4 // The actual video mixer, running in its own separate background thread.
10 #include <movit/effect_chain.h>
11 #include <movit/flat_input.h>
17 #include <condition_variable>
28 #include "alsa_output.h"
29 #include "audio_mixer.h"
30 #include "bmusb/bmusb.h"
33 #include "input_state.h"
34 #include "pbo_frame_allocator.h"
35 #include "ref_counted_frame.h"
36 #include "ref_counted_gl_sync.h"
37 #include "resampling_queue.h"
40 #include "stereocompressor.h"
41 #include "video_encoder.h"
45 class QuickSyncEncoder;
58 // For any card that's not the master (where we pick out the frames as they
59 // come, as fast as we can process), there's going to be a queue. The question
60 // is when we should drop frames from that queue (apart from the obvious
61 // dropping if the 16-frame queue should become full), especially given that
62 // the frame rate could be lower or higher than the master (either subtly or
63 // dramatically). We have two (conflicting) demands:
65 // 1. We want to avoid starving the queue.
66 // 2. We don't want to add more delay than is needed.
68 // Our general strategy is to drop as many frames as we can (helping for #2)
69 // that we think is safe for #1 given jitter. To this end, we set a lower floor N,
70 // where we assume that if we have N frames in the queue, we're always safe from
71 // starvation. (Typically, N will be 0 or 1. It starts off at 0.) If we have
72 // more than N frames in the queue after reading out the one we need, we head-drop
73 // them to reduce the queue.
75 // N is reduced as follows: If the queue has had at least one spare frame for
76 // at least 50 (master) frames (ie., it's been too conservative for a second),
77 // we reduce N by 1 and reset the timers. TODO: Only do this if N ever actually
80 // Whenever the queue is starved (we needed a frame but there was none),
81 // and we've been at N since the last starvation, N was obviously too low,
82 // so we increment it. We will never set N above 5, though.
83 class QueueLengthPolicy {
85 QueueLengthPolicy() {}
86 void reset(unsigned card_index) {
87 this->card_index = card_index;
88 safe_queue_length = 0;
89 frames_with_at_least_one = 0;
90 been_at_safe_point_since_last_starvation = false;
93 void update_policy(int queue_length); // Give in -1 for starvation.
94 unsigned get_safe_queue_length() const { return safe_queue_length; }
97 unsigned card_index; // For debugging only.
98 unsigned safe_queue_length = 0; // Called N in the comments.
99 unsigned frames_with_at_least_one = 0;
100 bool been_at_safe_point_since_last_starvation = false;
105 // The surface format is used for offscreen destinations for OpenGL contexts we need.
106 Mixer(const QSurfaceFormat &format, unsigned num_cards);
111 void transition_clicked(int transition_num);
112 void channel_clicked(int preview_num);
117 OUTPUT_INPUT0, // 1, 2, 3, up to 15 follow numerically.
121 struct DisplayFrame {
122 // The chain for rendering this frame. To render a display frame,
123 // first wait for <ready_fence>, then call <setup_chain>
124 // to wire up all the inputs, and then finally call
125 // chain->render_to_screen() or similar.
126 movit::EffectChain *chain;
127 std::function<void()> setup_chain;
129 // Asserted when all the inputs are ready; you cannot render the chain
131 RefCountedGLsync ready_fence;
133 // Holds on to all the input frames needed for this display frame,
134 // so they are not released while still rendering.
135 std::vector<RefCountedFrame> input_frames;
137 // Textures that should be released back to the resource pool
138 // when this frame disappears, if any.
139 // TODO: Refcount these as well?
140 std::vector<GLuint> temp_textures;
142 // Implicitly frees the previous one if there's a new frame available.
143 bool get_display_frame(Output output, DisplayFrame *frame) {
144 return output_channel[output].get_display_frame(frame);
147 typedef std::function<void()> new_frame_ready_callback_t;
148 void set_frame_ready_callback(Output output, new_frame_ready_callback_t callback)
150 output_channel[output].set_frame_ready_callback(callback);
153 // TODO: Should this really be per-channel? Shouldn't it just be called for e.g. the live output?
