4 // The actual video mixer, running in its own separate background thread.
15 #include <condition_variable>
26 #include <movit/image_format.h>
28 #include "audio_mixer.h"
29 #include "bmusb/bmusb.h"
32 #include "input_state.h"
34 #include "pbo_frame_allocator.h"
35 #include "ref_counted_frame.h"
36 #include "ref_counted_gl_sync.h"
39 #include "video_encoder.h"
40 #include "ycbcr_interpretation.h"
43 class ChromaSubsampler;
47 class TimecodeRenderer;
57 // For any card that's not the master (where we pick out the frames as they
58 // come, as fast as we can process), there's going to be a queue. The question
59 // is when we should drop frames from that queue (apart from the obvious
60 // dropping if the 16-frame queue should become full), especially given that
61 // the frame rate could be lower or higher than the master (either subtly or
62 // dramatically). We have two (conflicting) demands:
64 // 1. We want to avoid starving the queue.
65 // 2. We don't want to add more delay than is needed.
67 // Our general strategy is to drop as many frames as we can (helping for #2)
68 // that we think is safe for #1 given jitter. To this end, we set a lower floor N,
69 // where we assume that if we have N frames in the queue, we're always safe from
70 // starvation. (Typically, N will be 0 or 1. It starts off at 0.) If we have
71 // more than N frames in the queue after reading out the one we need, we head-drop
72 // them to reduce the queue.
74 // N is reduced as follows: If the queue has had at least one spare frame for
75 // at least 50 (master) frames (ie., it's been too conservative for a second),
76 // we reduce N by 1 and reset the timers.
78 // Whenever the queue is starved (we needed a frame but there was none),
79 // and we've been at N since the last starvation, N was obviously too low,
80 // so we increment it. We will never set N above 5, though.
81 class QueueLengthPolicy {
83 QueueLengthPolicy() {}
84 void reset(unsigned card_index) {
85 this->card_index = card_index;
86 safe_queue_length = 1;
87 frames_with_at_least_one = 0;
88 been_at_safe_point_since_last_starvation = false;
91 void register_metrics(const std::vector<std::pair<std::string, std::string>> &labels);
93 void update_policy(unsigned queue_length); // Call before picking out a frame, so 0 means starvation.
94 unsigned get_safe_queue_length() const { return safe_queue_length; }
97 unsigned card_index; // For debugging only.
98 unsigned safe_queue_length = 1; // Called N in the comments. Can never go below 1.
99 unsigned frames_with_at_least_one = 0;
100 bool been_at_safe_point_since_last_starvation = false;
103 std::atomic<int64_t> metric_input_queue_length_frames{0};
104 std::atomic<int64_t> metric_input_queue_safe_length_frames{1};
105 std::atomic<int64_t> metric_input_duped_frames{0};
110 // The surface format is used for offscreen destinations for OpenGL contexts we need.
111 Mixer(const QSurfaceFormat &format, unsigned num_cards);
116 void transition_clicked(int transition_num);
117 void channel_clicked(int preview_num);
122 OUTPUT_INPUT0, // 1, 2, 3, up to 15 follow numerically.
126 struct DisplayFrame {
127 // The chain for rendering this frame. To render a display frame,
128 // first wait for <ready_fence>, then call <setup_chain>
129 // to wire up all the inputs, and then finally call
130 // chain->render_to_screen() or similar.
131 movit::EffectChain *chain;
132 std::function<void()> setup_chain;
134 // Asserted when all the inputs are ready; you cannot render the chain
136 RefCountedGLsync ready_fence;
138 // Holds on to all the input frames needed for this display frame,
139 // so they are not released while still rendering.
140 std::vector<RefCountedFrame> input_frames;
142 // Textures that should be released back to the resource pool
143 // when this frame disappears, if any.
144 // TODO: Refcount these as well?
145 std::vector<GLuint> temp_textures;
147 // Implicitly frees the previous one if there's a new frame available.
148 bool get_display_frame(Output output, DisplayFrame *frame) {
149 return output_channel[output].get_display_frame(frame);
152 // NOTE: Callbacks will be called with a mutex held, so you should probably
153 // not do real work in them.
154 typedef std::function<void()> new_frame_ready_callback_t;
155 void add_frame_ready_callback(Output output, void *key, new_frame_ready_callback_t callback)
157 output_channel[output].add_frame_ready_callback(key, callback);
160 void remove_frame_ready_callback(Output output, void *key)
162 output_channel[output].remove_frame_ready_callback(key);
165 // TODO: Should this really be per-channel? Shouldn't it just be called for e.g. the live output?
