+// For any card that's not the master (where we pick out the frames as they
+// come, as fast as we can process), there's going to be a queue. The question
+// is when we should drop frames from that queue (apart from the obvious
+// dropping if the 16-frame queue should become full), especially given that
+// the frame rate could be lower or higher than the master (either subtly or
+// dramatically). We have two (conflicting) demands:
+//
+// 1. We want to avoid starving the queue.
+// 2. We don't want to add more delay than is needed.
+//
+// Our general strategy is to drop as many frames as we can (helping for #2)
+// that we think is safe for #1 given jitter. To this end, we measure the
+// deviation from the expected arrival time for all cards, and use that for
+// continuous jitter estimation.
+//
+// We then drop everything from the queue that we're sure we won't need to
+// serve the output in the time before the next frame arrives. Typically,
+// this means the queue will contain 0 or 1 frames, although more is also
+// possible if the jitter is very high.
+class QueueLengthPolicy {
+public:
+ QueueLengthPolicy() {}
+ void reset(unsigned card_index) {
+ this->card_index = card_index;
+ }
+
+ void register_metrics(const std::vector<std::pair<std::string, std::string>> &labels);
+ void unregister_metrics(const std::vector<std::pair<std::string, std::string>> &labels);
+
+ // Call after picking out a frame, so 0 means starvation.
+ void update_policy(std::chrono::steady_clock::time_point now,
+ std::chrono::steady_clock::time_point expected_next_frame,
+ int64_t input_frame_duration,
+ int64_t master_frame_duration,
+ double max_input_card_jitter_seconds,
+ double max_master_card_jitter_seconds);
+ unsigned get_safe_queue_length() const { return safe_queue_length; }
+
+private:
+ unsigned card_index; // For debugging and metrics only.
+ unsigned safe_queue_length = 0; // Can never go below zero.
+
+ // Metrics.
+ std::atomic<int64_t> metric_input_queue_safe_length_frames{1};
+};
+
+class Mixer {
+public:
+ // The surface format is used for offscreen destinations for OpenGL contexts we need.
+ Mixer(const QSurfaceFormat &format, unsigned num_cards);
+ ~Mixer();
+ void start();
+ void quit();
+
+ void transition_clicked(int transition_num);
+ void channel_clicked(int preview_num);
+
+ enum Output {
+ OUTPUT_LIVE = 0,
+ OUTPUT_PREVIEW,
+ OUTPUT_INPUT0, // 1, 2, 3, up to 15 follow numerically.
+ NUM_OUTPUTS = 18
+ };
+
+ struct DisplayFrame {
+ // The chain for rendering this frame. To render a display frame,
+ // first wait for <ready_fence>, then call <setup_chain>
+ // to wire up all the inputs, and then finally call
+ // chain->render_to_screen() or similar.
+ movit::EffectChain *chain;
+ std::function<void()> setup_chain;
+
+ // Asserted when all the inputs are ready; you cannot render the chain
+ // before this.
+ RefCountedGLsync ready_fence;
+
+ // Holds on to all the input frames needed for this display frame,
+ // so they are not released while still rendering.
+ std::vector<RefCountedFrame> input_frames;
+
+ // Textures that should be released back to the resource pool
+ // when this frame disappears, if any.
+ // TODO: Refcount these as well?
+ std::vector<GLuint> temp_textures;
+ };
+ // Implicitly frees the previous one if there's a new frame available.
+ bool get_display_frame(Output output, DisplayFrame *frame) {
+ return output_channel[output].get_display_frame(frame);
+ }
+
+ // NOTE: Callbacks will be called with a mutex held, so you should probably
+ // not do real work in them.
+ typedef std::function<void()> new_frame_ready_callback_t;
+ void add_frame_ready_callback(Output output, void *key, new_frame_ready_callback_t callback)
+ {
+ output_channel[output].add_frame_ready_callback(key, callback);
+ }
+
+ void remove_frame_ready_callback(Output output, void *key)
+ {
+ output_channel[output].remove_frame_ready_callback(key);
+ }
+
+ // TODO: Should this really be per-channel? Shouldn't it just be called for e.g. the live output?
