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

[Reimar Döffinger]

On Sat, Jan 17, 2015 at 11:35:41AM -0800, Philip Langdale wrote:
> There is a long sad story behind all this, but it's somewhat ambiguous as to
> whether DVD content should be treated as 720 pixels wide or 704 pixels, with
> 16 pixels cut off. If you decide is should be 704 pixels wide, you need to
> adjust the sample aspect ratio to keep the final display aspect ratio correct.
> 
> For reasons we are not privy too, nvidia decided that the nvenc encoder should
> apply this aspect correction, whether you want it to or not. (I guess there
> might be a flag for it, but if there is it's not documented). So, if you want
> to transcode DVD content at the original size, you need to adjust the aspect
> ratio information you pass to the encoder to compensate for their 'correction'.
> 
> This 'correction' is only applied to 720x480 and 720x576 content - and it does
> so regardless of the input aspect ratio.

Oh my god, this is so horribly broken I vote for doing a "return
-EBROKENAPI" and tell them we'll enable this when NVidia fixes their
stuff.
IMHO some features are not worth the hacks necessary.