166 typedef std::function<void(const std::vector<std::string> &)> transition_names_updated_callback_t;
167 void set_transition_names_updated_callback(Output output, transition_names_updated_callback_t callback)
169 output_channel[output].set_transition_names_updated_callback(callback);
172 typedef std::function<void(const std::string &)> name_updated_callback_t;
173 void set_name_updated_callback(Output output, name_updated_callback_t callback)
175 output_channel[output].set_name_updated_callback(callback);
178 typedef std::function<void(const std::string &)> color_updated_callback_t;
179 void set_color_updated_callback(Output output, color_updated_callback_t callback)
181 output_channel[output].set_color_updated_callback(callback);
184 std::vector<std::string> get_transition_names()
186 return theme->get_transition_names(pts());
189 unsigned get_num_channels() const
191 return theme->get_num_channels();
194 std::string get_channel_name(unsigned channel) const
196 return theme->get_channel_name(channel);
199 std::string get_channel_color(unsigned channel) const
201 return theme->get_channel_color(channel);
204 int get_channel_signal(unsigned channel) const
206 return theme->get_channel_signal(channel);
209 int map_signal(unsigned channel)
211 return theme->map_signal(channel);
214 unsigned get_master_clock() const
216 return master_clock_channel;
219 void set_master_clock(unsigned channel)
221 master_clock_channel = channel;
224 void set_signal_mapping(int signal, int card)
226 return theme->set_signal_mapping(signal, card);
229 YCbCrInterpretation get_input_ycbcr_interpretation(unsigned card_index) const;
230 void set_input_ycbcr_interpretation(unsigned card_index, const YCbCrInterpretation &interpretation);
232 bool get_supports_set_wb(unsigned channel) const
234 return theme->get_supports_set_wb(channel);
237 void set_wb(unsigned channel, double r, double g, double b) const
239 theme->set_wb(channel, r, g, b);
242 // Note: You can also get this through the global variable global_audio_mixer.
243 AudioMixer *get_audio_mixer() { return &audio_mixer; }
244 const AudioMixer *get_audio_mixer() const { return &audio_mixer; }
251 unsigned get_num_cards() const { return num_cards; }
253 std::string get_card_description(unsigned card_index) const {
254 assert(card_index < num_cards);
255 return cards[card_index].capture->get_description();
258 // The difference between this and the previous function is that if a card
259 // is used as the current output, get_card_description() will return the
260 // fake card that's replacing it for input, whereas this function will return
261 // the card's actual name.
262 std::string get_output_card_description(unsigned card_index) const {
263 assert(card_can_be_used_as_output(card_index));
264 assert(card_index < num_cards);
265 if (cards[card_index].parked_capture) {
266 return cards[card_index].parked_capture->get_description();
268 return cards[card_index].capture->get_description();
272 bool card_can_be_used_as_output(unsigned card_index) const {
273 assert(card_index < num_cards);
274 return cards[card_index].output != nullptr;
277 std::map<uint32_t, bmusb::VideoMode> get_available_video_modes(unsigned card_index) const {
278 assert(card_index < num_cards);
279 return cards[card_index].capture->get_available_video_modes();
282 uint32_t get_current_video_mode(unsigned card_index) const {
283 assert(card_index < num_cards);
284 return cards[card_index].capture->get_current_video_mode();
287 void set_video_mode(unsigned card_index, uint32_t mode) {
288 assert(card_index < num_cards);
289 cards[card_index].capture->set_video_mode(mode);
292 void start_mode_scanning(unsigned card_index);
294 std::map<uint32_t, std::string> get_available_video_inputs(unsigned card_index) const {
295 assert(card_index < num_cards);
296 return cards[card_index].capture->get_available_video_inputs();
299 uint32_t get_current_video_input(unsigned card_index) const {
300 assert(card_index < num_cards);
301 return cards[card_index].capture->get_current_video_input();
304 void set_video_input(unsigned card_index, uint32_t input) {
305 assert(card_index < num_cards);
306 cards[card_index].capture->set_video_input(input);
309 std::map<uint32_t, std::string> get_available_audio_inputs(unsigned card_index) const {
310 assert(card_index < num_cards);
311 return cards[card_index].capture->get_available_audio_inputs();
314 uint32_t get_current_audio_input(unsigned card_index) const {
315 assert(card_index < num_cards);
316 return cards[card_index].capture->get_current_audio_input();
319 void set_audio_input(unsigned card_index, uint32_t input) {
320 assert(card_index < num_cards);
321 cards[card_index].capture->set_audio_input(input);
324 void change_x264_bitrate(unsigned rate_kbit) {
325 video_encoder->change_x264_bitrate(rate_kbit);
328 int get_output_card_index() const { // -1 = no output, just stream.
329 return desired_output_card_index;
332 void set_output_card(int card_index) { // -1 = no output, just stream.
