shithub: libvpx

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ref: b4957234af20f07c4fc15873ec0590aba17e7cf5
parent: 1e753387c837fa1be82b5fcc9b2879e5e8decd09
author: Johann <[email protected]>
date: Tue Nov 4 05:46:24 EST 2014

Avoid divide-by-zero in vp8 initialization

Check that the numerator is not zero. If it is, guess 30fps.

Fixes a clang IOC error in the quantize test. It's very unlikely for
this to occur in the wild because the setup in the quantize test is very
nonstandard.

Change-Id: Icdab7b81d4e168d3423e14db20787f960052e0c3

--- a/vp8/encoder/onyx_if.c
+++ b/vp8/encoder/onyx_if.c
@@ -1363,15 +1363,20 @@
     cm->version = oxcf->Version;
     vp8_setup_version(cm);
 
-    /* frame rate is not available on the first frame, as it's derived from
+    /* Frame rate is not available on the first frame, as it's derived from
      * the observed timestamps. The actual value used here doesn't matter
-     * too much, as it will adapt quickly. If the reciprocal of the timebase
-     * seems like a reasonable framerate, then use that as a guess, otherwise
-     * use 30.
+     * too much, as it will adapt quickly.
      */
-    cpi->framerate = (double)(oxcf->timebase.den) /
-                     (double)(oxcf->timebase.num);
+    if (oxcf->timebase.num > 0) {
+      cpi->framerate = (double)(oxcf->timebase.den) /
+                       (double)(oxcf->timebase.num);
+    } else {
+      cpi->framerate = 30;
+    }
 
+    /* If the reciprocal of the timebase seems like a reasonable framerate,
+     * then use that as a guess, otherwise use 30.
+     */
     if (cpi->framerate > 180)
         cpi->framerate = 30;