player: add complex filter graph support

See --lavfi-complex option.

This is still quite rough. There's no support for dynamic configuration
of any kind. There are probably corner cases where playback might freeze
or burn 100% CPU (due to dataflow problems when interaction with
libavfilter).

Future possible plans might include:
- freely switch tracks by providing some sort of default track graph
  label
- automatically enabling audio visualization
- automatically mix audio or stack video when multiple tracks are
  selected at once (similar to how multiple sub tracks can be selected)

1 files changed, 53 insertions, 0 deletions

diff --git a/player/playloop.c b/player/playloop.c
index 6f4521b32a..9fd465b6a2 100644
--- a/player/playloop.c
+++ b/player/playloop.c
@@ -151,6 +151,16 @@ void add_step_frame(struct MPContext *mpctx, int dir)
 // Clear some playback-related fields on file loading or after seeks.
 void reset_playback_state(struct MPContext *mpctx)
 {
+    if (mpctx->lavfi)
+        lavfi_seek_reset(mpctx->lavfi);
+
+    for (int n = 0; n < mpctx->num_tracks; n++) {
+        if (mpctx->tracks[n]->d_video)
+            video_reset(mpctx->tracks[n]->d_video);
+        if (mpctx->tracks[n]->d_audio)
+            audio_reset_decoding(mpctx->tracks[n]->d_audio);
+    }
+
     reset_video_state(mpctx);
     reset_audio_state(mpctx);
     reset_subtitle_state(mpctx);
@@ -922,6 +932,40 @@ static void handle_segment_switch(struct MPContext *mpctx, bool end_is_new_segme
     }
 }
 
+static void handle_complex_filter_decoders(struct MPContext *mpctx)
+{
+    if (!mpctx->lavfi)
+        return;
+
+    for (int n = 0; n < mpctx->num_tracks; n++) {
+        struct track *track = mpctx->tracks[n];
+        if (!track->selected)
+            continue;
+        if (!track->sink || !lavfi_needs_input(track->sink))
+            continue;
+        if (track->d_audio) {
+            audio_work(track->d_audio);
+            struct mp_audio *fr;
+            int res = audio_get_frame(track->d_audio, &fr);
+            if (res == DATA_OK) {
+                lavfi_send_frame_a(track->sink, fr);
+            } else {
+                lavfi_send_status(track->sink, res);
+            }
+        }
+        if (track->d_video) {
+            video_work(track->d_video);
+            struct mp_image *fr;
+            int res = video_get_frame(track->d_video, &fr);
+            if (res == DATA_OK) {
+                lavfi_send_frame_v(track->sink, fr);
+            } else {
+                lavfi_send_status(track->sink, res);
+            }
+        }
+    }
+}
+
 void run_playloop(struct MPContext *mpctx)
 {
     double endpts = get_play_end_pts(mpctx);
@@ -944,6 +988,8 @@ void run_playloop(struct MPContext *mpctx)
         }
     }
 
+    handle_complex_filter_decoders(mpctx);
+
     handle_cursor_autohide(mpctx);
     handle_vo_events(mpctx);
     handle_heartbeat_cmd(mpctx);
@@ -952,6 +998,13 @@ void run_playloop(struct MPContext *mpctx)
     fill_audio_out_buffers(mpctx, endpts);
     write_video(mpctx, endpts);
 
+    if (mpctx->lavfi) {
+        if (lavfi_process(mpctx->lavfi))
+            mpctx->sleeptime = 0;
+        if (lavfi_has_failed(mpctx->lavfi))
+            mpctx->stop_play = AT_END_OF_FILE;
+    }
+
     handle_playback_restart(mpctx, endpts);
 
     // Use the audio timestamp if no video, or video is enabled, but has ended.