333 desired_output_card_index = card_index;
336 std::map<uint32_t, bmusb::VideoMode> get_available_output_video_modes() const;
338 uint32_t get_output_video_mode() const {
339 return desired_output_video_mode;
342 void set_output_video_mode(uint32_t mode) {
343 desired_output_video_mode = mode;
346 void set_display_timecode_in_stream(bool enable) {
347 display_timecode_in_stream = enable;
350 void set_display_timecode_on_stdout(bool enable) {
351 display_timecode_on_stdout = enable;
357 enum class CardType {
362 void configure_card(unsigned card_index, bmusb::CaptureInterface *capture, CardType card_type, DeckLinkOutput *output);
363 void set_output_card_internal(int card_index); // Should only be called from the mixer thread.
364 void bm_frame(unsigned card_index, uint16_t timecode,
365 bmusb::FrameAllocator::Frame video_frame, size_t video_offset, bmusb::VideoFormat video_format,
366 bmusb::FrameAllocator::Frame audio_frame, size_t audio_offset, bmusb::AudioFormat audio_format);
367 void bm_hotplug_add(libusb_device *dev);
368 void bm_hotplug_remove(unsigned card_index);
369 void place_rectangle(movit::Effect *resample_effect, movit::Effect *padding_effect, float x0, float y0, float x1, float y1);
371 void handle_hotplugged_cards();
372 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);
373 std::string get_timecode_text() const;
374 void render_one_frame(int64_t duration);
375 void audio_thread_func();
376 void release_display_frame(DisplayFrame *frame);
377 double pts() { return double(pts_int) / TIMEBASE; }
378 // Call this _before_ trying to pull out a frame from a capture card;
379 // it will update the policy and drop the right amount of frames for you.
380 void trim_queue(CaptureCard *card, unsigned card_index);
383 unsigned num_cards, num_video_inputs;
385 QSurface *mixer_surface, *h264_encoder_surface, *decklink_output_surface;
386 std::unique_ptr<movit::ResourcePool> resource_pool;
387 std::unique_ptr<Theme> theme;
388 std::atomic<unsigned> audio_source_channel{0};
389 std::atomic<int> master_clock_channel{0}; // Gets overridden by <output_card_index> if set.
390 int output_card_index = -1; // -1 for none.
391 uint32_t output_video_mode = -1;
393 // The mechanics of changing the output card and modes are so intricately connected
394 // with the work the mixer thread is doing. Thus, we don't change it directly,
395 // we just set this variable instead, which signals to the mixer thread that
396 // it should do the change before the next frame. This simplifies locking
397 // considerations immensely.
398 std::atomic<int> desired_output_card_index{-1};
399 std::atomic<uint32_t> desired_output_video_mode{0};
401 std::unique_ptr<movit::EffectChain> display_chain;
402 std::unique_ptr<ChromaSubsampler> chroma_subsampler;
403 std::unique_ptr<v210Converter> v210_converter;
404 std::unique_ptr<VideoEncoder> video_encoder;
406 std::unique_ptr<TimecodeRenderer> timecode_renderer;
407 std::atomic<bool> display_timecode_in_stream{false};
408 std::atomic<bool> display_timecode_on_stdout{false};
410 // Effects part of <display_chain>. Owned by <display_chain>.
411 movit::YCbCrInput *display_input;
413 int64_t pts_int = 0; // In TIMEBASE units.
414 unsigned frame_num = 0;
416 // Accumulated errors in number of 1/TIMEBASE audio samples. If OUTPUT_FREQUENCY divided by
417 // frame rate is integer, will always stay zero.
418 unsigned fractional_samples = 0;
420 mutable std::mutex card_mutex;
421 bool has_bmusb_thread = false;
423 std::unique_ptr<bmusb::CaptureInterface> capture;
424 bool is_fake_capture;
426 std::unique_ptr<DeckLinkOutput> output;
428 // If this card is used for output (ie., output_card_index points to it),
429 // it cannot simultaneously be uesd for capture, so <capture> gets replaced
430 // by a FakeCapture. However, since reconstructing the real capture object
431 // with all its state can be annoying, it is not being deleted, just stopped
433 std::unique_ptr<bmusb::CaptureInterface> parked_capture;
435 std::unique_ptr<PBOFrameAllocator> frame_allocator;
437 // Stuff for the OpenGL context (for texture uploading).
438 QSurface *surface = nullptr;
441 RefCountedFrame frame;
442 int64_t length; // In TIMEBASE units.
444 unsigned field; // Which field (0 or 1) of the frame to use. Always 0 for progressive.
445 std::function<void()> upload_func; // Needs to be called to actually upload the texture to OpenGL.
446 unsigned dropped_frames = 0; // Number of dropped frames before this one.
