -f alsa -i pulse \
  
     -vcodec libx264 -preset ultrafast -vb 1000k \
  
     -acodec libmp3lame -ab 128k \
  
     test.avi

  This works (application windows on the screen are visible and sound is recorded in test.avi), but the problem is : Any video shown on the screen (e.g. a youtube video running in a browser window, but also e.g. a video played by mplayer) only appears as an empty (e.g. green) box when I play the captured video (test.avi).

  I’m using ffmpeg version 0.8.16-4:0.8.16-0ubuntu0.12.04.1 on Ubuntu 12.04.5 LTS with the nvidia-331 driver (effect is the same with older nvidia-304).

  I would really appreciate any suggestions, thanks a lot !

• (Cross-platform) FFMPEG based GUI direct stream copy linear video editor [on hold]

  14 octobre 2014, par Fluorescent Hallucinogen

  FFMPEG official site has list of FFMPEG based projects (https://trac.ffmpeg.org/wiki/Projects).

  I use VirtualDub for linear video montage using direct stream copy mode (without recompression). It is GNU GPL licensed, but is designed only for Microsoft Windows and operates only AVI files.

  FFMPEG is excellent cross-platform utility that supports many formats (codecs and containers). It can be used for split and merge video files (not only AVI) using direct stream copy mode, but FFMPEG is console UI application.

  Is there GUI video editor (based on FFMPEG) (cross-platform or maybe only for Linux or maybe only for Windows) that can split and merge video files (not only AVI) using direct stream copy mode and have preview window ?

  Now I use video player, watch the input video file, remember the time for split video to fragments and write console line script for merge these fragments. All work is OK, but it is very inconvenient.

  At the worst, are there players or editors that can generate project file (that contains time markers for split and merge) that can be used with FFMPEG ?