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"
50 // For any card that's not the master (where we pick out the frames as they
51 // come, as fast as we can process), there's going to be a queue. The question
52 // is when we should drop frames from that queue (apart from the obvious
53 // dropping if the 16-frame queue should become full), especially given that
54 // the frame rate could be lower or higher than the master (either subtly or
55 // dramatically). We have two (conflicting) demands:
57 // 1. We want to avoid starving the queue.
58 // 2. We don't want to add more delay than is needed.
60 // Our general strategy is to drop as many frames as we can (helping for #2)
61 // that we think is safe for #1 given jitter. To this end, we set a lower floor N,
62 // where we assume that if we have N frames in the queue, we're always safe from
63 // starvation. (Typically, N will be 0 or 1. It starts off at 0.) If we have
64 // more than N frames in the queue after reading out the one we need, we head-drop
65 // them to reduce the queue.
67 // N is reduced as follows: If the queue has had at least one spare frame for
68 // at least 50 (master) frames (ie., it's been too conservative for a second),
69 // we reduce N by 1 and reset the timers. TODO: Only do this if N ever actually
72 // Whenever the queue is starved (we needed a frame but there was none),
73 // and we've been at N since the last starvation, N was obviously too low,
74 // so we increment it. We will never set N above 5, though.
75 class QueueLengthPolicy {
77 QueueLengthPolicy() {}
78 void reset(unsigned card_index) {
79 this->card_index = card_index;
80 safe_queue_length = 0;
81 frames_with_at_least_one = 0;
82 been_at_safe_point_since_last_starvation = false;
85 void update_policy(int queue_length); // Give in -1 for starvation.
86 unsigned get_safe_queue_length() const { return safe_queue_length; }
89 unsigned card_index; // For debugging only.
90 unsigned safe_queue_length = 0; // Called N in the comments.
91 unsigned frames_with_at_least_one = 0;
92 bool been_at_safe_point_since_last_starvation = false;
97 // The surface format is used for offscreen destinations for OpenGL contexts we need.
98 Mixer(const QSurfaceFormat &format, unsigned num_cards);
103 void transition_clicked(int transition_num);
104 void channel_clicked(int preview_num);
109 OUTPUT_INPUT0, // 1, 2, 3, up to 15 follow numerically.
113 struct DisplayFrame {
114 // The chain for rendering this frame. To render a display frame,
115 // first wait for <ready_fence>, then call <setup_chain>
116 // to wire up all the inputs, and then finally call
117 // chain->render_to_screen() or similar.
118 movit::EffectChain *chain;
119 std::function<void()> setup_chain;
121 // Asserted when all the inputs are ready; you cannot render the chain
123 RefCountedGLsync ready_fence;
125 // Holds on to all the input frames needed for this display frame,
126 // so they are not released while still rendering.
127 std::vector<RefCountedFrame> input_frames;
129 // Textures that should be released back to the resource pool
130 // when this frame disappears, if any.
131 // TODO: Refcount these as well?
132 std::vector<GLuint> temp_textures;
134 // Implicitly frees the previous one if there's a new frame available.
135 bool get_display_frame(Output output, DisplayFrame *frame) {
136 return output_channel[output].get_display_frame(frame);
139 typedef std::function<void()> new_frame_ready_callback_t;
140 void set_frame_ready_callback(Output output, new_frame_ready_callback_t callback)
142 output_channel[output].set_frame_ready_callback(callback);
145 // TODO: Should this really be per-channel? Shouldn't it just be called for e.g. the live output?
