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• FFMPEG, itsoffset with overlay command not working as it supposed to

  14 janvier 2014, par G.T.

  I managed to overlay two videos one by another with the overlay command and use a nullsrc command to play both video till both of them ended with the following command :

  ./ffmpeg -i first.MOV -i second.MOV -filter_complex "nullsrc=size=1280x400:duration=30[bg];[0]scale=640:-1,pad=1280:400[first];[bg][first]overlay=0:0[base];[1]scale=640:-1[second];[base][second]overlay=640:0" output.mp4

  Now what I wanted to do is to delay one of the overlay till the other one finishes. For this as far as I know the command is itsoffset, so I modified to use this :

  ./ffmpeg -i first.MOV -itsoffset 5 -i second.MOV -filter_complex "nullsrc=size=1280x400:duration=30[bg];[0]scale=640:-1,pad=1280:400[first];[bg][first]overlay=0:0[base];[1]scale=640:-1[second];[base][second]overlay=640:0" output.mp4

  Now my only problem with this is that I want to show the first frame of the delayed video till it starts... And even though somewhere I read that this should do it, it won't. It leaves it blank till the input starts.

  Any idea how could I add the first frame of second video till the itsoffset starts the video ?

  Update1 : I may found a cheat around it, but the problem with it it's really slow in the first second or so.

  ./ffmpeg -i first.MOV -i second.MOV -itsoffset 5 -i second.MOV -filter_complex "color=size=1280x400:duration=30[bg];[1]select=eq(n\,0),scale=640:-1[fg];[bg][fg]overlay=640:0[bgc];[0]scale=640:-1[first];[bgc][first]overlay=0:0[firstb];[2]scale=640:-1[second];[firstb][second]overlay=640:0" output.mp4

  Not to mention later on I need to dynamically create the command line string which would be really painful like this.

• Seekbar not working in Chrome

  9 janvier 2014, par mbajur

  I have encoded my video with the following settings chain :

  # line breaks are just for better readability
  
  ffmpeg -y -i /path/to/destination.mp4 
  
         -vcodec libx264 
  
         -acodec libfaac 
  
         -s 640x360  
  
         -movflags faststart  
  
         -aspect 1.7777777777777777 
  
         /path/to/source.mp4

  And, for some reason, it broken the ability to use seekbar in Google Chrome (it works good in Safari). What i have noticed is that the videos were working fine when there is no -movflags faststart setting in above chain. Here is an example of video, which is not working :

  http://portalvhdsrwglplr5bdc2k.blob.core.windows.net/vdepot/uploads/video/file/167/mp4_5878a7ab84fb43402106c575658472fa.mp4

  Please note : Seekbar is not working when video download is in progress or it's 100% the first time. If video has been downloaded by chrome player and you refresh the page, seekbar works fine.

• How to load/dump a raw video data into AvFrame structure pointer by using ffmpeg api function

  4 octobre 2016, par Harikrishna

  I want to write an application for encoding raw (yuv) video file data by using ffmpeg api functions instead of using a command.

  So for this, I need to use avcodec_encode_video2 function to encode raw video data and before calling this function all required configurations and video data should be fill on the AVCodecContext and AvFrame structure pointers.

  Can anyone guide me that how can I load this raw video data on AvFrame by using ffmpeg api function ?

  Thank you in advance.