4 // The actual video mixer, running in its own separate background thread.
15 #include <condition_variable>
26 #include "audio_mixer.h"
27 #include "bmusb/bmusb.h"
30 #include "input_state.h"
32 #include "pbo_frame_allocator.h"
33 #include "ref_counted_frame.h"
34 #include "ref_counted_gl_sync.h"
37 #include "video_encoder.h"
40 class ChromaSubsampler;
51 // For any card that's not the master (where we pick out the frames as they
52 // come, as fast as we can process), there's going to be a queue. The question
53 // is when we should drop frames from that queue (apart from the obvious
54 // dropping if the 16-frame queue should become full), especially given that
55 // the frame rate could be lower or higher than the master (either subtly or
56 // dramatically). We have two (conflicting) demands:
58 // 1. We want to avoid starving the queue.
59 // 2. We don't want to add more delay than is needed.
61 // Our general strategy is to drop as many frames as we can (helping for #2)
62 // that we think is safe for #1 given jitter. To this end, we set a lower floor N,
63 // where we assume that if we have N frames in the queue, we're always safe from
64 // starvation. (Typically, N will be 0 or 1. It starts off at 0.) If we have
65 // more than N frames in the queue after reading out the one we need, we head-drop
66 // them to reduce the queue.
68 // N is reduced as follows: If the queue has had at least one spare frame for
69 // at least 50 (master) frames (ie., it's been too conservative for a second),
70 // we reduce N by 1 and reset the timers. TODO: Only do this if N ever actually
73 // Whenever the queue is starved (we needed a frame but there was none),
74 // and we've been at N since the last starvation, N was obviously too low,
75 // so we increment it. We will never set N above 5, though.
76 class QueueLengthPolicy {
78 QueueLengthPolicy() {}
79 void reset(unsigned card_index) {
80 this->card_index = card_index;
81 safe_queue_length = 0;
82 frames_with_at_least_one = 0;
83 been_at_safe_point_since_last_starvation = false;
86 void update_policy(int queue_length); // Give in -1 for starvation.
87 unsigned get_safe_queue_length() const { return safe_queue_length; }
90 unsigned card_index; // For debugging only.
91 unsigned safe_queue_length = 0; // Called N in the comments.
92 unsigned frames_with_at_least_one = 0;
93 bool been_at_safe_point_since_last_starvation = false;
98 // The surface format is used for offscreen destinations for OpenGL contexts we need.
99 Mixer(const QSurfaceFormat &format, unsigned num_cards);
104 void transition_clicked(int transition_num);
105 void channel_clicked(int preview_num);
110 OUTPUT_INPUT0, // 1, 2, 3, up to 15 follow numerically.
114 struct DisplayFrame {
115 // The chain for rendering this frame. To render a display frame,
116 // first wait for <ready_fence>, then call <setup_chain>
117 // to wire up all the inputs, and then finally call
118 // chain->render_to_screen() or similar.
119 movit::EffectChain *chain;
120 std::function<void()> setup_chain;
122 // Asserted when all the inputs are ready; you cannot render the chain
124 RefCountedGLsync ready_fence;
126 // Holds on to all the input frames needed for this display frame,
127 // so they are not released while still rendering.
128 std::vector<RefCountedFrame> input_frames;
130 // Textures that should be released back to the resource pool
131 // when this frame disappears, if any.
132 // TODO: Refcount these as well?
133 std::vector<GLuint> temp_textures;
135 // Implicitly frees the previous one if there's a new frame available.
136 bool get_display_frame(Output output, DisplayFrame *frame) {
137 return output_channel[output].get_display_frame(frame);
140 typedef std::function<void()> new_frame_ready_callback_t;
141 void set_frame_ready_callback(Output output, new_frame_ready_callback_t callback)
143 output_channel[output].set_frame_ready_callback(callback);
146 // TODO: Should this really be per-channel? Shouldn't it just be called for e.g. the live output?
