[FFmpeg-cvslog] avcodec/imgconvert: Fix loss mask bug in avcodec_find_best_pix_fmt_of_list()

[heimdallr]

ffmpeg | branch: release/2.8 | heimdallr <heimdallr at ngs.ru> | Sat Mar 31 19:37:23 2018 +0700| [eb8654610927dc3dcacf777b0a8bd52ce6c02431] | committer: Michael Niedermayer

avcodec/imgconvert: Fix loss mask bug in avcodec_find_best_pix_fmt_of_list()

example:

AVPixelFormat pixFmts[] = { AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA };
int loss = 0;
AVPixelFormat best = avcodec_find_best_pix_fmt_of_list(pixFmts, AV_PIX_FMT_BGRA, 1, &loss);

best is AV_PIX_FMT_RGB24. But AV_PIX_FMT_RGBA is better.

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 354b26a3945eadd4ed8fcd801dfefad2566241de)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=eb8654610927dc3dcacf777b0a8bd52ce6c02431
---

 libavcodec/imgconvert.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libavcodec/imgconvert.c b/libavcodec/imgconvert.c
index 39cf58a2d2..0abe6cdf48 100644
--- a/libavcodec/imgconvert.c
+++ b/libavcodec/imgconvert.c
@@ -81,10 +81,14 @@ enum AVPixelFormat avcodec_find_best_pix_fmt_of_list(const enum AVPixelFormat *p
     int i;
 
     enum AVPixelFormat best = AV_PIX_FMT_NONE;
+    int loss;
 
-    for(i=0; pix_fmt_list[i] != AV_PIX_FMT_NONE; i++)
-        best = avcodec_find_best_pix_fmt_of_2(best, pix_fmt_list[i], src_pix_fmt, has_alpha, loss_ptr);
+    for (i=0; pix_fmt_list[i] != AV_PIX_FMT_NONE; i++) {
+        loss = *loss_ptr;
+        best = avcodec_find_best_pix_fmt_of_2(best, pix_fmt_list[i], src_pix_fmt, has_alpha, &loss);
+    }
 
+    *loss_ptr = loss;
     return best;
 }