When fading, always interpolate the more visible half.

diff --git a/player.cpp b/player.cpp
index 0e5b225798988be9c9c8615c56b8ca8c74b24091..5c142ead63f1dfb98dbf8c35e47d3a8a00f3a185 100644 (file)
--- a/player.cpp
+++ b/player.cpp
@@ -120,19 +120,29 @@ got_clip:
                                }
                        }
 
-                       // TODO: If more than half-way through the fade, interpolate the next clip
-                       // instead of the current one.
-
+                       int primary_stream_idx = stream_idx;
                        int secondary_stream_idx = -1;
-                       int64_t secondary_pts = -1;
                        float fade_alpha = 0.0f;
+                       if (got_next_clip) {
+                               secondary_stream_idx = next_clip.stream_idx;
+                               fade_alpha = 1.0f - time_left_this_clip / next_clip_fade_time;
+
+                               // If more than half-way through the fade, interpolate the next clip
+                               // instead of the current one, since it's more visible.
+                               if (fade_alpha >= 0.5f) {
+                                       swap(primary_stream_idx, secondary_stream_idx);
+                                       fade_alpha = 1.0f - fade_alpha;
+                               }
+                       }
+
+                       int64_t secondary_pts = -1;
                        if (got_next_clip) {
                                int64_t in_pts_lower, in_pts_upper;
-                               bool ok = find_surrounding_frames(in_pts, next_clip.stream_idx, &in_pts_lower, &in_pts_upper);
+                               bool ok = find_surrounding_frames(in_pts, secondary_stream_idx, &in_pts_lower, &in_pts_upper);
                                if (ok) {
-                                       secondary_stream_idx = next_clip.stream_idx;
                                        secondary_pts = in_pts_lower;
-                                       fade_alpha = 1.0f - time_left_this_clip / next_clip_fade_time;
+                               } else {
+                                       secondary_stream_idx = -1;
                                }
                        }
 
@@ -144,7 +154,7 @@ got_clip:
                        }
 
                        int64_t in_pts_lower, in_pts_upper;
-                       bool ok = find_surrounding_frames(in_pts, stream_idx, &in_pts_lower, &in_pts_upper);
+                       bool ok = find_surrounding_frames(in_pts, primary_stream_idx, &in_pts_lower, &in_pts_upper);
                        if (!ok || in_pts_upper >= clip.pts_out) {
                                break;
                        }
@@ -164,12 +174,12 @@ got_clip:
                        }
 
                        if (in_pts_lower == in_pts_upper) {
-                               destination->setFrame(stream_idx, in_pts_lower, /*interpolated=*/false, secondary_stream_idx, secondary_pts, fade_alpha);
+                               destination->setFrame(primary_stream_idx, in_pts_lower, /*interpolated=*/false, secondary_stream_idx, secondary_pts, fade_alpha);
                                if (video_stream != nullptr) {
                                        if (secondary_stream_idx == -1) {
-                                               video_stream->schedule_original_frame(pts, stream_idx, in_pts_lower);
+                                               video_stream->schedule_original_frame(pts, primary_stream_idx, in_pts_lower);
                                        } else {
-                                               video_stream->schedule_faded_frame(pts, stream_idx, in_pts_lower, secondary_stream_idx, secondary_pts, fade_alpha);
+                                               video_stream->schedule_faded_frame(pts, primary_stream_idx, in_pts_lower, secondary_stream_idx, secondary_pts, fade_alpha);
                                        }
                                }
                                continue;
@@ -181,12 +191,12 @@ got_clip:
                        for (int64_t snap_pts : { in_pts_lower, in_pts_upper }) {
                                double snap_pts_as_frameno = (snap_pts - in_pts_origin) * output_framerate / TIMEBASE / speed;
                                if (fabs(snap_pts_as_frameno - frameno) < 0.01) {
-                                       destination->setFrame(stream_idx, snap_pts, /*interpolated=*/false, secondary_stream_idx, secondary_pts, fade_alpha);
+                                       destination->setFrame(primary_stream_idx, snap_pts, /*interpolated=*/false, secondary_stream_idx, secondary_pts, fade_alpha);
                                        if (video_stream != nullptr) {
                                                if (secondary_stream_idx == -1) {
-                                                       video_stream->schedule_original_frame(pts, stream_idx, snap_pts);
+                                                       video_stream->schedule_original_frame(pts, primary_stream_idx, snap_pts);
                                                } else {
-                                                       video_stream->schedule_faded_frame(pts, stream_idx, snap_pts, secondary_stream_idx, secondary_pts, fade_alpha);
+                                                       video_stream->schedule_faded_frame(pts, primary_stream_idx, snap_pts, secondary_stream_idx, secondary_pts, fade_alpha);
                                                }
                                        }
                                        in_pts_origin += snap_pts - in_pts;
@@ -209,12 +219,12 @@ got_clip:
                        if (video_stream == nullptr) {
                                // Previews don't do any interpolation.
                                assert(secondary_stream_idx == -1);
-                               destination->setFrame(stream_idx, in_pts_lower, /*interpolated=*/false, fade_alpha);
+                               destination->setFrame(primary_stream_idx, in_pts_lower, /*interpolated=*/false, fade_alpha);
                        } else {
                                // Calculate the interpolated frame. When it's done, the destination
                                // will be unblocked.
-                               destination->setFrame(stream_idx, pts, /*interpolated=*/true, secondary_stream_idx, secondary_pts, fade_alpha);
-                               video_stream->schedule_interpolated_frame(pts, stream_idx, in_pts_lower, in_pts_upper, alpha, secondary_stream_idx, secondary_pts, fade_alpha);
+                               destination->setFrame(primary_stream_idx, pts, /*interpolated=*/true, secondary_stream_idx, secondary_pts, fade_alpha);
+                               video_stream->schedule_interpolated_frame(pts, primary_stream_idx, in_pts_lower, in_pts_upper, alpha, secondary_stream_idx, secondary_pts, fade_alpha);
                        }
                }