From b97d61f924eef1a8930f80cd43d0733c12f67f35 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Tue, 19 Feb 2013 15:00:01 +0100
Subject: [PATCH] avfilter/ff_merge_formats: only merge if doing so does not
loose chroma or alpha
Fixes Ticket1280
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libavfilter/formats.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/libavfilter/formats.c b/libavfilter/formats.c
index 0284db21190..eb9d94022cc 100644
--- a/libavfilter/formats.c
+++ b/libavfilter/formats.c
@@ -92,10 +92,29 @@ do {
AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b)
{
AVFilterFormats *ret = NULL;
+ int i, j;
+ int alpha1=0, alpha2=0;
+ int chroma1=0, chroma2=0;
if (a == b)
return a;
+ for (i = 0; i < a->format_count; i++)
+ for (j = 0; j < b->format_count; j++) {
+ const AVPixFmtDescriptor *adesc = av_pix_fmt_desc_get(a->formats[i]);
+ const AVPixFmtDescriptor *bdesc = av_pix_fmt_desc_get(b->formats[j]);
+ alpha2 |= adesc->flags & bdesc->flags & PIX_FMT_ALPHA;
+ chroma2|= adesc->nb_components > 1 && bdesc->nb_components > 1;
+ if (a->formats[i] == b->formats[j]) {
+ alpha1 |= adesc->flags & PIX_FMT_ALPHA;
+ chroma1|= adesc->nb_components > 1;
+ }
+ }
+
+ // If chroma or alpha can be lost through merging then do not merge
+ if (alpha2 > alpha1 || chroma2 > chroma1)
+ return NULL;
+
MERGE_FORMATS(ret, a, b, formats, format_count, AVFilterFormats, fail);
return ret;
--
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