+ typedef std::function<void(const std::vector<std::string> &)> transition_names_updated_callback_t;
+ void set_transition_names_updated_callback(Output output, transition_names_updated_callback_t callback)
+ {
+ output_channel[output].set_transition_names_updated_callback(callback);
+ }
+
+ typedef std::function<void(const std::string &)> name_updated_callback_t;
+ void set_name_updated_callback(Output output, name_updated_callback_t callback)
+ {
+ output_channel[output].set_name_updated_callback(callback);
+ }
+
+ typedef std::function<void(const std::string &)> color_updated_callback_t;
+ void set_color_updated_callback(Output output, color_updated_callback_t callback)
+ {
+ output_channel[output].set_color_updated_callback(callback);
+ }
+
+ std::vector<std::string> get_transition_names()
+ {
+ return theme->get_transition_names(pts());
+ }
+
+ unsigned get_num_channels() const
+ {
+ return theme->get_num_channels();
+ }
+
+ std::string get_channel_name(unsigned channel) const
+ {
+ return theme->get_channel_name(channel);
+ }
+
+ std::string get_channel_color(unsigned channel) const
+ {
+ return theme->get_channel_color(channel);
+ }
+
+ int get_channel_signal(unsigned channel) const
+ {
+ return theme->get_channel_signal(channel);
+ }
+
+ int map_signal(unsigned channel)
+ {
+ return theme->map_signal(channel);
+ }
+
+ unsigned get_master_clock() const
+ {
+ return master_clock_channel;
+ }
+
+ void set_master_clock(unsigned channel)
+ {
+ master_clock_channel = channel;
+ }
+
+ void set_signal_mapping(int signal, int card)
+ {
+ return theme->set_signal_mapping(signal, card);
+ }
+
+ YCbCrInterpretation get_input_ycbcr_interpretation(unsigned card_index) const;
+ void set_input_ycbcr_interpretation(unsigned card_index, const YCbCrInterpretation &interpretation);
+
+ bool get_supports_set_wb(unsigned channel) const
+ {
+ return theme->get_supports_set_wb(channel);
+ }
+
+ void set_wb(unsigned channel, double r, double g, double b) const
+ {
+ theme->set_wb(channel, r, g, b);
+ }
+
+ // Note: You can also get this through the global variable global_audio_mixer.
+ AudioMixer *get_audio_mixer() { return &audio_mixer; }
+ const AudioMixer *get_audio_mixer() const { return &audio_mixer; }
+
+ void schedule_cut()
+ {
+ should_cut = true;
+ }
+
+ unsigned get_num_cards() const { return num_cards; }
+
+ std::string get_card_description(unsigned card_index) const {
+ assert(card_index < num_cards);
+ return cards[card_index].capture->get_description();
+ }
+
+ // The difference between this and the previous function is that if a card
+ // is used as the current output, get_card_description() will return the
+ // fake card that's replacing it for input, whereas this function will return
+ // the card's actual name.
+ std::string get_output_card_description(unsigned card_index) const {
+ assert(card_can_be_used_as_output(card_index));
+ assert(card_index < num_cards);
+ if (cards[card_index].parked_capture) {
+ return cards[card_index].parked_capture->get_description();
+ } else {
+ return cards[card_index].capture->get_description();
+ }
+ }
+
+ bool card_can_be_used_as_output(unsigned card_index) const {
+ assert(card_index < num_cards);
+ return cards[card_index].output != nullptr;
+ }
+
+ std::map<uint32_t, bmusb::VideoMode> get_available_video_modes(unsigned card_index) const {
+ assert(card_index < num_cards);
+ return cards[card_index].capture->get_available_video_modes();
+ }
+
+ uint32_t get_current_video_mode(unsigned card_index) const {
+ assert(card_index < num_cards);
+ return cards[card_index].capture->get_current_video_mode();
+ }
+
+ void set_video_mode(unsigned card_index, uint32_t mode) {
+ assert(card_index < num_cards);
+ cards[card_index].capture->set_video_mode(mode);
+ }
+
+ void start_mode_scanning(unsigned card_index);
+
+ std::map<uint32_t, std::string> get_available_video_inputs(unsigned card_index) const {
+ assert(card_index < num_cards);
+ return cards[card_index].capture->get_available_video_inputs();
+ }
+
+ uint32_t get_current_video_input(unsigned card_index) const {
+ assert(card_index < num_cards);
+ return cards[card_index].capture->get_current_video_input();
+ }
+
+ void set_video_input(unsigned card_index, uint32_t input) {
+ assert(card_index < num_cards);
+ cards[card_index].capture->set_video_input(input);
+ }
+
+ std::map<uint32_t, std::string> get_available_audio_inputs(unsigned card_index) const {
+ assert(card_index < num_cards);
+ return cards[card_index].capture->get_available_audio_inputs();
+ }
+
+ uint32_t get_current_audio_input(unsigned card_index) const {
+ assert(card_index < num_cards);
+ return cards[card_index].capture->get_current_audio_input();
+ }
+
+ void set_audio_input(unsigned card_index, uint32_t input) {
+ assert(card_index < num_cards);
+ cards[card_index].capture->set_audio_input(input);
+ }
+
+ void change_x264_bitrate(unsigned rate_kbit) {
+ video_encoder->change_x264_bitrate(rate_kbit);
+ }
+
+ int get_output_card_index() const { // -1 = no output, just stream.
