+int check_stream_specifier(AVFormatContext *s, AVStream *st, const char *spec)
+{
+ if (*spec <= '9' && *spec >= '0') /* opt:index */
+ return strtol(spec, NULL, 0) == st->index;
+ else if (*spec == 'v' || *spec == 'a' || *spec == 's' || *spec == 'd') { /* opt:[vasd] */
+ enum AVMediaType type;
+
+ switch (*spec++) {
+ case 'v': type = AVMEDIA_TYPE_VIDEO; break;
+ case 'a': type = AVMEDIA_TYPE_AUDIO; break;
+ case 's': type = AVMEDIA_TYPE_SUBTITLE; break;
+ case 'd': type = AVMEDIA_TYPE_DATA; break;
+ }
+ if (type != st->codec->codec_type)
+ return 0;
+ if (*spec++ == ':') { /* possibly followed by :index */
+ int i, index = strtol(spec, NULL, 0);
+ for (i = 0; i < s->nb_streams; i++)
+ if (s->streams[i]->codec->codec_type == type && index-- == 0)
+ return i == st->index;
+ return 0;
+ }
+ return 1;
+ } else if (!*spec) /* empty specifier, matches everything */
+ return 1;
+
+ av_log(s, AV_LOG_ERROR, "Invalid stream specifier: %s.\n", spec);
+ return AVERROR(EINVAL);
+}
+
+AVDictionary *filter_codec_opts(AVDictionary *opts, enum CodecID codec_id, AVFormatContext *s, AVStream *st)
+{
+ AVDictionary *ret = NULL;
+ AVDictionaryEntry *t = NULL;
+ AVCodec *codec = s->oformat ? avcodec_find_encoder(codec_id) : avcodec_find_decoder(codec_id);
+ int flags = s->oformat ? AV_OPT_FLAG_ENCODING_PARAM : AV_OPT_FLAG_DECODING_PARAM;
+ char prefix = 0;
+
+ if (!codec)
+ return NULL;
+
+ switch (codec->type) {
+ case AVMEDIA_TYPE_VIDEO: prefix = 'v'; flags |= AV_OPT_FLAG_VIDEO_PARAM; break;
+ case AVMEDIA_TYPE_AUDIO: prefix = 'a'; flags |= AV_OPT_FLAG_AUDIO_PARAM; break;
+ case AVMEDIA_TYPE_SUBTITLE: prefix = 's'; flags |= AV_OPT_FLAG_SUBTITLE_PARAM; break;
+ }
+
+ while (t = av_dict_get(opts, "", t, AV_DICT_IGNORE_SUFFIX)) {
+ char *p = strchr(t->key, ':');
+
+ /* check stream specification in opt name */
+ if (p)
+ switch (check_stream_specifier(s, st, p + 1)) {
+ case 1: *p = 0; break;
+ case 0: continue;
+ default: return NULL;
+ }
+
+ if (av_opt_find(avcodec_opts[0], t->key, NULL, flags, 0) ||
+ (codec && codec->priv_class && av_opt_find(&codec->priv_class, t->key, NULL, flags, 0)))
+ av_dict_set(&ret, t->key, t->value, 0);
+ else if (t->key[0] == prefix && av_opt_find(avcodec_opts[0], t->key+1, NULL, flags, 0))
+ av_dict_set(&ret, t->key+1, t->value, 0);
+
+ if (p)
+ *p = ':';
+ }
+ return ret;
+}
+
+AVDictionary **setup_find_stream_info_opts(AVFormatContext *s, AVDictionary *codec_opts)
+{
+ int i;
+ AVDictionary **opts;
+
+ if (!s->nb_streams)
+ return NULL;
+ opts = av_mallocz(s->nb_streams * sizeof(*opts));
+ if (!opts) {
+ av_log(NULL, AV_LOG_ERROR, "Could not alloc memory for stream options.\n");
+ return NULL;
+ }
+ for (i = 0; i < s->nb_streams; i++)
+ opts[i] = filter_codec_opts(codec_opts, s->streams[i]->codec->codec_id, s, s->streams[i]);
+ return opts;
+}
+