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• FFMPEG video overlay with remote overlay source

  19 mai 2012, par Dasas

  I'm trying to achive an overlay with ffmpeg wich take the overlay source from a "remote" video encoder.

  Just for the sake of testing i'm using random online video source.

  As you will notice in the code below the source and the overlay are the same. That's not the problem.

  The command i'm using at the moment is the following :

  ffmpeg -f mjpeg -i http://81.20.148.158/anony/mjpg.cgi  -vf "movie=http://81.20.148.158/anony/mjpg.cgi [mv]; [in][mv] overlay=0:0" output.avi

  Here an easy-to-read version :

  ffmpeg 
  
  -f mjpeg
  
  -i http://81.20.148.158/anony/mjpg.cgi  
  
  -vf "movie=http://81.20.148.158/anony/mjpg.cgi [mv]; [in][mv] overlay=0:0" 
  
  output.avi

  I'm getting this error :

  Missing key or no key/value separator found after key '//81.20.148.158/anony/mjpg.cgi'

  It works pretty well if i use a "local" video source such as

  ffmpeg 
  
  -f mjpeg
  
  -i http://81.20.148.158/anony/mjpg.cgi  
  
  -vf "movie=a.flv [mv]; [in][mv] overlay=0:0" 
  
  output.avi

  I have the feeling something is wrong with the double slashes // or more likely with the : in http://...

  Thanks,
  Francesco.

• Best Web Video Encoding Practices for IOS (FFMpeg)

  21 juin 2012, par MagicMushroom

  I am working on an online video repository system for a client, written mostly in PHP. At the moment I am building a mobile version of our desktop website. Our desktop site allows users to watch videos in the browser, much like YouTube.

  My client uploads videos through the manager interface I have created, and my application uses FFmpeg on the server to transcode his videos into several resolutions and bitrates. I am no expert on FFmpeg, and while I do not know the ins and outs of each individual setting, I do understand how it works as a whole. Right now, we are using the mp4 container format with the h.264 codec to encode our videos. Our command looks like :

  ffmpeg -y -i "INPUT FILE.mov" -f mp4 -s 640x480 -vcodec libx264 -preset fast -maxrate 1500 -bitrate 1000 -bufsize 4096 -acodec libfaac -ab 192 -ac 2 "OUTPUT_FILE.mp4" >> "FILE.log" 2>&1 &

  I'm hoping to gain information about best practices with encoding video for web streaming on IOS and other mobile devices using FFmpeg. What resolutions and settings make for good mobile streaming video ? How can I ensure maximum compatibility across the sea of Android devices ?

• python multiprocessing and ffmpeg corrupts files

  1er juillet 2012, par misterte

  I'm currently trying to convert several videos to three different outputs, all using ffmpeg : mp4, webm and jpeg. I also need to run this script in different directories and create within the directories webm, mp4 and jpeg subdirectories where the respective converted files are stored.

  I am running the following script inside a directory with 8 .mov test files in it. Files work ok as .mov.

  (It's a bit long, so here you can view it online)

  The script creates all files and directories. I can also note that all Consumer processes take tasks and complete them. The problem is resulting .mp4 and .webm files are corrupted.

  Here you can see an example output. It's a bit long, so I think it's best if I point out the part I think is relevant.

  ...
  
  [h264 @ 0x121815a00]no frame!
  
  Error while decoding stream #0.0
  
  [h264 @ 0x121815a00]AVC: nal size -6554108
  
  [h264 @ 0x121815a00]no frame!
  
  Error while decoding stream #0.0
  
  [h264 @ 0x121815a00]AVC: nal size 391580264
  
  [h264 @ 0x121815a00]no frame!
  
  ...

  This does not happen if I run ffmpeg straight from the console.

  ffmpeg -i movie.mov -b 500k -s 640x360 -padtop 60 -padbottom 60 movie_out.webm

  I can even run it in parallel shells and the output will not be affected.

  Can anyone see what the problem is ?

  thnx !

  A.