[x264-devel] [patch] x264 --sar in mp4 container

[vmrsss]

Hello.

I find there is something wrong in the way x264 handles --sar with a  
mp4 container. For comparison, let me first run:

> x264 test.yuv 720x576 --crf 18 --sar 64:45 -o test.264 ; MP4Bbox - 
> add test.264 -new test.mp4

Then, I get:

> MP4Box -info test.mp4
>
> Track # 1 Info - TrackID 1 - TimeScale 25 - Duration 00:00:30.040
> Media Info: Language "Undetermined" - Type "vide:avc1" - 751 samples
> MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
> AVC/H264 Video - Visual Size 720 x 576 - Profile Baseline @ Level  
> 5.1 NAL Unit length bits: 32
> Pixel Aspect Ratio 64:45 - Indicated track size 1024 x 576
> Self-synchronized

This is exactly as expected, SAR = 64/45 and DAR=16/9. (Notice the  
"indicated track size" field.) Next, I run

> x264 test.yuv 720x576 --crf 18 --sar 64:45 -o test.mp4

and the "Indicated track size" is wrong:

> MP4Box -info test.mp4 Track # 1 Info - TrackID 1 - TimeScale 25 -  
> Duration 00:00:30.040
> Media Info: Language "Undetermined" - Type "vide:avc1" - 751 samples
> MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
> AVC/H264 Video - Visual Size 720 x 576 - Profile Main @ Level 5.1  
> NAL Unit length bits: 32
> Pixel Aspect Ratio 64:45 - Indicated track size 720 x 576
> Self-synchronized

Inspecting the code shows that in fact the DAR is not computed from  
the frame size and the SAR. The patch attached just does this, and  
then calls a suitable GPAC function to set the "Indicated track size".  
Can this please be considered for inclusion in the build tree?

Cheers,
vmrsss

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