146 typedef std::function<void(const std::vector<std::string> &)> transition_names_updated_callback_t;
147 void set_transition_names_updated_callback(Output output, transition_names_updated_callback_t callback)
149 output_channel[output].set_transition_names_updated_callback(callback);
152 typedef std::function<void(const std::string &)> name_updated_callback_t;
153 void set_name_updated_callback(Output output, name_updated_callback_t callback)
155 output_channel[output].set_name_updated_callback(callback);
158 typedef std::function<void(const std::string &)> color_updated_callback_t;
159 void set_color_updated_callback(Output output, color_updated_callback_t callback)
161 output_channel[output].set_color_updated_callback(callback);
164 std::vector<std::string> get_transition_names()
166 return theme->get_transition_names(pts());
169 unsigned get_num_channels() const
171 return theme->get_num_channels();
174 std::string get_channel_name(unsigned channel) const
176 return theme->get_channel_name(channel);
179 std::string get_channel_color(unsigned channel) const
181 return theme->get_channel_color(channel);
184 int get_channel_signal(unsigned channel) const
186 return theme->get_channel_signal(channel);
189 int map_signal(unsigned channel)
191 return theme->map_signal(channel);
194 unsigned get_master_clock() const
196 return master_clock_channel;
199 void set_master_clock(unsigned channel)
201 master_clock_channel = channel;
204 void set_signal_mapping(int signal, int card)
206 return theme->set_signal_mapping(signal, card);
209 bool get_supports_set_wb(unsigned channel) const
211 return theme->get_supports_set_wb(channel);
214 void set_wb(unsigned channel, double r, double g, double b) const
216 theme->set_wb(channel, r, g, b);
219 // Note: You can also get this through the global variable global_audio_mixer.
220 AudioMixer *get_audio_mixer() { return &audio_mixer; }
221 const AudioMixer *get_audio_mixer() const { return &audio_mixer; }
228 unsigned get_num_cards() const { return num_cards; }
230 std::string get_card_description(unsigned card_index) const {
231 assert(card_index < num_cards);
232 return cards[card_index].capture->get_description();
235 std::map<uint32_t, bmusb::VideoMode> get_available_video_modes(unsigned card_index) const {
236 assert(card_index < num_cards);
237 return cards[card_index].capture->get_available_video_modes();
240 uint32_t get_current_video_mode(unsigned card_index) const {
241 assert(card_index < num_cards);
242 return cards[card_index].capture->get_current_video_mode();
245 void set_video_mode(unsigned card_index, uint32_t mode) {
246 assert(card_index < num_cards);
247 cards[card_index].capture->set_video_mode(mode);
250 void start_mode_scanning(unsigned card_index);
252 std::map<uint32_t, std::string> get_available_video_inputs(unsigned card_index) const {
253 assert(card_index < num_cards);
254 return cards[card_index].capture->get_available_video_inputs();
257 uint32_t get_current_video_input(unsigned card_index) const {
258 assert(card_index < num_cards);
259 return cards[card_index].capture->get_current_video_input();
262 void set_video_input(unsigned card_index, uint32_t input) {
263 assert(card_index < num_cards);
264 cards[card_index].capture->set_video_input(input);
267 std::map<uint32_t, std::string> get_available_audio_inputs(unsigned card_index) const {
268 assert(card_index < num_cards);
269 return cards[card_index].capture->get_available_audio_inputs();
272 uint32_t get_current_audio_input(unsigned card_index) const {
273 assert(card_index < num_cards);
274 return cards[card_index].capture->get_current_audio_input();
277 void set_audio_input(unsigned card_index, uint32_t input) {
278 assert(card_index < num_cards);
279 cards[card_index].capture->set_audio_input(input);
282 void change_x264_bitrate(unsigned rate_kbit) {
283 video_encoder->change_x264_bitrate(rate_kbit);
287 void configure_card(unsigned card_index, bmusb::CaptureInterface *capture, bool is_fake_capture);
288 void bm_frame(unsigned card_index, uint16_t timecode,
289 bmusb::FrameAllocator::Frame video_frame, size_t video_offset, bmusb::VideoFormat video_format,
290 bmusb::FrameAllocator::Frame audio_frame, size_t audio_offset, bmusb::AudioFormat audio_format);
291 void bm_hotplug_add(libusb_device *dev);
292 void bm_hotplug_remove(unsigned card_index);
293 void place_rectangle(movit::Effect *resample_effect, movit::Effect *padding_effect, float x0, float y0, float x1, float y1);
295 void handle_hotplugged_cards();
296 void schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame);
297 void render_one_frame(int64_t duration);
298 void audio_thread_func();
299 void subsample_chroma(GLuint src_tex, GLuint dst_dst);
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 GLuint cbcr_program_num; // Owned by <resource_pool>.
