[FFmpeg-cvslog] avcodec/bmp: Analyze BGRA files alpha channel to choose pixel format

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Sep 10 16:06:14 2015 +0200| [aec340c533293d6230573aaf3fe22a74e5454b99] | committer: Michael Niedermayer

avcodec/bmp: Analyze BGRA files alpha channel to choose pixel format

BGRA BMPs commonly do contain an all transparent alpha channel

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=aec340c533293d6230573aaf3fe22a74e5454b99
---

 libavcodec/bmp.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/libavcodec/bmp.c b/libavcodec/bmp.c
index 42270da..3019d01 100644
--- a/libavcodec/bmp.c
+++ b/libavcodec/bmp.c
@@ -337,6 +337,20 @@ static int bmp_decode_frame(AVCodecContext *avctx,
             return AVERROR_INVALIDDATA;
         }
     }
+    if (avctx->pix_fmt == AV_PIX_FMT_BGRA) {
+        for (i = 0; i < avctx->height; i++) {
+            int j;
+            uint8_t *ptr = p->data[0] + p->linesize[0]*i + 3;
+            for (j = 0; j < avctx->width; j++) {
+                if (ptr[4*j])
+                    break;
+            }
+            if (j < avctx->width)
+                break;
+        }
+        if (i == avctx->height)
+            avctx->pix_fmt = p->format = AV_PIX_FMT_BGR0;
+    }
 
     *got_frame = 1;