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• FFMPEG SAR mismatch when concatenating videos

  6 septembre 2020, par marcman

  I'm trying to concatenate videos with different codecs using the concat filter. I'm also doing a bunch of processing to scale and pad the individual clips in this filter as well. However, I keep getting an error of this form :

  


  [Parsed_concat_14 @ 0x556b918ed580] Input link in1:v0 parameters (size 960x1280, SAR 0:1) do not match the corresponding output link in0:v0 parameters (1280x720, SAR 1:1)


  


  Here is my command :

  


  ffmpeg \
    -y \
    -loglevel warning \
    -stats \
    -i videos/vid0.mp4 \
    -i videos/vid1.mp4 \
    -i videos/vid2.mov \
    -filter_complex \
"[0:v]setpts=PTS-STARTPTS, scale=1920:1080, setsar=1, drawtext=expansion=strftime: basetime=$(date +%s -d'2020-07-10 16:04:44')000000 : fontcolor=white : text='%^b %d, %Y%n%l\\:%M%p' : fontsize=36 : y=1080-4*lh : x=1920-text_w-2*max_glyph_w; \
[1:v]setpts=PTS-STARTPTS, scale=810:1080, pad=width=1920:height=1080:x=555:y=0:color=black, setsar=1, drawtext=expansion=strftime: basetime=$(date +%s -d'2020-08-20 21:12:27')000000 : fontcolor=white : text='%^b %d, %Y%n%l\\:%M%p' : fontsize=36 : y=1080-4*lh : x=1365-text_w-2*max_glyph_w; \
[2:v]setpts=PTS-STARTPTS, scale=607:1080, pad=width=1920:height=1080:x=656:y=0:color=black, setsar=1, drawtext=expansion=strftime: basetime=$(date +%s -d'2020-08-27 16:42:26')000000 : fontcolor=white : text='%^b %d, %Y%n%l\\:%M%p' : fontsize=36 : y=1080-4*lh : x=1263-text_w-2*max_glyph_w; \
[0:v][0:a][1:v][1:a][2:v][2:a]concat=n=3:v=1:a=1[v][a]" \
    -map "[v]" \
    -map "[a]" \
    videos.mp4


  


  This gives the following error :

  


  [Parsed_concat_14 @ 0x563ab9d840c0] Input link in1:v0 parameters (size 960x1280, SAR 0:1) do not match the corresponding output link in0:v0 parameters (1280x720, SAR 1:1)
[Parsed_concat_14 @ 0x563ab9d840c0] Input link in2:v0 parameters (size 1080x1920, SAR 0:1) do not match the corresponding output link in0:v0 parameters (1280x720, SAR 1:1)


  


  The input videos have these resolutions :

  


  

  1. vid0.mp4 : (1280x720)

  


  2. vid1.mp4 : (960x1280)

  


  3. vid2.mp4 : (1080x1920)

  


  


  The output resolution of the concatenated output is to be 1920x1080.

  


  I've added the setsar=1 command after all my scaling and padding operations, as per this question and answer. I've also tried setdar=16/9 as in this answer, but it made no difference.

  


  What am I missing here ?

  


• Is there a way to extract a video frame, encode a sentence behind it, put it back, and then decode it ?

  29 juillet 2021, par Jesse Hix

  I am trying to do stenography on an MP4 video where I am pulling a frame out at a certain time, 5.52 sec, saving that frame as a jpg or jpeg using any image stenography tool, in this case stegosuite, to encode a sentence behind the image and then reinsert that image back into the video at the same time and then extract it again with the same command and using the same steno tool read the message.

  


  Up until decoding the message everything runs without issue.
I know that it is not working because the videos are not the same in size meaning that the frankenstein video is not the same as the original and thus messing up the frame extraction.

  


  Question :
  Is there a way to extract a frame encode a sentence behind it put it back and then decode it ?

  


  What I tried :
  
Used to extract the frame both times :

  


  ffmpeg -ss 5.52 -i original.mp4 -vframes 1 frames_%d.jpg


  


  Used to combine the image back into the video :

  


  ffmpeg -i original.mp4 -i frames_1_embed.jpg -filter_complex "[1]setpts=5.52/TB[im];[0][im]overlay=eof_action=pass" -c:a copy out_1.mp4


  


• Revision 6253cc9279 : Speed setting review. Substantial reworking of the speed vs quality trade offs

  1er octobre 2013, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_onyx_if.c

  
   Modify /vp9/encoder/vp9_onyx_int.h

  
   Modify /vp9/encoder/vp9_rdopt.c

  
  
  Speed setting review.

  Substantial reworking of the speed vs quality trade offs for
  speed 1 and 2.

  In this patch I am attempting to freeze the "quality" meaning of
  speeds 1 and 2 relative to speed 0 so that in future we can
  better evaluate progress.

  I am targeting :
  Speed 1 quality -5% vs speed 0.
  Speed 2 quality -10% vs speed 0

  It is inevitable that quality will still fluctuate a little as we adjust
  settings and add new features, but we will attempt to keep as
  close as possible to these values. Above speed 2 things will remain
  a bit more fluid for now.

  In this patch speed 1 is approximately 4-5x as fast as speed 0. This
  is similar to before but the quality hit is a lot less. Likewise speed 2
  is approximately 2x as fast as speed 1 but is similar in quality to the
  previous speed 1 configuration.

  Also slight change to behavior of FLAG_EARLY_TERMINATE to insure
  all reference frames get at least one rd test. Important for very low
  variance regions.

  WIP :- Added a new speed level with old speed 4 becoming speed 5.
  Speed 3 and 4 tradeoffs still WIP

  Change-Id : Ic7a38dd7b5b63ab1501f9352411972f480ac6264