147 typedef std::function<void(const std::vector<std::string> &)> transition_names_updated_callback_t;
148 void set_transition_names_updated_callback(Output output, transition_names_updated_callback_t callback)
150 output_channel[output].set_transition_names_updated_callback(callback);
153 typedef std::function<void(const std::string &)> name_updated_callback_t;
154 void set_name_updated_callback(Output output, name_updated_callback_t callback)
156 output_channel[output].set_name_updated_callback(callback);
159 typedef std::function<void(const std::string &)> color_updated_callback_t;
160 void set_color_updated_callback(Output output, color_updated_callback_t callback)
162 output_channel[output].set_color_updated_callback(callback);
165 std::vector<std::string> get_transition_names()
167 return theme->get_transition_names(pts());
170 unsigned get_num_channels() const
172 return theme->get_num_channels();
175 std::string get_channel_name(unsigned channel) const
177 return theme->get_channel_name(channel);
180 std::string get_channel_color(unsigned channel) const
182 return theme->get_channel_color(channel);
185 int get_channel_signal(unsigned channel) const
187 return theme->get_channel_signal(channel);
190 int map_signal(unsigned channel)
192 return theme->map_signal(channel);
195 unsigned get_master_clock() const
197 return master_clock_channel;
200 void set_master_clock(unsigned channel)
202 master_clock_channel = channel;
205 void set_signal_mapping(int signal, int card)
207 return theme->set_signal_mapping(signal, card);
210 bool get_supports_set_wb(unsigned channel) const
212 return theme->get_supports_set_wb(channel);
215 void set_wb(unsigned channel, double r, double g, double b) const
217 theme->set_wb(channel, r, g, b);
220 // Note: You can also get this through the global variable global_audio_mixer.
221 AudioMixer *get_audio_mixer() { return &audio_mixer; }
222 const AudioMixer *get_audio_mixer() const { return &audio_mixer; }
229 unsigned get_num_cards() const { return num_cards; }
231 std::string get_card_description(unsigned card_index) const {
232 assert(card_index < num_cards);
233 return cards[card_index].capture->get_description();
236 std::map<uint32_t, bmusb::VideoMode> get_available_video_modes(unsigned card_index) const {
237 assert(card_index < num_cards);
238 return cards[card_index].capture->get_available_video_modes();
241 uint32_t get_current_video_mode(unsigned card_index) const {
242 assert(card_index < num_cards);
243 return cards[card_index].capture->get_current_video_mode();
246 void set_video_mode(unsigned card_index, uint32_t mode) {
247 assert(card_index < num_cards);
248 cards[card_index].capture->set_video_mode(mode);
251 void start_mode_scanning(unsigned card_index);
253 std::map<uint32_t, std::string> get_available_video_inputs(unsigned card_index) const {
254 assert(card_index < num_cards);
255 return cards[card_index].capture->get_available_video_inputs();
258 uint32_t get_current_video_input(unsigned card_index) const {
259 assert(card_index < num_cards);
260 return cards[card_index].capture->get_current_video_input();
263 void set_video_input(unsigned card_index, uint32_t input) {
264 assert(card_index < num_cards);
265 cards[card_index].capture->set_video_input(input);
268 std::map<uint32_t, std::string> get_available_audio_inputs(unsigned card_index) const {
269 assert(card_index < num_cards);
270 return cards[card_index].capture->get_available_audio_inputs();
273 uint32_t get_current_audio_input(unsigned card_index) const {
274 assert(card_index < num_cards);
275 return cards[card_index].capture->get_current_audio_input();
278 void set_audio_input(unsigned card_index, uint32_t input) {
279 assert(card_index < num_cards);
280 cards[card_index].capture->set_audio_input(input);
283 void change_x264_bitrate(unsigned rate_kbit) {
284 video_encoder->change_x264_bitrate(rate_kbit);
288 void configure_card(unsigned card_index, bmusb::CaptureInterface *capture, bool is_fake_capture);
289 void bm_frame(unsigned card_index, uint16_t timecode,
290 bmusb::FrameAllocator::Frame video_frame, size_t video_offset, bmusb::VideoFormat video_format,
291 bmusb::FrameAllocator::Frame audio_frame, size_t audio_offset, bmusb::AudioFormat audio_format);
292 void bm_hotplug_add(libusb_device *dev);
293 void bm_hotplug_remove(unsigned card_index);
294 void place_rectangle(movit::Effect *resample_effect, movit::Effect *padding_effect, float x0, float y0, float x1, float y1);
296 void handle_hotplugged_cards();
297 void schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame);
298 void render_one_frame(int64_t duration);
299 void audio_thread_func();
300 void release_display_frame(DisplayFrame *frame);
301 double pts() { return double(pts_int) / TIMEBASE; }
306 QSurface *mixer_surface, *h264_encoder_surface;
307 std::unique_ptr<movit::ResourcePool> resource_pool;
308 std::unique_ptr<Theme> theme;
309 std::atomic<unsigned> audio_source_channel{0};
310 std::atomic<unsigned> master_clock_channel{0};
311 std::unique_ptr<movit::EffectChain> display_chain;
312 std::unique_ptr<ChromaSubsampler> chroma_subsampler;
313 std::unique_ptr<VideoEncoder> video_encoder;
315 // Effects part of <display_chain>. Owned by <display_chain>.
