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

Nicolas George george at nsup.org
Sun Jan 18 10:40:24 CET 2015

Le nonidi 29 nivôse, an CCXXIII, Hendrik Leppkes a écrit :
> nvenc should behave the same as libx264, or any other video encoder, if
> this patch makes it do that, then it should be applied.
> If bt601 needs special handling not yet present in avcodec, it should be
> implemented in such a way that all encoders can benefit from it.

That was one of the points I was trying to make, thanks for explaining it
more clearly.

Two additional points:

According to Philip's tests, nvenc adds a 45/44 = 720/704 factor, not
720/702 = 40/39, so it does not conform to BT.601 anyway.

I have downloaded BT.601 from <URL: http://www.itu.int/rec/R-REC-BT.601/ >,
both the most recent and the oldest versions, and I did not find any
explicit reference of this 702 business, nor could I decipher indirect
references, so I still wonder where it comes from exactly.

(I had previously assumed it would be insanely expensive like the MPEG
standards, but it is free and short. On the other hand, I do not expect
people who do not bother to properly configure their character encodings to
produce good standards.)


  Nicolas George
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