shithub: dav1d

Info  •  Files  •  Log  •  Branches

cli: Reduce fps fraction in ivf parsing

Also avoid integer overflows by using 64-bit intermediate precision.

--- a/tools/input/ivf.c

+++ b/tools/input/ivf.c

@@ -28,6 +28,7 @@

 #include "config.h"

 #include <errno.h>

+#include <limits.h>

 #include <stdio.h>

 #include <stdint.h>

 #include <stdlib.h>

@@ -92,8 +93,27 @@

             break; // EOF

         fseeko(c->f, rl32(data) + 8, SEEK_CUR);

     }

-    fps[0] = timebase[0] * *num_frames;

-    fps[1] = timebase[1] * duration;

+

+    uint64_t fps_num = (uint64_t) timebase[0] * *num_frames;

+    uint64_t fps_den = (uint64_t) timebase[1] * duration;

+    if (fps_num && fps_den) { /* Reduce fraction */

+        uint64_t gcd = fps_num;

+        for (uint64_t a = fps_den, b; (b = a % gcd); a = gcd, gcd = b);

+        fps_num /= gcd;

+        fps_den /= gcd;

+

+        while ((fps_num | fps_den) > UINT_MAX) {

+            fps_num >>= 1;

+            fps_den >>= 1;

+        }

+    }

+    if (fps_num && fps_den) {

+        fps[0] = (unsigned) fps_num;

+        fps[1] = (unsigned) fps_den;

+    } else {

+        fps[0] = fps[1] = 0;

+    }

+

     fseeko(c->f, 32, SEEK_SET);

     return 0;