447 std::chrono::steady_clock::time_point received_timestamp = std::chrono::steady_clock::time_point::min();
449 std::deque<NewFrame> new_frames;
450 bool should_quit = false;
451 std::condition_variable new_frames_changed; // Set whenever new_frames (or should_quit) is changed.
453 QueueLengthPolicy queue_length_policy; // Refers to the "new_frames" queue.
455 int last_timecode = -1; // Unwrapped.
458 std::atomic<int64_t> metric_input_dropped_frames_jitter{0};
459 std::atomic<int64_t> metric_input_dropped_frames_error{0};
460 std::atomic<int64_t> metric_input_resets{0};
462 std::atomic<int64_t> metric_input_has_signal_bool{-1};
463 std::atomic<int64_t> metric_input_is_connected_bool{-1};
464 std::atomic<int64_t> metric_input_interlaced_bool{-1};
465 std::atomic<int64_t> metric_input_width_pixels{-1};
466 std::atomic<int64_t> metric_input_height_pixels{-1};
467 std::atomic<int64_t> metric_input_frame_rate_nom{-1};
468 std::atomic<int64_t> metric_input_frame_rate_den{-1};
469 std::atomic<int64_t> metric_input_sample_rate_hz{-1};
471 CaptureCard cards[MAX_VIDEO_CARDS]; // Protected by <card_mutex>.
472 YCbCrInterpretation ycbcr_interpretation[MAX_VIDEO_CARDS]; // Protected by <card_mutex>.
473 AudioMixer audio_mixer; // Same as global_audio_mixer (see audio_mixer.h).
474 bool input_card_is_master_clock(unsigned card_index, unsigned master_card_index) const;
475 struct OutputFrameInfo {
476 int dropped_frames; // Since last frame.
477 int num_samples; // Audio samples needed for this output frame.
478 int64_t frame_duration; // In TIMEBASE units.
480 std::chrono::steady_clock::time_point frame_timestamp;
482 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]);
484 InputState input_state;
486 // Cards we have been noticed about being hotplugged, but haven't tried adding yet.
487 // Protected by its own mutex.
488 std::mutex hotplug_mutex;
489 std::vector<libusb_device *> hotplugged_cards;
491 class OutputChannel {
494 void output_frame(DisplayFrame frame);
495 bool get_display_frame(DisplayFrame *frame);
496 void add_frame_ready_callback(void *key, new_frame_ready_callback_t callback);
497 void remove_frame_ready_callback(void *key);
498 void set_transition_names_updated_callback(transition_names_updated_callback_t callback);
499 void set_name_updated_callback(name_updated_callback_t callback);
500 void set_color_updated_callback(color_updated_callback_t callback);
506 Mixer *parent = nullptr; // Not owned.
507 std::mutex frame_mutex;
508 DisplayFrame current_frame, ready_frame; // protected by <frame_mutex>
509 bool has_current_frame = false, has_ready_frame = false; // protected by <frame_mutex>
510 std::map<void *, new_frame_ready_callback_t> new_frame_ready_callbacks; // protected by <frame_mutex>
511 transition_names_updated_callback_t transition_names_updated_callback;
512 name_updated_callback_t name_updated_callback;
513 color_updated_callback_t color_updated_callback;
515 std::vector<std::string> last_transition_names;
516 std::string last_name, last_color;
518 OutputChannel output_channel[NUM_OUTPUTS];
520 std::thread mixer_thread;
521 std::thread audio_thread;
522 std::atomic<bool> should_quit{false};
523 std::atomic<bool> should_cut{false};
525 std::unique_ptr<ALSAOutput> alsa;
531 std::chrono::steady_clock::time_point frame_timestamp;
533 std::mutex audio_mutex;
534 std::condition_variable audio_task_queue_changed;
535 std::queue<AudioTask> audio_task_queue; // Under audio_mutex.
537 // For mode scanning.
538 bool is_mode_scanning[MAX_VIDEO_CARDS]{ false };
539 std::vector<uint32_t> mode_scanlist[MAX_VIDEO_CARDS];
540 unsigned mode_scanlist_index[MAX_VIDEO_CARDS]{ 0 };
541 std::chrono::steady_clock::time_point last_mode_scan_change[MAX_VIDEO_CARDS];
544 std::atomic<int64_t> metric_frames_output_total{0};
545 std::atomic<int64_t> metric_frames_output_dropped{0};
546 std::atomic<double> metric_uptime_seconds{0.0};
547 std::atomic<int64_t> metrics_memory_used_bytes{0};
548 std::atomic<double> metrics_memory_locked_limit_bytes{0.0 / 0.0};
551 extern Mixer *global_mixer;
552 extern bool uses_mlock;
554 #endif // !defined(_MIXER_H)