[FFmpeg-devel] [PATCH 2/2] examples/decode_filter_video: Add loop for draining the filtergraph

[Stefano Sabatini]

On date Wednesday 2024-03-27 11:51:31 +0100, Tobias Rapp wrote:
> Depending on the filters used the filtergraph can produce trailing data
> after feeding it the last input frame. Update the example to include the
> necessary loop for draining the filtergrap.
> 
> Signed-off-by: Tobias Rapp <t.rapp at noa-archive.com>
> ---
>  doc/examples/decode_filter_video.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/doc/examples/decode_filter_video.c b/doc/examples/decode_filter_video.c
> index 454c192..a57e6df 100644
> --- a/doc/examples/decode_filter_video.c
> +++ b/doc/examples/decode_filter_video.c
> @@ -276,6 +276,25 @@ int main(int argc, char **argv)
>          }
>          av_packet_unref(packet);
>      }

> +    if (ret == AVERROR_EOF) {
> +        /* signal EOF to the filtergraph */
> +        if (av_buffersrc_add_frame_flags(buffersrc_ctx, NULL, 0) < 0) {
> +            av_log(NULL, AV_LOG_ERROR, "Error while closing the filtergraph\n");
> +            goto end;
> +        }
> +
> +        /* pull remaining frames from the filtergraph */
> +        while (1) {
> +            ret = av_buffersink_get_frame(buffersink_ctx, filt_frame);

> +            if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
> +                break;

how are we supposed to handle the EAGAIN case? Shouldn't this be a
sleep and retry?