+ return desired_output_card_index;
+ }
+
+ void set_output_card(int card_index) { // -1 = no output, just stream.
+ desired_output_card_index = card_index;
+ }
+
+ std::map<uint32_t, bmusb::VideoMode> get_available_output_video_modes() const;
+
+ uint32_t get_output_video_mode() const {
+ return desired_output_video_mode;
+ }
+
+ void set_output_video_mode(uint32_t mode) {
+ desired_output_video_mode = mode;
+ }
+
+ void set_display_timecode_in_stream(bool enable) {
+ display_timecode_in_stream = enable;
+ }
+
+ void set_display_timecode_on_stdout(bool enable) {
+ display_timecode_on_stdout = enable;
+ }
+
+ int64_t get_num_connected_clients() const {
+ return httpd.get_num_connected_clients();
+ }
+
+ std::vector<Theme::MenuEntry> get_theme_menu() { return theme->get_theme_menu(); }
+
+ void theme_menu_entry_clicked(int lua_ref) { return theme->theme_menu_entry_clicked(lua_ref); }
+
+ void set_theme_menu_callback(std::function<void()> callback)
+ {
+ theme->set_theme_menu_callback(callback);
+ }
+
+private:
+ struct CaptureCard;
+
+ enum class CardType {
+ LIVE_CARD,
+ FAKE_CAPTURE,
+ FFMPEG_INPUT,
+ CEF_INPUT,
+ };
+ void configure_card(unsigned card_index, bmusb::CaptureInterface *capture, CardType card_type, DeckLinkOutput *output);
+ void set_output_card_internal(int card_index); // Should only be called from the mixer thread.
+ void bm_frame(unsigned card_index, uint16_t timecode,
+ bmusb::FrameAllocator::Frame video_frame, size_t video_offset, bmusb::VideoFormat video_format,
+ bmusb::FrameAllocator::Frame audio_frame, size_t audio_offset, bmusb::AudioFormat audio_format);
+ void bm_hotplug_add(libusb_device *dev);
+ void bm_hotplug_remove(unsigned card_index);
+ void place_rectangle(movit::Effect *resample_effect, movit::Effect *padding_effect, float x0, float y0, float x1, float y1);
+ void thread_func();
+ void handle_hotplugged_cards();
+ void schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame, bool is_preroll, std::chrono::steady_clock::time_point frame_timestamp);
+ std::string get_timecode_text() const;
+ void render_one_frame(int64_t duration);
+ void audio_thread_func();
+ void release_display_frame(DisplayFrame *frame);
+ double pts() { return double(pts_int) / TIMEBASE; }
+ void trim_queue(CaptureCard *card, size_t safe_queue_length);
+ std::pair<std::string, std::string> get_channels_json();
+ std::pair<std::string, std::string> get_channel_color_http(unsigned channel_idx);
+
+ HTTPD httpd;
+ unsigned num_cards, num_video_inputs, num_html_inputs;
+
+ QSurface *mixer_surface, *h264_encoder_surface, *decklink_output_surface;
+ std::unique_ptr<movit::ResourcePool> resource_pool;
+ std::unique_ptr<Theme> theme;
+ std::atomic<unsigned> audio_source_channel{0};
+ std::atomic<int> master_clock_channel{0}; // Gets overridden by <output_card_index> if set.