154 typedef std::function<void(const std::vector<std::string> &)> transition_names_updated_callback_t;
155 void set_transition_names_updated_callback(Output output, transition_names_updated_callback_t callback)
157 output_channel[output].set_transition_names_updated_callback(callback);
160 typedef std::function<void(const std::string &)> name_updated_callback_t;
161 void set_name_updated_callback(Output output, name_updated_callback_t callback)
163 output_channel[output].set_name_updated_callback(callback);
166 typedef std::function<void(const std::string &)> color_updated_callback_t;
167 void set_color_updated_callback(Output output, color_updated_callback_t callback)
169 output_channel[output].set_color_updated_callback(callback);
172 std::vector<std::string> get_transition_names()
174 return theme->get_transition_names(pts());
177 unsigned get_num_channels() const
179 return theme->get_num_channels();
182 std::string get_channel_name(unsigned channel) const
184 return theme->get_channel_name(channel);
187 std::string get_channel_color(unsigned channel) const
189 return theme->get_channel_color(channel);
192 int get_channel_signal(unsigned channel) const
194 return theme->get_channel_signal(channel);
197 int map_signal(unsigned channel)
199 return theme->map_signal(channel);
202 unsigned get_master_clock() const
204 return master_clock_channel;
207 void set_master_clock(unsigned channel)
209 master_clock_channel = channel;
212 void set_signal_mapping(int signal, int card)
214 return theme->set_signal_mapping(signal, card);
217 bool get_supports_set_wb(unsigned channel) const
219 return theme->get_supports_set_wb(channel);
222 void set_wb(unsigned channel, double r, double g, double b) const
224 theme->set_wb(channel, r, g, b);
227 // Note: You can also get this through the global variable global_audio_mixer.
228 AudioMixer *get_audio_mixer() { return &audio_mixer; }
229 const AudioMixer *get_audio_mixer() const { return &audio_mixer; }
236 unsigned get_num_cards() const { return num_cards; }
238 std::string get_card_description(unsigned card_index) const {
239 assert(card_index < num_cards);
240 return cards[card_index].capture->get_description();
243 std::map<uint32_t, bmusb::VideoMode> get_available_video_modes(unsigned card_index) const {
244 assert(card_index < num_cards);
245 return cards[card_index].capture->get_available_video_modes();
248 uint32_t get_current_video_mode(unsigned card_index) const {
249 assert(card_index < num_cards);
250 return cards[card_index].capture->get_current_video_mode();
253 void set_video_mode(unsigned card_index, uint32_t mode) {
254 assert(card_index < num_cards);
255 cards[card_index].capture->set_video_mode(mode);
258 void start_mode_scanning(unsigned card_index);
260 std::map<uint32_t, std::string> get_available_video_inputs(unsigned card_index) const {
261 assert(card_index < num_cards);
262 return cards[card_index].capture->get_available_video_inputs();
265 uint32_t get_current_video_input(unsigned card_index) const {
266 assert(card_index < num_cards);
267 return cards[card_index].capture->get_current_video_input();
270 void set_video_input(unsigned card_index, uint32_t input) {
271 assert(card_index < num_cards);
272 cards[card_index].capture->set_video_input(input);
275 std::map<uint32_t, std::string> get_available_audio_inputs(unsigned card_index) const {
276 assert(card_index < num_cards);
277 return cards[card_index].capture->get_available_audio_inputs();
280 uint32_t get_current_audio_input(unsigned card_index) const {
281 assert(card_index < num_cards);
282 return cards[card_index].capture->get_current_audio_input();
285 void set_audio_input(unsigned card_index, uint32_t input) {
286 assert(card_index < num_cards);
287 cards[card_index].capture->set_audio_input(input);
290 void change_x264_bitrate(unsigned rate_kbit) {
291 video_encoder->change_x264_bitrate(rate_kbit);
295 void configure_card(unsigned card_index, bmusb::CaptureInterface *capture, bool is_fake_capture);
296 void bm_frame(unsigned card_index, uint16_t timecode,
297 bmusb::FrameAllocator::Frame video_frame, size_t video_offset, bmusb::VideoFormat video_format,
298 bmusb::FrameAllocator::Frame audio_frame, size_t audio_offset, bmusb::AudioFormat audio_format);
299 void bm_hotplug_add(libusb_device *dev);
300 void bm_hotplug_remove(unsigned card_index);
301 void place_rectangle(movit::Effect *resample_effect, movit::Effect *padding_effect, float x0, float y0, float x1, float y1);
303 void handle_hotplugged_cards();
304 void schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame);
305 void render_one_frame(int64_t duration);
306 void audio_thread_func();
307 void subsample_chroma(GLuint src_tex, GLuint dst_dst);
308 void release_display_frame(DisplayFrame *frame);
309 double pts() { return double(pts_int) / TIMEBASE; }
314 QSurface *mixer_surface, *h264_encoder_surface;
315 std::unique_ptr<movit::ResourcePool> resource_pool;
316 std::unique_ptr<Theme> theme;
317 std::atomic<unsigned> audio_source_channel{0};
318 std::atomic<unsigned> master_clock_channel{0};
319 std::unique_ptr<movit::EffectChain> display_chain;
