[FFmpeg-trac] #3631(undetermined:closed): Aspect ratio change in the middle of a video stream

FFmpeg trac at avcodec.org
Sat May 10 18:05:56 CEST 2014

#3631: Aspect ratio change in the middle of a video stream
             Reporter:  mar          |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:  aspect       |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
Changes (by cehoyos):

 * status:  new => closed


 Replying to [comment:7 mar]:
 > However, if I view the jpeg in another viewer (e.g. Firefox or Photoshop
 or the Windows default image viewer) it does not display correctly. And
 also the pixel size is not correct.

 So maybe you used the wrong bug tracker?

 > It seems that the information of the aspect ratio is preserved in the
 jpeg file and that ffplay "stretches" the image when it is displayed

 Note that this is exactly what is done for your input video.

 > (stretching also causes a bit of quality loss).

 The opposite is true afaict (the scaling filter necessary to produce
 output files with sar==1 is not lossless).

 > But the image is not "stretched" by other viewers. Is this saving of the
 aspect ratio in the jpeg a "proprietary" feature used by ffmpeg or are all
 those other vierwers "buggy"?

 It is definitely not "proprietary" but specified for jpeg.
 Please use {{{-vf scale=h=ih:w=sar*iw}}} to produce output files with
 (Sorry if this is not the 100% exact filter command, in any case the scale
 filter is able to produce output files as you want them.)

Ticket URL: <https://trac.ffmpeg.org/ticket/3631#comment:8>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker

More information about the FFmpeg-trac mailing list