af_scaletempo2: truncate final packet to expected length

Avoid generating too much audio after EOF.

Note: This often has no effect, because less audio is produced than
required.

Usually this comes to effect with the userspeed filter at high speed
(4x) and going back to 1x speed to remove the filter.

1 files changed, 14 insertions, 0 deletions

diff --git a/audio/filter/af_scaletempo2.c b/audio/filter/af_scaletempo2.c
index 5258fe3204..ea4b63975e 100644
--- a/audio/filter/af_scaletempo2.c
+++ b/audio/filter/af_scaletempo2.c
@@ -111,6 +111,20 @@ static void process(struct mp_filter *f)
             double frame_delay = mp_scaletempo2_get_latency(&p->data, p->speed)
                 + out_samples * p->speed;
             mp_aframe_set_pts(out, pts - frame_delay / mp_aframe_get_effective_rate(out));
+
+            if (p->sent_final) {
+                double remain_pts = pts - mp_aframe_get_pts(out);
+                double rate = mp_aframe_get_effective_rate(out) / p->speed;
+                int max_samples = MPMAX(0, (int) (remain_pts * rate));
+                // truncate final packet to expected length
+                if (out_samples >= max_samples) {
+                    out_samples = max_samples;
+
+                    // reset the filter to ensure it stops generating audio
+                    // and mp_scaletempo2_frames_available returns false
+                    mp_scaletempo2_reset(&p->data);
+                }
+            }
         }
 
         mp_aframe_set_size(out, out_samples);