From 8919e39eca6caa673bb7cde70dbd34fd1e484010 Mon Sep 17 00:00:00 2001 From: "Steinar H. Gunderson" Date: Wed, 11 Mar 2020 19:58:54 +0100 Subject: [PATCH] Refactor the handling of the various time origins in Player into a class. --- futatabi/player.cpp | 111 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 91 insertions(+), 20 deletions(-) diff --git a/futatabi/player.cpp b/futatabi/player.cpp index 19868f4..d168a9d 100644 --- a/futatabi/player.cpp +++ b/futatabi/player.cpp @@ -106,6 +106,82 @@ void do_splice(const vector &new_list, size_t playing_index1, ssize_ old_list->insert(old_list->end(), new_list.begin() + splice_start_new_list, new_list.end()); } +// Keeps track of the various timelines (wall clock time, output pts, +// position in the clip we are playing). Generally we keep an origin +// and assume we increase linearly from there; the intention is to +// avoid getting compounded accuracy errors, although with double, +// that is perhaps overkill. (Whenever we break the linear assumption, +// we need to reset said origin.) +class TimelineTracker +{ +public: + struct Instant { + steady_clock::time_point wallclock_time; + int64_t in_pts; + int64_t out_pts; + int64_t frameno; + }; + + TimelineTracker(double master_speed, int64_t out_pts_origin) + : master_speed(master_speed), last_out_pts(out_pts_origin) { + origin.out_pts = out_pts_origin; + } + + void new_clip(steady_clock::time_point wallclock_origin, const Clip *clip, int64_t start_pts_offset) + { + this->clip = clip; + origin.wallclock_time = wallclock_origin; + origin.in_pts = clip->pts_in + start_pts_offset; + origin.out_pts = last_out_pts; + origin.frameno = 0; + } + + // Returns the current time for said frame. + Instant advance_to_frame(int64_t frameno); + + int64_t get_in_pts_origin() const { return origin.in_pts; } + bool playing_at_normal_speed() const { + const double effective_speed = clip->speed * master_speed; + return effective_speed >= 0.999 && effective_speed <= 1.001; + } + + void snap_by(int64_t offset) { + origin.in_pts += offset; + } + + void change_master_speed(double new_master_speed, Instant now); + +private: + double master_speed; + const Clip *clip = nullptr; + Instant origin; + int64_t last_out_pts; +}; + +TimelineTracker::Instant TimelineTracker::advance_to_frame(int64_t frameno) +{ + Instant ret; + double in_pts_double = origin.in_pts + TIMEBASE * clip->speed * (frameno - origin.frameno) * master_speed / global_flags.output_framerate; + ret.in_pts = lrint(in_pts_double); + double out_pts_double = origin.out_pts + TIMEBASE * (frameno - origin.frameno) / global_flags.output_framerate; + ret.out_pts = lrint(out_pts_double); + ret.wallclock_time = origin.wallclock_time + microseconds(lrint((out_pts_double - origin.out_pts) * 1e6 / TIMEBASE)); + ret.frameno = frameno; + + last_out_pts = ret.out_pts; + + return ret; +} + +void TimelineTracker::change_master_speed(double new_master_speed, Instant now) +{ + master_speed = new_master_speed; + + // Reset the origins, since the calculations depend on linear interpolation + // based on the master speed. + origin = now; +} + } // namespace void Player::play_playlist_once() @@ -114,7 +190,6 @@ void Player::play_playlist_once() bool clip_ready; steady_clock::time_point before_sleep = steady_clock::now(); string pause_status; - float master_speed = start_master_speed; // Wait until we're supposed to play something. { @@ -160,15 +235,15 @@ void Player::play_playlist_once() should_skip_to_next = false; // To make sure we don't have a lingering click from before play. steady_clock::time_point origin = steady_clock::now(); // TODO: Add a 100 ms buffer for ramp-up? - int64_t in_pts_origin = clip_list[0].clip.pts_in; + TimelineTracker timeline(start_master_speed, pts); + timeline.new_clip(origin, &clip_list[0].clip, /*pts_offset=*/0); for (size_t clip_idx = 0; clip_idx < clip_list.size(); ++clip_idx) { const Clip *clip = &clip_list[clip_idx].clip; const Clip *next_clip = (clip_idx + 1 < clip_list.size()) ? &clip_list[clip_idx + 1].clip : nullptr; - int64_t out_pts_origin = pts; double