[vlc-devel] [vlc-commits] picture: round the number of visible lines to the upper multiple

[Rémi Denis-Courmont]

Le maanantaina 16. huhtikuuta 2018, 20.13.36 EEST Tristan Matthews a écrit :
> On Mon, Apr 16, 2018 at 12:27 PM, Steve Lhomme <robux4 at ycbcr.xyz> wrote:
> > Le 16/04/2018 à 16:56, Tristan Matthews a écrit :
> >> On Mon, Apr 16, 2018 at 10:38 AM, Steve Lhomme <git at videolan.org> wrote:
> >>> vlc | branch: master | Steve Lhomme <robux4 at ycbcr.xyz> | Mon Apr 16
> >>> 15:35:23 2018 +0200| [82f649983443292bd893962cac0484b7df8d1c89] |
> >>> committer: Steve Lhomme
> >>> 
> >>> picture: round the number of visible lines to the upper multiple
> >> 
> >> This breaks make check for me:
> >> 
> >> FAIL: chroma_copy_sse_test
> >> ==========================
> >> 
> >> testing: 1 x 1 (vis: 1 x 1) NV12 -> I420
> > 
> > So if having 1 line of U/V planes is wrong I assume it used 0 before my
> > patch. How can this be correct ?
> 
> I believe it makes sense for a 1x1 4:2:0 video to have 0 chroma lines
> here, otherwise you would be implicitly converting to 4:4:4 in this
> case, right?

I don't really see how/why one line should be any different than larger odd 
number of lines. Plus, my gut tells me that adding a special case will only 
move the problem.

The real question is, what does it mean to have an odd number of lines with 
4:2:0 sampling. It is valid? And if so, should the chroma be rounded down or 
up?

-- 
Реми Дёни-Курмон
http://www.remlab.net/