Support for DAR setting (display aspect ratio)?

General Discussions
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1

Hi everyone,
I have some video files (old TV shows) that have a pixel resolution that is different from the correct aspect ratio. In particular, the video has 854x480 pixel, but the correct aspect ratio is 4:3.

The files have the correct DAR (display aspect ratio) set in the metadata:

$ ffmpeg -i videofile 
...
Stream #0:0: Video: h264 (Main), yuv420p(progressive), 854x480 [SAR 1:1 DAR 427:240], SAR 191:255 DAR 81557:61200, 25 fps, 25 tbr, 1k tbn, 50 tbc (default)
...

Playing the videos on my computer with vlc/mpv/mplayer/… all shows the videos in correct 4:3 resolution.

Playing the videos via Plex gives a widescreen look and everyone gets really fat.

Are these settings not supported by Plex? I.e., is it necessary to recode video files to that the pixel resolution fits perfectly to the expected aspect ratio?

Thanks

Norbert

2

Which Plex player app are you using?

3

Plex Web as well as Android client. Both display the video not in 4:3 format.

4

I think that your files are probably MKV, and have used the aspect ratio setting tags for the video track. That’s the only time that I have seen the double entries for SAR and DAR in ffmpeg. Most players use only those vales contained within the square brackets. An MKV that doesn’t force an aspect ratio doesn’t have the second entries.

854x480 [SAR 1:1 DAR 427:240]

If you do the math, 427/240 = 1.779 (approx 16:9) aspect.

It looks to me like your video was encoded with a 16:9 aspect, but a 4:3 aspect was forced during the muxing within the MKV container. Probably an unusual way of encoding :thinking:

Unfortunately, I don’t think Plex uses any of the tags available within an MKV file except the language tags, and possibly the “forced” tag.

5

Yes, this doesn’t make sense to me. A 4:3 video from a DVD should have a display of 640x480 when being encoded.

@npreining, did you encode these videos yourself?

6

HI all,
thanks for your comments, I try to answer your questions

  • no, I haven’t encoded the videos myself, they come from youtube
  • yes, the info I sent was from a .mkv, but the same happens with .mp4:
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Wickie und die starken Männer - s09e014 - Sturm auf die Festung-4sPA8JZjJCw.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
  Duration: 00:22:57.29, start: 0.000000, bitrate: 648 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 800x480 [SAR 1:1 DAR 5:3], 517 kb/s, SAR 4:5 DAR 4:3, 25 fps, 25 tbr, 90k tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler

From what you said it seems the best way is to re-encode the files into 640x480 settings SAR to 1:1 and DAR to 4:3. I did this and the resulting files work perfectly in Plex, no problem. I just thought there is a way around without re-encoding the files.

Unfortunately it seems that ffmpeg does not allow chaning SAR/DAR without reencoding.

Best

Norbert

7

I have a similar issue, although in my case widescreen footage is showing as 4:3

I recorded files with a hardware .ts encoder 720x576
These are then converted with Video Redo TV suite 5 to be mp4 (same video and audio codecs) and the 16:9 flag is set. It doesn’t re-encode in this setup.
Playing these on Firefox results in 4:3 playback even though I check info on the file in plex and it reports AR of 1.78
Could we not have a force resolution option in the player to avoid re-encoding everything?

regards
Lozzy_uk