[FFmpeg-devel] [PATCH 1/2] avcodec/x86/pngdsp: fix off by 1 error

Michael Niedermayer michaelni at gmx.at
Sun Dec 7 12:52:52 CET 2014


This fixes artifacts in the last pixel of rows with some widths and pixel formats

Found-by: Dominique Leroux <Dominique.Leroux at autodesk.com>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
---
 libavcodec/pngdec.c       |    2 +-
 libavcodec/x86/pngdsp.asm |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index e6b7593..293c7db 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -274,7 +274,7 @@ static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
              * the last pixel with bpp=3 */
             int w = bpp == 4 ? size : size - 3;
             if (w > i) {
-                dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
+                dsp->add_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
                 i = w;
             }
         }
diff --git a/libavcodec/x86/pngdsp.asm b/libavcodec/x86/pngdsp.asm
index 678a032..7bd1ab5 100644
--- a/libavcodec/x86/pngdsp.asm
+++ b/libavcodec/x86/pngdsp.asm
@@ -157,7 +157,7 @@ cglobal add_png_paeth_prediction, 5, 7, %1, dst, src, top, w, bpp, end, cntr
     movh            [dstq], m3
     add               dstq, bppq
     cmp               dstq, endq
-    jle .loop
+    jl .loop
 
     mov               dstq, [rsp]
     dec              cntrq
-- 
1.7.9.5



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