next_clip_fade_time = -1.0; if (next_clip != nullptr) { - double duration_this_clip = double(clip->pts_out - in_pts_origin) / TIMEBASE / clip->speed; + double duration_this_clip = double(clip->pts_out - timeline.get_in_pts_origin()) / TIMEBASE / clip->speed; double duration_next_clip = double(next_clip->pts_out - next_clip->pts_in) / TIMEBASE / clip->speed; next_clip_fade_time = min(min(duration_this_clip, duration_next_clip), clip->fade_time_seconds); } @@ -182,25 +257,22 @@ void Player::play_playlist_once() lock_guard lock(frame_mu); // Find the first frame such that frame.pts <= in_pts. - auto it = find_last_frame_before(frames[stream_idx], in_pts_origin); + auto it = find_last_frame_before(frames[stream_idx], timeline.get_in_pts_origin()); if (it != frames[stream_idx].end()) { - in_pts_origin = it->pts; + timeline.snap_by(it->pts - timeline.get_in_pts_origin()); } } steady_clock::time_point next_frame_start; for (int64_t frameno = 0; !should_quit; ++frameno) { // Ends when the clip ends. - double out_pts = out_pts_origin + TIMEBASE * frameno / global_flags.output_framerate; - next_frame_start = - origin + microseconds(lrint((out_pts - out_pts_origin) * 1e6 / TIMEBASE)); - int64_t in_pts = lrint(in_pts_origin + TIMEBASE * frameno * clip->speed * master_speed / global_flags.output_framerate); - pts = lrint(out_pts); + TimelineTracker::Instant instant = timeline.advance_to_frame(frameno); + int64_t in_pts = instant.in_pts; + pts = instant.out_pts; + next_frame_start = instant.wallclock_time; float new_master_speed = change_master_speed.exchange(0.0f / 0.0f); if (!std::isnan(new_master_speed)) { - master_speed = new_master_speed; - in_pts_origin = in_pts - TIMEBASE * frameno * clip->speed * master_speed / global_flags.output_framerate; - out_pts_origin = out_pts - TIMEBASE * frameno / global_flags.output_framerate; + timeline.change_master_speed(new_master_speed, instant); } if (should_skip_to_next.exchange(false)) { // Test and clear. @@ -214,7 +286,7 @@ void Player::play_playlist_once() // Only play audio if we're within 0.1% of normal speed. We could do // stretching or pitch shift later if it becomes needed. - bool play_audio = clip->speed * master_speed >= 0.999 && clip->speed * master_speed <= 1.001; + const bool play_audio = timeline.playing_at_normal_speed(); { lock_guard lock(queue_state_mu); @@ -234,7 +306,7 @@ void Player::play_playlist_once() // (or we may have gone from no new clip to having one, or the other way). next_clip = (clip_idx + 1 < clip_list.size()) ? &clip_list[clip_idx + 1].clip : nullptr; if (next_clip != nullptr) { - double duration_this_clip = double(clip->pts_out - in_pts) / TIMEBASE / clip->speed; + double duration_this_clip = double(clip->pts_out - timeline.get_in_pts_origin()) / TIMEBASE / clip->speed; double duration_next_clip = double(next_clip->pts_out - next_clip->pts_in) / TIMEBASE / clip->speed; next_clip_fade_time = min(min(duration_this_clip, duration_next_clip), clip->fade_time_seconds); } @@ -369,7 +441,7 @@ void Player::play_playlist_once() display_single_frame(primary_stream_idx, snap_frame, secondary_stream_idx, secondary_frame, fade_alpha, next_frame_start, /*snapped=*/true, subtitle, play_audio); - in_pts_origin += snap_frame.pts - in_pts; + timeline.snap_by(snap_frame.pts - in_pts); snapped = true; break; } @@ -406,7 +478,7 @@ void Player::play_playlist_once() 1.0 / 5.0, 2.0 / 5.0, 3.0 / 5.0, 4.0 / 5.0 }) { double subsnap_pts = frame_lower.pts + fraction * (frame_upper.pts - frame_lower.pts); if (fabs(subsnap_pts - in_pts) < pts_snap_tolerance) { - in_pts_origin += lrint(subsnap_pts) - in_pts; + timeline.snap_by(lrint(subsnap_pts) - in_pts); in_pts = lrint(subsnap_pts); break; } @@ -444,8 +516,7 @@ void Player::play_playlist_once() // Start the next clip from the point where the fade went out. if (next_clip != nullptr) { - origin = next_frame_start; - in_pts_origin = next_clip->pts_in + lrint(next_clip_fade_time * TIMEBASE * clip->speed); + timeline.new_clip(next_frame_start, next_clip, /*pts_start_offset=*/lrint(next_clip_fade_time * TIMEBASE * clip->speed)); } } -- 2.39.2