[FFmpeg-devel] [PATCH 2/4] avfilter/f_loop: fix length of aloop leftover buffer

[Marton Balint]

On Mon, 4 Nov 2024, James Almer wrote:

> On 11/4/2024 5:30 PM, Marton Balint wrote:
>>  If the audio loop stops inside an audio frame, the leftover buffer
>>  contains the
>>  end of the frame, which is not looped. The length supposed to be the part
>>  which
>>  was not written to the loop buffer, so we need to drain exactly that
>>  number of
>>  bytes from the leftover buffer.
>>
>>  Signed-off-by: Marton Balint <cus at passwd.hu>
>>  ---
>>    libavfilter/f_loop.c | 5 ++---
>>    1 file changed, 2 insertions(+), 3 deletions(-)
>>
>>  diff --git a/libavfilter/f_loop.c b/libavfilter/f_loop.c
>>  index 9b01a85405..3372c77fee 100644
>>  --- a/libavfilter/f_loop.c
>>  +++ b/libavfilter/f_loop.c
>>  @@ -170,14 +170,13 @@ static int afilter_frame(AVFilterLink *inlink,
>>  AVFrame *frame)
>>                    s->pts += av_rescale_q(s->start - s->ignored_samples,
>>                (AVRational){1, outlink->sample_rate}, outlink->time_base);
>>                }
>>                s->nb_samples += ret - drain;
>>  -            drain = frame->nb_samples - written;
>>  -            if (s->nb_samples == s->size && drain > 0) {
>>  +            if (s->nb_samples == s->size && frame->nb_samples > written)
>>  {
>>                    int ret2;
>>
>>                    ret2 = av_audio_fifo_write(s->left, (void
>>                    **)frame->extended_data, frame->nb_samples);
>>                    if (ret2 < 0)
>>                       return ret2;
>>  -                av_audio_fifo_drain(s->left, drain);
>>  +                av_audio_fifo_drain(s->left, written);
>>                }
>>                frame->nb_samples = ret;
>>                s->pts += av_rescale_q(ret, (AVRational){1,
>>                outlink->sample_rate}, outlink->time_base);
>
> Does this fix ticket #11283?
>

It is not clear which problem the ticket is referring to, this one (which 
is a very old issue), or the newer one, which was fixed by the next patch 
in the series. To fix the ticket (by every interpretation) you need both 
fixes.

Regards,
Marton