[FFmpeg-cvslog] mov: Do not compute negative SAR values

[Vittorio Giovara]

ffmpeg | branch: master | Vittorio Giovara <vittorio.giovara at gmail.com> | Thu Jan 22 19:10:27 2015 +0000| [4c5fa628da099dbb598c93bc4555b8733d2c3035] | committer: Vittorio Giovara

mov: Do not compute negative SAR values

This partially reverts cf70ba37ba74089a18295b29e77dead0a3222c9e, since
it didn't take into account when rotation is 0, but there is another
valid operation (eg. translation) in the matrix.

Found-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4c5fa628da099dbb598c93bc4555b8733d2c3035
---

 libavformat/mov.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 86b2de0..75bd5e9 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -35,7 +35,6 @@
 #include "libavutil/time_internal.h"
 #include "libavutil/avstring.h"
 #include "libavutil/dict.h"
-#include "libavutil/display.h"
 #include "libavutil/opt.h"
 #include "libavcodec/ac3tab.h"
 #include "avformat.h"
@@ -2579,10 +2578,9 @@ static int mov_read_tkhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     }
 
     // transform the display width/height according to the matrix
-    // skip this if the rotation angle is 0 degrees
+    // skip this when the display matrix is the identity one
     // to keep the same scale, use [width height 1<<16]
-    if (width && height && sc->display_matrix &&
-        av_display_rotation_get(sc->display_matrix) != 0.0f) {
+    if (width && height && sc->display_matrix) {
         for (i = 0; i < 2; i++)
             disp_transform[i] =
                 (int64_t)  width  * display_matrix[0][i] +
@@ -2590,9 +2588,10 @@ static int mov_read_tkhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
                 ((int64_t) display_matrix[2][i] << 16);
 
         //sample aspect ratio is new width/height divided by old width/height
-        st->sample_aspect_ratio = av_d2q(
-            ((double) disp_transform[0] * height) /
-            ((double) disp_transform[1] * width), INT_MAX);
+        if (disp_transform[0] > 0 && disp_transform[1] > 0)
+            st->sample_aspect_ratio = av_d2q(
+                ((double) disp_transform[0] * height) /
+                ((double) disp_transform[1] * width), INT_MAX);
     }
     return 0;
 }