[FFmpeg-devel] [PATCH] nvenc: Compensate for hardware trying to mess with aspect ratio of DVD content.

Nicolas George george at nsup.org
Sat Jan 17 21:42:43 CET 2015

L'octidi 28 nivôse, an CCXXIII, Kieran Kunhya a écrit :
> BT601 makes this very clear. The active picture is 702 pixels.

There are two fundamental flaws with your reasoning:

First, BT601 only applies to a some kind of videos. Wikipedia tells me it
applies to "encoding interlaced analog video signals in digital video form";
do you think it is wrong? For all other kind of videos, all this nonsense is
just irrelevant.

Second, and that is more important, the SAR→DAR conversion is not a matter
of conforming to a certain video standard, it is a matter of basic
arithmetic. Arithmetic has been around a lot longer than BT601, or any
industrial standard for video. If you have a "BT601 720ish×576 16/9 video",
then SAR must be (16/9) / (702/576) = 512/351, nothing else; reversely, if
the SAR is 64/45, that means the video is really 720×576 for 16/9 without
any nonsense.


  Nicolas George
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