Factor out some common logic from Player::thread_func().

[nageru] / futatabi / player.cpp

#include "player.h"

#include "clip_list.h"
#include "shared/context.h"
#include "defs.h"
#include "shared/ffmpeg_raii.h"
#include "flags.h"
#include "frame_on_disk.h"
#include "shared/httpd.h"
#include "jpeg_frame_view.h"
#include "shared/metrics.h"
#include "shared/mux.h"
#include "shared/timebase.h"
#include "video_stream.h"

#include <algorithm>
#include <chrono>
#include <condition_variable>
#include <movit/util.h>
#include <mutex>
#include <stdio.h>
#include <thread>
#include <vector>

using namespace std;
using namespace std::chrono;

extern HTTPD *global_httpd;

void Player::thread_func(AVFormatContext *file_avctx)
{
        pthread_setname_np(pthread_self(), "Player");

        QSurface *surface = create_surface();
        QOpenGLContext *context = create_context(surface);
        if (!make_current(context, surface)) {
                printf("oops\n");
                exit(1);
        }

        check_error();

        // Create the VideoStream object, now that we have an OpenGL context.
        if (stream_output != NO_STREAM_OUTPUT) {
                video_stream.reset(new VideoStream(file_avctx));
                video_stream->start();
        }

        check_error();

        while (!should_quit) {
                play_playlist_once();
        }
}

void Player::play_playlist_once()
{
        vector<Clip> clip_list;
        bool clip_ready;
        steady_clock::time_point before_sleep = steady_clock::now();

        // Wait until we're supposed to play something.
        {
                unique_lock<mutex> lock(queue_state_mu);
                playing = false;
                clip_ready = new_clip_changed.wait_for(lock, milliseconds(100), [this] {
                        return should_quit || new_clip_ready;
                });
                if (should_quit) {
                        return;
                }
                if (clip_ready) {
                        new_clip_ready = false;
                        playing = true;
                        clip_list = move(queued_clip_list);
                        queued_clip_list.clear();
                        assert(!clip_list.empty());
                }
        }

        steady_clock::duration time_slept = steady_clock::now() - before_sleep;
        pts += duration_cast<duration<size_t, TimebaseRatio>>(time_slept).count();

        if (!clip_ready) {
                if (video_stream != nullptr) {
                        ++metric_refresh_frame;
                        video_stream->schedule_refresh_frame(steady_clock::now(), pts, /*display_func=*/nullptr, QueueSpotHolder());
                }
                return;
        }

        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].pts_in;
        for (size_t clip_idx = 0; clip_idx < clip_list.size(); ++clip_idx) {
                const Clip &clip = clip_list[clip_idx];
                const Clip *next_clip = (clip_idx + 1 < clip_list.size()) ? &clip_list[clip_idx + 1] : 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_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);
                }

                int stream_idx = clip.stream_idx;

                // Start playing exactly at a frame.
                // TODO: Snap secondary (fade-to) clips in the same fashion
                // so that we don't get jank here).
                {
                        lock_guard<mutex> 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);
                        if (it != frames[stream_idx].end()) {
                                in_pts_origin = it->pts;
                        }
                }

                steady_clock::time_point next_frame_start;
                for (int 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 / global_flags.output_framerate);
                        pts = lrint(out_pts);

                        if (in_pts >= clip.pts_out) {
                                break;
                        }

                        steady_clock::duration time_behind = steady_clock::now() - next_frame_start;
                        if (stream_output != FILE_STREAM_OUTPUT && time_behind >= milliseconds(200)) {
                                fprintf(stderr, "WARNING: %ld ms behind, dropping a frame (no matter the type).\n",
                                        lrint(1e3 * duration<double>(time_behind).count()));
                                ++metric_dropped_unconditional_frame;
                                continue;
                        }


                        // pts not affected by the swapping below.
                        int64_t in_pts_for_progress = in_pts, in_pts_secondary_for_progress = -1;

                        int primary_stream_idx = stream_idx;
                        FrameOnDisk secondary_frame;
                        int secondary_stream_idx = -1;
                        float fade_alpha = 0.0f;
                        double time_left_this_clip = double(clip.pts_out - in_pts) / TIMEBASE / clip.speed;
                        if (next_clip != nullptr && time_left_this_clip <= next_clip_fade_time) {
                                // We're in a fade to the next clip.
                                secondary_stream_idx = next_clip->stream_idx;
                                int64_t in_pts_secondary = lrint(next_clip->pts_in + (next_clip_fade_time - time_left_this_clip) * TIMEBASE * clip.speed);
                                in_pts_secondary_for_progress = in_pts_secondary;
                                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);
                                        swap(in_pts, in_pts_secondary);
                                        fade_alpha = 1.0f - fade_alpha;
                                }