+ int output_card_index = -1; // -1 for none.
+ uint32_t output_video_mode = -1;
+
+ // The mechanics of changing the output card and modes are so intricately connected
+ // with the work the mixer thread is doing. Thus, we don't change it directly,
+ // we just set this variable instead, which signals to the mixer thread that
+ // it should do the change before the next frame. This simplifies locking
+ // considerations immensely.
+ std::atomic<int> desired_output_card_index{-1};
+ std::atomic<uint32_t> desired_output_video_mode{0};
+
+ std::unique_ptr<movit::EffectChain> display_chain;
+ std::unique_ptr<ChromaSubsampler> chroma_subsampler;
+ std::unique_ptr<v210Converter> v210_converter;
+ std::unique_ptr<VideoEncoder> video_encoder;
+
+ std::unique_ptr<TimecodeRenderer> timecode_renderer;
+ std::atomic<bool> display_timecode_in_stream{false};
+ std::atomic<bool> display_timecode_on_stdout{false};
+
+ // Effects part of <display_chain>. Owned by <display_chain>.
+ movit::YCbCrInput *display_input;
+
+ int64_t pts_int = 0; // In TIMEBASE units.
+ unsigned frame_num = 0;
+
+ // Accumulated errors in number of 1/TIMEBASE audio samples. If OUTPUT_FREQUENCY divided by
+ // frame rate is integer, will always stay zero.
+ unsigned fractional_samples = 0;
+
+ mutable std::mutex card_mutex;
+ bool has_bmusb_thread = false;
+ struct CaptureCard {
+ std::unique_ptr<bmusb::CaptureInterface> capture;
+ bool is_fake_capture;
+ CardType type;
+ std::unique_ptr<DeckLinkOutput> output;
+
+ // CEF only delivers frames when it actually has a change.
+ // If we trim the queue for latency reasons, we could thus
+ // end up in a situation trimming a frame that was meant to
+ // be displayed for a long time, which is really suboptimal.
+ // Thus, if we drop the last frame we have, may_have_dropped_last_frame
+ // is set to true, and the next starvation event will trigger
+ // us requestin a CEF repaint.
+ bool is_cef_capture, may_have_dropped_last_frame = false;
+
+ // If this card is used for output (ie., output_card_index points to it),
+ // it cannot simultaneously be uesd for capture, so <capture> gets replaced
+ // by a FakeCapture. However, since reconstructing the real capture object
+ // with all its state can be annoying, it is not being deleted, just stopped
+ // and moved here.
+ std::unique_ptr<bmusb::CaptureInterface> parked_capture;
+
+ std::unique_ptr<PBOFrameAllocator> frame_allocator;
+
+ // Stuff for the OpenGL context (for texture uploading).
+ QSurface *surface = nullptr;
+
+ struct NewFrame {
+ RefCountedFrame frame;
+ int64_t length; // In TIMEBASE units.
+ bool interlaced;
+ unsigned field; // Which field (0 or 1) of the frame to use. Always 0 for progressive.
+ std::function<void()> upload_func; // Needs to be called to actually upload the texture to OpenGL.
+ unsigned dropped_frames = 0; // Number of dropped frames before this one.
+ std::chrono::steady_clock::time_point received_timestamp = std::chrono::steady_clock::time_point::min();
+ };
+ std::deque<NewFrame> new_frames;
+ bool should_quit = false;
+ std::condition_variable new_frames_changed; // Set whenever new_frames (or should_quit) is changed.
+
+ QueueLengthPolicy queue_length_policy; // Refers to the "new_frames" queue.
+
+ int last_timecode = -1; // Unwrapped.
+
+ JitterHistory jitter_history;
+
+ // Metrics.