313 GLuint cbcr_vbo; // Holds position and texcoord data.
314 GLuint cbcr_position_attribute_index, cbcr_texcoord_attribute_index;
315 std::unique_ptr<VideoEncoder> video_encoder;
317 // Effects part of <display_chain>. Owned by <display_chain>.
318 movit::FlatInput *display_input;
320 int64_t pts_int = 0; // In TIMEBASE units.
322 std::mutex bmusb_mutex;
323 bool has_bmusb_thread = false;
325 bmusb::CaptureInterface *capture = nullptr;
326 bool is_fake_capture;
327 std::unique_ptr<PBOFrameAllocator> frame_allocator;
329 // Stuff for the OpenGL context (for texture uploading).
330 QSurface *surface = nullptr;
333 RefCountedFrame frame;
334 int64_t length; // In TIMEBASE units.
336 unsigned field; // Which field (0 or 1) of the frame to use. Always 0 for progressive.
337 std::function<void()> upload_func; // Needs to be called to actually upload the texture to OpenGL.
338 unsigned dropped_frames = 0; // Number of dropped frames before this one.
340 std::queue<NewFrame> new_frames;
341 bool should_quit = false;
342 std::condition_variable new_frames_changed; // Set whenever new_frames (or should_quit) is changed.
344 QueueLengthPolicy queue_length_policy; // Refers to the "new_frames" queue.
346 // Accumulated errors in number of 1/TIMEBASE samples. If OUTPUT_FREQUENCY divided by
347 // frame rate is integer, will always stay zero.
348 unsigned fractional_samples = 0;
350 int last_timecode = -1; // Unwrapped.
352 CaptureCard cards[MAX_VIDEO_CARDS]; // protected by <bmusb_mutex>
353 AudioMixer audio_mixer; // Same as global_audio_mixer (see audio_mixer.h).
354 void get_one_frame_from_each_card(unsigned master_card_index, CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS], bool has_new_frame[MAX_VIDEO_CARDS], int num_samples[MAX_VIDEO_CARDS]);
356 InputState input_state;
358 // Cards we have been noticed about being hotplugged, but haven't tried adding yet.
359 // Protected by its own mutex.
360 std::mutex hotplug_mutex;
361 std::vector<libusb_device *> hotplugged_cards;
363 class OutputChannel {
366 void output_frame(DisplayFrame frame);
367 bool get_display_frame(DisplayFrame *frame);
368 void set_frame_ready_callback(new_frame_ready_callback_t callback);
369 void set_transition_names_updated_callback(transition_names_updated_callback_t callback);
370 void set_name_updated_callback(name_updated_callback_t callback);
371 void set_color_updated_callback(color_updated_callback_t callback);
377 Mixer *parent = nullptr; // Not owned.
378 std::mutex frame_mutex;
379 DisplayFrame current_frame, ready_frame; // protected by <frame_mutex>
380 bool has_current_frame = false, has_ready_frame = false; // protected by <frame_mutex>
381 new_frame_ready_callback_t new_frame_ready_callback;
382 transition_names_updated_callback_t transition_names_updated_callback;
383 name_updated_callback_t name_updated_callback;
384 color_updated_callback_t color_updated_callback;
386 std::vector<std::string> last_transition_names;
387 std::string last_name, last_color;
389 OutputChannel output_channel[NUM_OUTPUTS];
391 std::thread mixer_thread;
392 std::thread audio_thread;
393 std::atomic<bool> should_quit{false};
394 std::atomic<bool> should_cut{false};
396 std::unique_ptr<ALSAOutput> alsa;
403 std::mutex audio_mutex;
404 std::condition_variable audio_task_queue_changed;
405 std::queue<AudioTask> audio_task_queue; // Under audio_mutex.
407 // For mode scanning.
408 bool is_mode_scanning[MAX_VIDEO_CARDS]{ false };
409 std::vector<uint32_t> mode_scanlist[MAX_VIDEO_CARDS];
410 unsigned mode_scanlist_index[MAX_VIDEO_CARDS]{ 0 };
411 std::chrono::steady_clock::time_point last_mode_scan_change[MAX_VIDEO_CARDS];
414 extern Mixer *global_mixer;
415 extern bool uses_mlock;
417 #endif // !defined(_MIXER_H)