[vlc-devel] [PATCH 3/3] swscale: scale the aspect-ratio of the output format

Felix Abecassis felix.abecassis at gmail.com
Sat Feb 22 16:26:24 CET 2014

2014-02-22 15:37 GMT+01:00 Rémi Denis-Courmont <remi at remlab.net>:
> Well, it's good but it's not great. The transform filter should follow the same
> padding rules as the VLC core with regards to the scan line pitch. 1090 is a
> really bad choice; it is not even a multiple of 4, forget 16 or 32.
Well, this is different, when allocating the picture we use another
pitch. In this case, picture->p[0].i_pitch is 1120, a multiple of 32.
We have two levels of padding, it's quite confusing I think.

> Well ideally the filter chain would be created *before* the video output, so
> that we create artificial format mismatches like that. But OK, patch 1/3 is
> probably fine for the time being.
Yes, we should aim for something like that in the future. Adding a
swscale filter in this case is terribly inefficient.

> Well I don't really care about patch 2/3. But patch 3/3 looks very wrong to
> me.
It's wrong because it's modifying the output format? Why isn't that safe?
As I said it was done this way before, but hidden in the function call

Félix Abecassis

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