320 GLuint cbcr_program_num; // Owned by <resource_pool>.
321 GLuint cbcr_vbo; // Holds position and texcoord data.
322 GLuint cbcr_position_attribute_index, cbcr_texcoord_attribute_index;
323 std::unique_ptr<VideoEncoder> video_encoder;
325 // Effects part of <display_chain>. Owned by <display_chain>.
326 movit::FlatInput *display_input;
328 int64_t pts_int = 0; // In TIMEBASE units.
330 std::mutex bmusb_mutex;
331 bool has_bmusb_thread = false;
333 bmusb::CaptureInterface *capture = nullptr;
334 bool is_fake_capture;
335 std::unique_ptr<PBOFrameAllocator> frame_allocator;
337 // Stuff for the OpenGL context (for texture uploading).
338 QSurface *surface = nullptr;
341 RefCountedFrame frame;
342 int64_t length; // In TIMEBASE units.
344 unsigned field; // Which field (0 or 1) of the frame to use. Always 0 for progressive.
345 std::function<void()> upload_func; // Needs to be called to actually upload the texture to OpenGL.
346 unsigned dropped_frames = 0; // Number of dropped frames before this one.
348 std::queue<NewFrame> new_frames;
349 bool should_quit = false;
350 std::condition_variable new_frames_changed; // Set whenever new_frames (or should_quit) is changed.
352 QueueLengthPolicy queue_length_policy; // Refers to the "new_frames" queue.
354 // Accumulated errors in number of 1/TIMEBASE samples. If OUTPUT_FREQUENCY divided by
355 // frame rate is integer, will always stay zero.
356 unsigned fractional_samples = 0;
358 int last_timecode = -1; // Unwrapped.
360 CaptureCard cards[MAX_VIDEO_CARDS]; // protected by <bmusb_mutex>
361 AudioMixer audio_mixer; // Same as global_audio_mixer (see audio_mixer.h).
362 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]);
364 InputState input_state;
366 // Cards we have been noticed about being hotplugged, but haven't tried adding yet.
367 // Protected by its own mutex.
368 std::mutex hotplug_mutex;
369 std::vector<libusb_device *> hotplugged_cards;
371 class OutputChannel {
374 void output_frame(DisplayFrame frame);
375 bool get_display_frame(DisplayFrame *frame);
376 void set_frame_ready_callback(new_frame_ready_callback_t callback);
377 void set_transition_names_updated_callback(transition_names_updated_callback_t callback);
378 void set_name_updated_callback(name_updated_callback_t callback);
379 void set_color_updated_callback(color_updated_callback_t callback);
385 Mixer *parent = nullptr; // Not owned.
386 std::mutex frame_mutex;
387 DisplayFrame current_frame, ready_frame; // protected by <frame_mutex>
388 bool has_current_frame = false, has_ready_frame = false; // protected by <frame_mutex>
389 new_frame_ready_callback_t new_frame_ready_callback;
390 transition_names_updated_callback_t transition_names_updated_callback;
391 name_updated_callback_t name_updated_callback;
392 color_updated_callback_t color_updated_callback;
394 std::vector<std::string> last_transition_names;
395 std::string last_name, last_color;
397 OutputChannel output_channel[NUM_OUTPUTS];
399 std::thread mixer_thread;
400 std::thread audio_thread;
401 std::atomic<bool> should_quit{false};
402 std::atomic<bool> should_cut{false};
404 std::unique_ptr<ALSAOutput> alsa;
411 std::mutex audio_mutex;
412 std::condition_variable audio_task_queue_changed;
413 std::queue<AudioTask> audio_task_queue; // Under audio_mutex.
415 // For mode scanning.
416 bool is_mode_scanning[MAX_VIDEO_CARDS]{ false };
417 std::vector<uint32_t> mode_scanlist[MAX_VIDEO_CARDS];
418 unsigned mode_scanlist_index[MAX_VIDEO_CARDS]{ 0 };
419 std::chrono::steady_clock::time_point last_mode_scan_change[MAX_VIDEO_CARDS];
422 extern Mixer *global_mixer;
423 extern bool uses_mlock;
425 #endif // !defined(_MIXER_H)