[FFmpeg-cvslog] avfilter/f_loop: fix length of aloop leftover buffer

[Marton Balint]

ffmpeg | branch: release/5.1 | Marton Balint <cus at passwd.hu> | Sun Nov  3 22:32:51 2024 +0100| [ff0f25a1546f434f8bfddfed150ea6fa60d62d93] | committer: Marton Balint

avfilter/f_loop: fix length of aloop leftover buffer

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>
(cherry picked from commit b33a59416072ad31a5840f33f9975d88acf45add)

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ff0f25a1546f434f8bfddfed150ea6fa60d62d93
---

 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 672aa4c8f7..b228a93137 100644
--- a/libavfilter/f_loop.c
+++ b/libavfilter/f_loop.c
@@ -150,14 +150,13 @@ 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);