+ } else if (*spec == 'i' && *(spec + 1) == ':') {
+ int stream_id;
+ char *endptr;
+ spec += 2;
+ stream_id = strtol(spec, &endptr, 0);
+ return stream_id == st->id;
+ } else if (*spec == 'm' && *(spec + 1) == ':') {
+ AVDictionaryEntry *tag;
+ char *key, *val;
+ int ret;
+
+ spec += 2;
+ val = strchr(spec, ':');
+
+ key = val ? av_strndup(spec, val - spec) : av_strdup(spec);
+ if (!key)
+ return AVERROR(ENOMEM);
+
+ tag = av_dict_get(st->metadata, key, NULL, 0);
+ if (tag) {
+ if (!val || !strcmp(tag->value, val + 1))
+ ret = 1;
+ else
+ ret = 0;
+ } else
+ ret = 0;
+
+ av_freep(&key);
+ return ret;
+ } else if (*spec == 'u') {
+ AVCodecContext *avctx = st->codec;
+ int val;
+ switch (avctx->codec_type) {
+ case AVMEDIA_TYPE_AUDIO:
+ val = avctx->sample_rate && avctx->channels;
+ if (avctx->sample_fmt == AV_SAMPLE_FMT_NONE)
+ return 0;
+ break;
+ case AVMEDIA_TYPE_VIDEO:
+ val = avctx->width && avctx->height;
+ if (avctx->pix_fmt == AV_PIX_FMT_NONE)
+ return 0;
+ break;
+ case AVMEDIA_TYPE_UNKNOWN:
+ val = 0;
+ break;
+ default:
+ val = 1;
+ break;
+ }
+ return avctx->codec_id != AV_CODEC_ID_NONE && val != 0;