[SCM] libav/experimental: png: disable broken MMX/SIMD code for bpp <= 2

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit 2257165bff243534982f4ddabae4e65e2a35f2ab
Author: Vittorio Giovara <vittorio.giovara at gmail.com>
Date:   Fri Aug 1 19:13:55 2014 +0100

    png: disable broken MMX/SIMD code for bpp <= 2
    
    The decoder was producing different results when ASM was disabled.
    Based on a long debug session with Kostya.

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 7bc2ad4..0c4c91a 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -240,7 +240,7 @@ static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
             p      = last[i];
             dst[i] = p + src[i];
         }
-        if (bpp > 1 && size > 4) {
+        if (bpp > 2 && size > 4) {
             /* would write off the end of the array if we let it process
              * the last pixel with bpp=3 */
             int w = bpp == 4 ? size : size - 3;

-- 
Libav/FFmpeg packaging