ffmpeg: do not fail when options are routed to libavformat and libavcodec and only one can be used

Fixes setting frame_size for pulse demuxer
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

ffmpeg_opt.c

@@ -915,8 +915,13 @@ static int open_input_file(OptionsContext *o, const char *filename)
         const AVClass *class = avcodec_get_class();
         const AVOption *option = av_opt_find(&class, e->key, NULL, 0,
                                              AV_OPT_SEARCH_CHILDREN | AV_OPT_SEARCH_FAKE_OBJ);
-        if (!option)
+        const AVClass *fclass = avformat_get_class();
+        const AVOption *foption = av_opt_find(&fclass, e->key, NULL, 0,
+                                             AV_OPT_SEARCH_CHILDREN | AV_OPT_SEARCH_FAKE_OBJ);
+        if (!option || foption)
             continue;
+
+
         if (!(option->flags & AV_OPT_FLAG_DECODING_PARAM)) {
             av_log(NULL, AV_LOG_ERROR, "Codec AVOption %s (%s) specified for "
                    "input file #%d (%s) is not a decoding option.\n", e->key,