+ std::vector<std::pair<std::string, std::string>> labels;
+ std::atomic<int64_t> metric_input_received_frames{0};
+ std::atomic<int64_t> metric_input_duped_frames{0};
+ std::atomic<int64_t> metric_input_dropped_frames_jitter{0};
+ std::atomic<int64_t> metric_input_dropped_frames_error{0};
+ std::atomic<int64_t> metric_input_resets{0};
+ std::atomic<int64_t> metric_input_queue_length_frames{0};
+
+ std::atomic<int64_t> metric_input_has_signal_bool{-1};
+ std::atomic<int64_t> metric_input_is_connected_bool{-1};
+ std::atomic<int64_t> metric_input_interlaced_bool{-1};
+ std::atomic<int64_t> metric_input_width_pixels{-1};
+ std::atomic<int64_t> metric_input_height_pixels{-1};
+ std::atomic<int64_t> metric_input_frame_rate_nom{-1};
+ std::atomic<int64_t> metric_input_frame_rate_den{-1};
+ std::atomic<int64_t> metric_input_sample_rate_hz{-1};
+ };
+ JitterHistory output_jitter_history;
+ CaptureCard cards[MAX_VIDEO_CARDS]; // Protected by <card_mutex>.
+ YCbCrInterpretation ycbcr_interpretation[MAX_VIDEO_CARDS]; // Protected by <card_mutex>.
+ AudioMixer audio_mixer; // Same as global_audio_mixer (see audio_mixer.h).
+ bool input_card_is_master_clock(unsigned card_index, unsigned master_card_index) const;
+ struct OutputFrameInfo {
+ int dropped_frames; // Since last frame.
+ int num_samples; // Audio samples needed for this output frame.
+ int64_t frame_duration; // In TIMEBASE units.
+ bool is_preroll;
+ std::chrono::steady_clock::time_point frame_timestamp;
+ };
+ OutputFrameInfo get_one_frame_from_each_card(unsigned master_card_index, bool master_card_is_output, CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS], bool has_new_frame[MAX_VIDEO_CARDS]);
+
+ InputState input_state;
+
+ // Cards we have been noticed about being hotplugged, but haven't tried adding yet.
+ // Protected by its own mutex.
+ std::mutex hotplug_mutex;
+ std::vector<libusb_device *> hotplugged_cards;
+
+ class OutputChannel {
+ public:
+ ~OutputChannel();
+ void output_frame(DisplayFrame &&frame);
+ bool get_display_frame(DisplayFrame *frame);
+ void add_frame_ready_callback(void *key, new_frame_ready_callback_t callback);
+ void remove_frame_ready_callback(void *key);
+ void set_transition_names_updated_callback(transition_names_updated_callback_t callback);
+ void set_name_updated_callback(name_updated_callback_t callback);
+ void set_color_updated_callback(color_updated_callback_t callback);
+
+ private:
+ friend class Mixer;
+
+ unsigned channel;
+ Mixer *parent = nullptr; // Not owned.
+ std::mutex frame_mutex;
+ DisplayFrame current_frame, ready_frame; // protected by <frame_mutex>
+ bool has_current_frame = false, has_ready_frame = false; // protected by <frame_mutex>
+ std::map<void *, new_frame_ready_callback_t> new_frame_ready_callbacks; // protected by <frame_mutex>
+ transition_names_updated_callback_t transition_names_updated_callback;
+ name_updated_callback_t name_updated_callback;
+ color_updated_callback_t color_updated_callback;
+
+ std::vector<std::string> last_transition_names;
+ std::string last_name, last_color;
+ };
+ OutputChannel output_channel[NUM_OUTPUTS];
+
+ std::thread mixer_thread;
+ std::thread audio_thread;
+ std::atomic<bool> should_quit{false};
+ std::atomic<bool> should_cut{false};
+
+ std::unique_ptr<ALSAOutput> alsa;
+
+ struct AudioTask {
+ int64_t pts_int;
+ int num_samples;
+ bool adjust_rate;
+ std::chrono::steady_clock::time_point frame_timestamp;
+ };
+ std::mutex audio_mutex;
+ std::condition_variable audio_task_queue_changed;
+ std::queue<AudioTask> audio_task_queue; // Under audio_mutex.
+
+ // For mode scanning.
+ bool is_mode_scanning[MAX_VIDEO_CARDS]{ false };
+ std::vector<uint32_t> mode_scanlist[MAX_VIDEO_CARDS];
+ unsigned mode_scanlist_index[MAX_VIDEO_CARDS]{ 0 };
+ std::chrono::steady_clock::time_point last_mode_scan_change[MAX_VIDEO_CARDS];