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[Cellar] Mapping of MOV clean aperture values to Matroska

Kieran O Leary <kieran.o.leary@gmail.com> Fri, 23 November 2018 09:56 UTC

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From: Kieran O Leary <kieran.o.leary@gmail.com>
Date: Fri, 23 Nov 2018 09:56:36 +0000
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Subject: [Cellar] Mapping of MOV clean aperture values to Matroska
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Hi,

Would I be correct in saying that ideally, Clean Aperture values in a
MOV/MPEG-4 file should map to the PixelCrop element in Matroska?

I'm asking about this in regards to this ffmpeg ticket -
https://trac.ffmpeg.org/ticket/7437
As it appears that FFmpeg does not currently read the values in the
clap atom and it also does not map them to Matorksa files when
remuxing. It seems to make the most sense to map them to PixelCrop,
but I'd like to hear it from folks more knowledgable than me.

Another associated issue with the display of these kinds of values is
with VLC as it appears that

1) PixelCrop values in Matroska are not supported by VLC at the moment
- https://trac.videolan.org/vlc/ticket/21192
2) Clean aperture values are not supported by VLC at the moment
https://trac.videolan.org/vlc/ticket/21179

Best,

Kieran O'Leary
Irish Film Institute

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