player: limit speed change in display-sync adrop mode

Discontinuities (like toggling fullscreen) can cause multiple frames to
be dropped in succession, which sounds very weird. It's better to drop
some video frames instead to compensate for larger desyncs.

We roughly base it on the maximum allowed speed changes (audio change is
"additional" to the video change to account for deviations when playing
at max. video speed change).

1 files changed, 8 insertions, 0 deletions

diff --git a/player/audio.c b/player/audio.c
index 0204cd8287..12f9d03cb4 100644
--- a/player/audio.c
+++ b/player/audio.c
@@ -154,6 +154,7 @@ void reset_audio_state(struct MPContext *mpctx)
         mp_audio_buffer_clear(mpctx->ao_buffer);
     mpctx->audio_status = mpctx->d_audio ? STATUS_SYNCING : STATUS_EOF;
     mpctx->delay = 0;
+    mpctx->audio_drop_throttle = 0;
     mpctx->audio_stat_start = 0;
 }
 
@@ -554,8 +555,11 @@ void fill_audio_out_buffers(struct MPContext *mpctx, double endpts)
     }
 
     int skip_duplicate = 0; // >0: skip, <0: duplicate
+    double drop_limit =
+        (opts->sync_max_audio_change + opts->sync_max_video_change) / 100;
     if (mpctx->display_sync_active && opts->video_sync == VS_DISP_ADROP &&
         fabs(mpctx->last_av_difference) >= opts->sync_audio_drop_size &&
+        mpctx->audio_drop_throttle < drop_limit &&
         mpctx->audio_status == STATUS_PLAYING)
     {
         int samples = ceil(opts->sync_audio_drop_size * play_samplerate);
@@ -565,6 +569,8 @@ void fill_audio_out_buffers(struct MPContext *mpctx, double endpts)
         skip_duplicate = mpctx->last_av_difference >= 0 ? -samples : samples;
 
         playsize = MPMAX(playsize, samples);
+
+        mpctx->audio_drop_throttle += 1 - drop_limit - samples / play_samplerate;
     }
 
     int status = AD_OK;
@@ -683,6 +689,8 @@ void fill_audio_out_buffers(struct MPContext *mpctx, double endpts)
     assert(played >= 0 && played <= data.samples);
     mp_audio_buffer_skip(mpctx->ao_buffer, played);
 
+    mpctx->audio_drop_throttle -= played / play_samplerate;
+
     dump_audio_stats(mpctx);
 
     mpctx->audio_status = STATUS_PLAYING;