316 movit::FlatInput *display_input;
318 int64_t pts_int = 0; // In TIMEBASE units.
320 // Accumulated errors in number of 1/TIMEBASE audio samples. If OUTPUT_FREQUENCY divided by
321 // frame rate is integer, will always stay zero.
322 unsigned fractional_samples = 0;
324 std::mutex card_mutex;
325 bool has_bmusb_thread = false;
327 bmusb::CaptureInterface *capture = nullptr;
328 bool is_fake_capture;
329 std::unique_ptr<PBOFrameAllocator> frame_allocator;
331 // Stuff for the OpenGL context (for texture uploading).
332 QSurface *surface = nullptr;
335 RefCountedFrame frame;
336 int64_t length; // In TIMEBASE units.
338 unsigned field; // Which field (0 or 1) of the frame to use. Always 0 for progressive.
339 std::function<void()> upload_func; // Needs to be called to actually upload the texture to OpenGL.
340 unsigned dropped_frames = 0; // Number of dropped frames before this one.
341 std::chrono::steady_clock::time_point received_timestamp = std::chrono::steady_clock::time_point::min();
343 std::queue<NewFrame> new_frames;
344 bool should_quit = false;
345 std::condition_variable new_frames_changed; // Set whenever new_frames (or should_quit) is changed.
347 QueueLengthPolicy queue_length_policy; // Refers to the "new_frames" queue.
349 int last_timecode = -1; // Unwrapped.
351 CaptureCard cards[MAX_VIDEO_CARDS]; // Protected by <card_mutex>.
352 AudioMixer audio_mixer; // Same as global_audio_mixer (see audio_mixer.h).
353 struct OutputFrameInfo {
354 int dropped_frames; // Since last frame.
355 int num_samples; // Audio samples needed for this output frame.
356 int64_t frame_duration; // In TIMEBASE units.
358 OutputFrameInfo get_one_frame_from_each_card(unsigned master_card_index, CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS], bool has_new_frame[MAX_VIDEO_CARDS]);
360 InputState input_state;
362 // Cards we have been noticed about being hotplugged, but haven't tried adding yet.
363 // Protected by its own mutex.
364 std::mutex hotplug_mutex;
365 std::vector<libusb_device *> hotplugged_cards;
367 class OutputChannel {
370 void output_frame(DisplayFrame frame);
371 bool get_display_frame(DisplayFrame *frame);
372 void set_frame_ready_callback(new_frame_ready_callback_t callback);
373 void set_transition_names_updated_callback(transition_names_updated_callback_t callback);
374 void set_name_updated_callback(name_updated_callback_t callback);
375 void set_color_updated_callback(color_updated_callback_t callback);
381 Mixer *parent = nullptr; // Not owned.
382 std::mutex frame_mutex;
383 DisplayFrame current_frame, ready_frame; // protected by <frame_mutex>
384 bool has_current_frame = false, has_ready_frame = false; // protected by <frame_mutex>
385 new_frame_ready_callback_t new_frame_ready_callback;
386 transition_names_updated_callback_t transition_names_updated_callback;
387 name_updated_callback_t name_updated_callback;
388 color_updated_callback_t color_updated_callback;
390 std::vector<std::string> last_transition_names;
391 std::string last_name, last_color;
393 OutputChannel output_channel[NUM_OUTPUTS];
395 std::thread mixer_thread;
396 std::thread audio_thread;
397 std::atomic<bool> should_quit{false};
398 std::atomic<bool> should_cut{false};
400 std::unique_ptr<ALSAOutput> alsa;
407 std::mutex audio_mutex;
408 std::condition_variable audio_task_queue_changed;
409 std::queue<AudioTask> audio_task_queue; // Under audio_mutex.
411 // For mode scanning.
412 bool is_mode_scanning[MAX_VIDEO_CARDS]{ false };
413 std::vector<uint32_t> mode_scanlist[MAX_VIDEO_CARDS];
414 unsigned mode_scanlist_index[MAX_VIDEO_CARDS]{ 0 };
415 std::chrono::steady_clock::time_point last_mode_scan_change[MAX_VIDEO_CARDS];
418 extern Mixer *global_mixer;
419 extern bool uses_mlock;
421 #endif // !defined(_MIXER_H)