                                FrameOnDisk frame_lower, frame_upper;
                                bool ok = find_surrounding_frames(in_pts_secondary, secondary_stream_idx, &frame_lower, &frame_upper);
                                if (ok) {
                                        secondary_frame = frame_lower;
                                }
                        }

                        if (progress_callback != nullptr) {
                                // NOTE: None of this will take into account any snapping done below.
                                double played_this_clip = double(in_pts_for_progress - clip.pts_in) / TIMEBASE / clip.speed;
                                double total_length = double(clip.pts_out - clip.pts_in) / TIMEBASE / clip.speed;
                                map<size_t, double> progress{{ clip_idx, played_this_clip / total_length }};

                                if (next_clip != nullptr && time_left_this_clip <= next_clip_fade_time) {
                                        double played_next_clip = double(in_pts_secondary_for_progress - next_clip->pts_in) / TIMEBASE / next_clip->speed;
                                        double total_next_length = double(next_clip->pts_out - next_clip->pts_in) / TIMEBASE / next_clip->speed;
                                        progress[clip_idx + 1] = played_next_clip / total_next_length;
                                }
                                progress_callback(progress);
                        }

                        FrameOnDisk frame_lower, frame_upper;
                        bool ok = find_surrounding_frames(in_pts, primary_stream_idx, &frame_lower, &frame_upper);
                        if (!ok) {
                                break;
                        }

                        // Wait until we should, or (given buffering) can, output the frame.
                        {
                                unique_lock<mutex> lock(queue_state_mu);
                                if (video_stream == nullptr) {
                                        // No queue, just wait until the right time and then show the frame.
                                        new_clip_changed.wait_until(lock, next_frame_start, [this]{
                                                return should_quit || new_clip_ready || override_stream_idx != -1;
                                        });
                                        if (should_quit) {
                                                return;
                                        }
                                } else {
                                        // If the queue is full (which is really the state we'd like to be in),
                                        // wait until there's room for one more frame (ie., one was output from
                                        // VideoStream), or until or until there's a new clip we're supposed to play.
                                        //
                                        // In this case, we don't sleep until next_frame_start; the displaying is
                                        // done by the queue.
                                        new_clip_changed.wait(lock, [this]{
                                                if (num_queued_frames < max_queued_frames) {
                                                        return true;
                                                }
                                                return should_quit || new_clip_ready || override_stream_idx != -1;
                                        });
                                }
                                if (should_quit) {
                                        return;
                                }
                                if (new_clip_ready) {
                                        if (video_stream != nullptr) {
                                                lock.unlock();  // Urg.
                                                video_stream->clear_queue();
                                                lock.lock();
                                        }
                                        return;
                                }
                                // Honor if we got an override request for the camera.
                                if (override_stream_idx != -1) {
                                        stream_idx = override_stream_idx;
                                        override_stream_idx = -1;
                                        continue;
                                }
                        }

                        if (frame_lower.pts == frame_upper.pts || global_flags.interpolation_quality == 0) {
                                display_single_frame(primary_stream_idx, frame_lower, secondary_stream_idx,
                                                     secondary_frame, fade_alpha, next_frame_start, /*snapped=*/false);
                                continue;
                        }

                        // Snap to input frame: If we can do so with less than 1% jitter
                        // (ie., move less than 1% of an _output_ frame), do so.
                        // TODO: Snap secondary (fade-to) clips in the same fashion.
                        double pts_snap_tolerance = 0.01 * double(TIMEBASE) / global_flags.output_framerate;
                        bool snapped = false;
                        for (FrameOnDisk snap_frame : { frame_lower, frame_upper }) {
                                if (fabs(snap_frame.pts - in_pts) < pts_snap_tolerance) {
                                        display_single_frame(primary_stream_idx, snap_frame, secondary_stream_idx,
                                                             secondary_frame, fade_alpha, next_frame_start, /*snapped=*/true);
                                        in_pts_origin += snap_frame.pts - in_pts;
                                        snapped = true;
                                        break;
                                }
                        }
                        if (snapped) {
                                continue;
                        }

