From b812db66af160bfac2f64aef2ade4aed7eb76b12 Mon Sep 17 00:00:00 2001
From: Paul B Mahol <onemda@gmail.com>
Date: Fri, 21 Apr 2017 21:44:28 +0200
Subject: [PATCH] utvideodec: Fix gradient prediction when stride does not
match width
Signed-off-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
---
libavcodec/utvideodec.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/libavcodec/utvideodec.c b/libavcodec/utvideodec.c
index 0f58c83979e..ed6368e4cd8 100644
--- a/libavcodec/utvideodec.c
+++ b/libavcodec/utvideodec.c
@@ -686,7 +686,11 @@ static void restore_gradient_planar_il(UtvideoContext *c, uint8_t *src, ptrdiff_
C = bsrc[i - 1];
bsrc[i] = (A - B + C + bsrc[i]) & 0xFF;
}
- for (i = 0; i < width; i++) {
+ A = bsrc[-stride];
+ B = bsrc[-(1 + stride + stride - width)];
+ C = bsrc[width - 1];
+ bsrc[stride] = (A - B + C + bsrc[stride]) & 0xFF;
+ for (i = 1; i < width; i++) {
A = bsrc[i - stride];
B = bsrc[i - (1 + stride)];
C = bsrc[i - 1 + stride];
@@ -784,7 +788,11 @@ static void restore_gradient_packed_il(uint8_t *src, int step, ptrdiff_t stride,
C = bsrc[i - step];
bsrc[i] = (A - B + C + bsrc[i]) & 0xFF;
}
- for (i = 0; i < width * step; i += step) {
+ A = bsrc[-stride];
+ B = bsrc[-(step + stride + stride - width * step)];
+ C = bsrc[width * step - step];
+ bsrc[stride] = (A - B + C + bsrc[stride]) & 0xFF;
+ for (i = step; i < width * step; i += step) {
A = bsrc[i - stride];
B = bsrc[i - (step + stride)];
C = bsrc[i - step + stride];
--
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