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• FFMPEG : Add black frames at start and end of video

  7 novembre 2014, par user3729198

  Im trying to add 10 second of black frames to the beginning of my clip and 30 seconds of black frames at end of clip. This is what I got so far.

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  ffmpeg -i XX.mp4 -vf "
  
  color=c=black:s=720x576:d=10 [pre] ;
  
  color=c=black:s=720x576:d=30 [post] ;
  
  [pre] [in] [post] concat=n=3" -an -vcodec mpeg2video -pix_fmt yuv422p -s 720v576 -aspect 16:9 -r 25 -minrate 30000k -maxrate 30000k -b 30000k output.mpg

  ---

  It works in some cases. But Only on specific material with right "SAR" values. But most of the time I get this error.

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  Input link in1:v0 parameters (size 720x576, SAR 35:24) do not match the corresponding output link in0:v0 parameters (720x576, SAR 1:1)
  
  [Parsed_concat_2 @ 0x7f9853d048c0] Failed to configure output pad on Parsed_concat_2

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  Is there a way to complement my code or another way to do this ?

• HLS Streaming on IPad with IOS 7 / 8 causes 10 seconds freezed frame - no clue why

  25 juin 2014, par user3747636

  We have a problem with HLS h.264 mp4 on IPad devices using HLS streaming on IOS 7 and 8 :

  The first 9-15 seconds (the length of the first TS segment) only shows the first key frame (IDR) of the second TS segment, while the sound plays normally. When the second segment begins to play, the video continues as it should.

  HLS segmenter is a wowza with 10 seconds segment length. The encoding software we use is TMPG, latest version (uses x264). The funny thing is, that handbrake, xmedia recode, adobe me deliver videos which work. I am aware of the fact, that this hints to a bug within our encoding software, but if someone already had that problem with another software / segmenter combination and fixed it, I would like to know what the source of the problem was.

  What we already tried :

  • changing almost every setting so that it sticks as close as possible to apple’s recommendations
  • changing GOP structure, GOP length, encoding parameters which influence efficiency of encoding
  • analysis of the TS segments created by wowza, they are fine and begin all with keyframes
  • contact TMPG/Apple/Wowza support

  So, did anyone stumble upon this problem before ? Has anyone solved it ?

  EDIT :

  It seems that TMPGEnc uses a defective x264 implementation. The mediastreamvalidator tool from Apple returned an error stating that our TS segment "does not contain any IDR access unit with a SPS and a PPS" - which it does actually, but obviously in the wrong places if that somehow matters.

• FFmpeg, overlay, black detect, intermission — too much to ask ?

  11 avril 2016, par Timo Mika Gläßer

  I have two streams (see the schematic in the picture below). One is the main video-stream which is constantly on and one is a picture-in-picture stream which have intermissions. Both are fed to ffmpeg as live streams and I want to redistribute them as a merged live stream again.

  Is there a way to either have a static image for the picture-in-picture stream when it has no data (i.e. using blackdetect) or completely hiding it temporarily ?