                        // The snapping above makes us lock to the input framerate, even in the presence
                        // of pts drift, for most typical cases where it's needed, like converting 60 → 2x60
                        // or 60 → 2x59.94. However, there are some corner cases like 25 → 2x59.94, where we'd
                        // get a snap very rarely (in the given case, once every 24 output frames), and by
                        // that time, we'd have drifted out. We could have solved this by changing the overall
                        // speed ever so slightly, but it requires that we know the actual frame rate (which
                        // is difficult in the presence of jitter and missed frames), or at least do some kind
                        // of matching/clustering. Instead, we take the opportunity to lock to in-between rational
                        // points if we can. E.g., if we are converting 60 → 2x60, we would not only snap to
                        // an original frame every other frame; we would also snap to exactly alpha=0.5 every
                        // in-between frame. Of course, we will still need to interpolate, but we get a lot
                        // closer when we actually get close to an original frame. In other words: Snap more
                        // often, but snap less each time. Unless the input and output frame rates are completely
                        // decorrelated with no common factor, of course (e.g. 12.345 → 34.567, which we should
                        // really never see in practice).
                        for (double fraction : { 1.0 / 2.0, 1.0 / 3.0, 2.0 / 3.0, 1.0 / 4.0, 3.0 / 4.0,
                                                 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;
                                        in_pts = lrint(subsnap_pts);
                                        break;
                                }
                        }

                        if (stream_output != FILE_STREAM_OUTPUT && time_behind >= milliseconds(100)) {
                                fprintf(stderr, "WARNING: %ld ms behind, dropping an interpolated frame.\n",
                                        lrint(1e3 * duration<double>(time_behind).count()));
                                ++metric_dropped_interpolated_frame;
                                continue;
                        }

                        double alpha = double(in_pts - frame_lower.pts) / (frame_upper.pts - frame_lower.pts);

                        if (video_stream == nullptr) {
                                // Previews don't do any interpolation.
                                assert(secondary_stream_idx == -1);
                                if (destination != nullptr) {
                                        destination->setFrame(primary_stream_idx, frame_lower);
                                }
                                last_pts_played = frame_lower.pts;
                        } else {
                                auto display_func = [this](shared_ptr<Frame> frame) {
                                        if (destination != nullptr) {
                                                destination->setFrame(frame);
                                        }
                                };
                                if (secondary_stream_idx == -1) {
                                        ++metric_interpolated_frame;
                                } else {
                                        ++metric_interpolated_faded_frame;
                                }
                                video_stream->schedule_interpolated_frame(
                                        next_frame_start, pts, display_func, QueueSpotHolder(this),
                                        frame_lower, frame_upper, alpha,
                                        secondary_frame, fade_alpha);
                                last_pts_played = in_pts;  // Not really needed; only previews use last_pts_played.
                        }
                }

                // The clip ended.
                if (should_quit) {
                        return;
                }
                if (done_callback != nullptr) {
                        done_callback();
                }

                // 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);
                }
        }

        if (done_callback != nullptr) {
                done_callback();
        }
}

void Player::display_single_frame(int primary_stream_idx, const FrameOnDisk &primary_frame, int secondary_stream_idx, const FrameOnDisk &secondary_frame, double fade_alpha, steady_clock::time_point frame_start, bool snapped)
{
                auto display_func = [this, primary_stream_idx, primary_frame, secondary_frame, fade_alpha]{
                if (destination != nullptr) {
                        destination->setFrame(primary_stream_idx, primary_frame, secondary_frame, fade_alpha);
                }
        };
        if (video_stream == nullptr) {
                display_func();
        } else {
                if (secondary_stream_idx == -1) {
                        if (snapped) {
                                ++metric_original_snapped_frame;
                        } else {
                                ++metric_original_frame;
                        }
                        video_stream->schedule_original_frame(
                                frame_start, pts, display_func, QueueSpotHolder(this),
                                primary_frame);
                } else {
                        assert(secondary_frame.pts != -1);
                        if (snapped) {
                                ++metric_faded_snapped_frame;
                        } else {
                                ++metric_faded_frame;
                        }
                        video_stream->schedule_faded_frame(frame_start, pts, display_func,
                                QueueSpotHolder(this), primary_frame,
                                secondary_frame, fade_alpha);
                }
        }
        last_pts_played = primary_frame.pts;
}

// Find the frame immediately before and after this point.
bool Player::find_surrounding_frames(int64_t pts, int stream_idx, FrameOnDisk *frame_lower, FrameOnDisk *frame_upper)
{
        lock_guard<mutex> lock(frame_mu);

        // Find the first frame such that frame.pts >= pts.
        auto it = find_last_frame_before(frames[stream_idx], pts);
        if (it == frames[stream_idx].end()) {
                return false;
        }
        *frame_upper = *it;

