@@ -1757,7 +1757,8 @@ static int opt_target(void *optctx, const char *opt, const char *arg)

             for (j = 0; j < nb_input_files; j++) {

                 for (i = 0; i < input_files[j]->nb_streams; i++) {

                     AVCodecContext *c = input_files[j]->ctx->streams[i]->codec;

-                    if (c->codec_type != AVMEDIA_TYPE_VIDEO)

+                    if (c->codec_type != AVMEDIA_TYPE_VIDEO ||

+                        !c->time_base.num)

                         continue;

                     fr = c->time_base.den * 1000 / c->time_base.num;

                     if (fr == 25000) {