Interlace affecting HEVC aspect ratio

#1
Using VRD6 beta 791c, I've taken a 720x576 interlaced MPEG-2 off-air movie clip, and I've encoded it in different ways. All at CRF23.
All encodes produced the same (correct) aspect ratio when played back in VRD or VLC, however my Samsung UHD telly displayed correct height but different widths:-

1. VideoRedo V6/791c, HEVC, interlaced (no change): width very squished to 35%:mad:
2. VideoRedo V6/791c, HEVC, deinterlace (smart or auto): width squished to 70%:mad:
3. VideoRedo V6/791c, H.264, deinterlace (smart or auto): width correct i.e. 100%:giggle:
4. (For comparison) VidCoder v3.16, x265, became deinterlaced: width correct, i.e. 100%:giggle:

MediaInfo for the two VideoRedo HEVC cases were identical, apart from the interlace flag in "Encoding settings".
MediaInfo for the VidCoder comparison was essentially the same again, except the "Bits/(Pixel*Frame)" 0.058 for VidCoder 0.090 for VRD.
The only real difference I could see was VidCoder being on v2.6 of x265 library, versus VRD6 being on v3.0.

A mystery!
TobyW
 
#4
Same 720x576i input file as before, in VideoRedo V6/791c, encoding to HEVC:-
1. Encoded as 1920x1080, interlaced (no change): Width is 35% (as before), PLUS a superimposed flickering ghost image, wider but shorter and wrapped around
2. Encoded as 1920x1080, deinterlaced auto : Width is now 100%, picture is correctly sized to fill the screen! :giggle:
3. Encoded as 1440x1080, deinterlaced auto: Width is 75%.
 
Last edited:

Danr

Administrator
Staff member
#5
tobyW, what about H.264 in V6? Is it possibly an issue with your Samsung playing HEVC deinterlaced material?
 
#6
Hi Dan, thanks for your suggestions.

H.264 in VRD6 works just fine. Display is full size on TV, regardless of interlace or not, and regardless
of resizing from 720x576 to 1440x1080 or to 1920x1080.

My test file had black side bars, so I've re-run all the tests with a different source file, just in case.
Same results as before. However one new thing showed up:-

I encoded the new source file as HEVC, size SAS, deinterlace=auto.
Now, although MediaInfo did show "interlace=0" in the Encoding settings, the output was
visibly still interlaced on the PC, and the picture was squished to around 35% width on the TV.

On setting deinterlace=smart, the deinterlace looked OK, although the width was still only 70%.
I wonder whether something funny is going on, to do with VRD6's deinterlacing?

As far as the Samsung TV is concerned, my only other source of HEVC material has been VidCoder
(Handbrake wrapper), but the TV has never had a problem playing those files, deinterlaced or not.

Just thinking aloud, could anything be amiss with the pixel aspect ratio arrangements, either in VRD's code
or in your x265 library? (E.g. I recently tripped over a bug in VidCoder's x265 lib.)
 

Danr

Administrator
Staff member
#7
Tobyw, Post the media info here for handbrake file and the deinterlaced video file let's see what the differences are.
 
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