avcodec/mpeg4videodec: Fix runtime error: signed integer overflow: -135088512...

avcodec/mpeg4videodec: Fix runtime error: signed integer overflow: -135088512 * 16 cannot be represented in type 'int'

Fixes: 736/clusterfuzz-testcase-5580263943831552

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/mpeg4videodec.c

@@ -387,11 +387,21 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
 
         }
         for (i = 0; i < 2; i++) {
+            int64_t sd[2] = {
+                s->sprite_delta[i][0] - a * (1LL<<16),
+                s->sprite_delta[i][1] - a * (1LL<<16)
+            };
+
             if (llabs(s->sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL)) >= INT_MAX ||
                 llabs(s->sprite_offset[0][i] + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX ||
                 llabs(s->sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL) + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX ||
                 llabs(s->sprite_delta[i][0] * (w+16LL)) >= INT_MAX ||
-                llabs(s->sprite_delta[i][1] * (w+16LL)) >= INT_MAX
+                llabs(s->sprite_delta[i][1] * (w+16LL)) >= INT_MAX ||
+                llabs(sd[0]) >= INT_MAX ||
+                llabs(sd[1]) >= INT_MAX ||
+                llabs(s->sprite_offset[0][i] + sd[0] * (w+16LL)) >= INT_MAX ||
+                llabs(s->sprite_offset[0][i] + sd[1] * (h+16LL)) >= INT_MAX ||
+                llabs(s->sprite_offset[0][i] + sd[0] * (w+16LL) + sd[1] * (h+16LL)) >= INT_MAX
             ) {
                 avpriv_request_sample(s->avctx, "Overflow on sprite points");
                 goto overflow;