        // Find the last frame such that in_pts <= frame.pts (if any).
        if (it == frames[stream_idx].begin()) {
                *frame_lower = *it;
        } else {
                *frame_lower = *(it - 1);
        }
        assert(pts >= frame_lower->pts);
        assert(pts <= frame_upper->pts);
        return true;
}

Player::Player(JPEGFrameView *destination, Player::StreamOutput stream_output, AVFormatContext *file_avctx)
        : destination(destination), stream_output(stream_output)
{
        player_thread = thread(&Player::thread_func, this, file_avctx);

        if (stream_output == HTTPD_STREAM_OUTPUT) {
                global_metrics.add("http_output_frames", {{ "type", "original" }, { "reason", "edge_frame_or_no_interpolation" }}, &metric_original_frame);
                global_metrics.add("http_output_frames", {{ "type", "faded" }, { "reason", "edge_frame_or_no_interpolation" }}, &metric_faded_frame);
                global_metrics.add("http_output_frames", {{ "type", "original" }, { "reason", "snapped" }}, &metric_original_snapped_frame);
                global_metrics.add("http_output_frames", {{ "type", "faded" }, { "reason", "snapped" }}, &metric_faded_snapped_frame);
                global_metrics.add("http_output_frames", {{ "type", "interpolated" }}, &metric_interpolated_frame);
                global_metrics.add("http_output_frames", {{ "type", "interpolated_faded" }}, &metric_interpolated_faded_frame);
                global_metrics.add("http_output_frames", {{ "type", "refresh" }}, &metric_refresh_frame);
                global_metrics.add("http_dropped_frames", {{ "type", "interpolated" }}, &metric_dropped_interpolated_frame);
                global_metrics.add("http_dropped_frames", {{ "type", "unconditional" }}, &metric_dropped_unconditional_frame);
        }
}

Player::~Player()
{
        should_quit = true;
        if (video_stream != nullptr) {
                video_stream->stop();
        }
        new_clip_changed.notify_all();
        player_thread.join();
}

void Player::play(const vector<Clip> &clips)
{
        lock_guard<mutex> lock(queue_state_mu);
        new_clip_ready = true;
        queued_clip_list = clips;
        override_stream_idx = -1;
        new_clip_changed.notify_all();
}

void Player::override_angle(unsigned stream_idx)
{
        int64_t last_pts;

        // Corner case: If a new clip is waiting to be played, change its stream and then we're done.
        {
                lock_guard<mutex> lock(queue_state_mu);
                if (new_clip_ready) {
                        assert(queued_clip_list.size() == 1);
                        queued_clip_list[0].stream_idx = stream_idx;
                        return;
                }

                // If we are playing a clip, set override_stream_idx, and the player thread will
                // pick it up and change its internal index.
                if (playing) {
                        override_stream_idx = stream_idx;
                        new_clip_changed.notify_all();
                        return;
                }

                // OK, so we're standing still, presumably at the end of a clip.
                // Look at the last frame played (if it exists), and show the closest
                // thing we've got.
                if (last_pts_played < 0) {
                        return;
                }
                last_pts = last_pts_played;
        }

        lock_guard<mutex> lock(frame_mu);
        auto it = find_first_frame_at_or_after(frames[stream_idx], last_pts);
        if (it == frames[stream_idx].end()) {
                return;
        }
        destination->setFrame(stream_idx, *it);
}

void Player::take_queue_spot()
{
        lock_guard<mutex> lock(queue_state_mu);
        ++num_queued_frames;
}

void Player::release_queue_spot()
{
        lock_guard<mutex> lock(queue_state_mu);
        assert(num_queued_frames > 0);
        --num_queued_frames;
        new_clip_changed.notify_all();
}

double compute_time_left(const vector<Clip> &clips, const map<size_t, double> &progress)
{
        // Look at the last clip and then start counting from there.
        assert(!progress.empty());
        auto last_it = progress.end();
        --last_it;
        double remaining = 0.0;
        double last_fade_time_seconds = 0.0;
        for (size_t row = last_it->first; row < clips.size(); ++row) {
                const Clip &clip = clips[row];
                double clip_length = double(clip.pts_out - clip.pts_in) / TIMEBASE / clip.speed;
                if (row == last_it->first) {
                        // A clip we're playing: Subtract the part we've already played.
                        remaining = clip_length * (1.0 - last_it->second);
                } else {
                        // A clip we haven't played yet: Subtract the part that's overlapping
                        // with a previous clip (due to fade).
                        remaining += max(clip_length - last_fade_time_seconds, 0.0);
                }
                last_fade_time_seconds = min(clip_length, clip.fade_time_seconds);
        }
        return remaining;
}