[FFmpeg-devel] [PATCH 3/4] avfiltergraph: document a catch in request_oldest().

Stefano Sabatini stefasab at gmail.com
Tue Jul 17 23:11:16 CEST 2012


On date Tuesday 2012-07-17 18:13:18 +0200, Nicolas George encoded:
> This one is tricky. Consider a graph with two sink links, A and B.
> request_oldest() requests on A, and A returns EOF. This EOF causes
> a filter to flush pending frames to B; they are unrequested.
> Then request_oldest() moves on to B, and B returns EOF.
> 
> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> ---
>  libavfilter/avfiltergraph.h |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/libavfilter/avfiltergraph.h b/libavfilter/avfiltergraph.h
> index c55b549..0bb6d41 100644
> --- a/libavfilter/avfiltergraph.h
> +++ b/libavfilter/avfiltergraph.h
> @@ -255,6 +255,9 @@ char *avfilter_graph_dump(AVFilterGraph *graph, const char *options);
>   * of a filtergraph, only a convenience function to help drain a filtergraph
>   * in a balanced way under normal circumstances.
>   *
> + * Also note that AVERROR_EOF does not mean that frames did not arrive on
> + * some of the sinks during the process.
> + *

OK, but I had to read the commit message to understand this.

What about:

* Also note that AVERROR_EOF does not mean that frames did not arrive on
* some of the sinks during the process.
* When there are multiple sink links, in case the requested link
* returns an EOF, this may force a filter to flush pending frames
* which are sent to another sink link, although unrequested.

?

Feel free to edit & push.
-- 
FFmpeg = Fascinating Furious Majestic Pure Enlightened Gadget


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