• Compression Techniques

  Cropping of the Pillarbox from SD-video

  Posted by Thomas Demirian on September 8, 2014 at 6:12 pm

  I want to crop of the Pillarboxing that is added to SD video when Downscaling from HD. Most software like the Adobe Suit, Final Cut and QuickTime adds 9 frames on each side. The Source is always 720×576 or 720×486 Therefore I use this command for PAL.

  -vf “crop=702:576:9:0,scale=720:576:”

  or

  -vf “crop=702:576:9:0:” and define the output resolution with “-s 720×576”.

  The final Code can look like this.

  ffmpeg -i INPUT.mov -vcodec mpeg2video -aspect 16:9 -r 25 -s 720v576 -vf "crop=702:576:10:0,scale=720:576:" -pix_fmt yuv422p -minrate 30000k -maxrate 30000k -b:v 30000k -bufsize 9437184 -an OUTPUT.mpg

  The problem is that the encoded video is pushed ONE Pixel to the right all the time. Which also means that there is one Column of black pixel to the left. If I do the same but only crop of 8 pixels on each side it seems to be centered just fine.

  Also worth noting is that there are no error messages when I crop 8 pixels on each side. But when I crop 9 Pixels ffmpeg gives me this varning, “Warning: data is not aligned! This can lead to a speedloss”.

  Are there any solutions? Or alternative ways?

  Thomas Demirian replied 11 years, 8 months ago 1 Member · 0 Replies
• 0 Replies

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