diff options
| -rw-r--r-- | libavfilter/avfiltergraph.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c index 860f1d8..c5a9e3b 100644 --- a/libavfilter/avfiltergraph.c +++ b/libavfilter/avfiltergraph.c @@ -316,12 +316,24 @@ static int formats_declared(AVFilterContext *f) return 1; } +/** + * Perform one round of query_formats() and merging formats lists on the + * filter graph. + * @return >=0 if all links formats lists could be queried and merged; + * AVERROR(EAGAIN) some progress was made in the queries or merging + * and a later call may succeed; + * AVERROR(EIO) (may be changed) plus a log message if no progress + * was made and the negotiation is stuck; + * a negative error code if some other error happened + */ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx) { int i, j, ret; int scaler_count = 0, resampler_count = 0; - int count_queried = 0, count_merged = 0, count_already_merged = 0, - count_delayed = 0; + int count_queried = 0; /* successful calls to query_formats() */ + int count_merged = 0; /* successful merge of formats lists */ + int count_already_merged = 0; /* lists already merged */ + int count_delayed = 0; /* lists that need to be merged later */ for (i = 0; i < graph->nb_filters; i++) { AVFilterContext *f = graph->filters[i]; @@ -464,6 +476,11 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx) if (count_delayed) { AVBPrint bp; + /* if count_queried > 0, one filter at least did set its formats, + that will give additional information to its neighbour; + if count_merged > 0, one pair of formats lists at least was merged, + that will give additional information to all connected filters; + in both cases, progress was made and a new round must be done */ if (count_queried || count_merged) return AVERROR(EAGAIN); av_bprint_init(&bp, 0, AV_BPRINT_SIZE_AUTOMATIC); |
