Michael Niedermayer wrote:
On Mon, Feb 06, 2017 at 05:14:14PM +0200, Maksym Veremeyenko wrote:
Hi,
Attached patch fixes chroma positioning during scaling interlaced 4:2:0.
On a first iteration default context value been overwritten by new
value and not been update on next iterations for fields. This mean
that vertical chroma position remain 128 for field#0 and field#1
instead of *64* and *192*.
Attached patch use local variable for storing this intermediate
value of chroma vertical position not modifying default context
value.
--
Maksym Veremeyenko
vf_scale.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
6a3a3966939dd87c45a8e124b0364da30b02728b
0001-Fix-chroma-positioning-for-4-2-0-pixel-format.patch
From 912ecf538b6b2f7a8df4afdfed2d34052162335c Mon Sep 17 00:00:00 2001
From: Maksym Veremeyenko <ve...@m1.tv>
Date: Mon, 6 Feb 2017 17:03:17 +0200
Subject: [PATCH] Fix chroma positioning for 4:2:0 pixel format
applied
thx
Nice, testing wise it raises a question to how swscale should work by
default with interl=1 and 420 to rgb (maybe other cases as well).
In summary this patch will appear to fail with a test like.
ffmpeg -i 420-interlaced.ts -ss 11.2 -vf scale=interl=1 -vframes 1 out.png
Will look just as broken as before the patch. The addition of -
-sws_flags +accurate_rnd
fixes it, adding +full_chroma_int looks better still.
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