8 #include <condition_variable>
23 // An interface for frame allocators; if you do not specify one
24 // (using set_video_frame_allocator), a default one that pre-allocates
25 // a freelist of eight frames using new[] will be used. Specifying
26 // your own can be useful if you have special demands for where you want the
27 // frame to end up and don't want to spend the extra copy to get it there, for
28 // instance GPU memory.
29 class FrameAllocator {
32 uint8_t *data = nullptr;
33 uint8_t *data2 = nullptr; // Only if interleaved == true.
34 size_t len = 0; // Number of bytes we actually have.
35 size_t size = 0; // Number of bytes we have room for.
37 void *userdata = nullptr;
38 FrameAllocator *owner = nullptr;
40 // If set to true, every other byte will go to data and to data2.
41 // If so, <len> and <size> are still about the number of total bytes
42 // so if size == 1024, there's 512 bytes in data and 512 in data2.
44 // This doesn't really make any sense if you asked for the
45 // 10BitYCbCr pixel format.
46 bool interleaved = false;
48 // At what point this frame was received. Note that this marks the
49 // _end_ of the frame being received, not the beginning.
50 // Thus, if you want to measure latency, you'll also need to include
51 // the time the frame actually took to transfer (usually 1/fps,
52 // ie., the frames are typically transferred in real time).
53 std::chrono::steady_clock::time_point received_timestamp =
54 std::chrono::steady_clock::time_point::min();
57 virtual ~FrameAllocator();
59 // Request a video frame. Note that this is called from the
60 // USB thread, which runs with realtime priority and is
61 // very sensitive to delays. Thus, you should not do anything
62 // here that might sleep, including calling malloc().
63 // (Taking a mutex is borderline.)
65 // The Frame object will be given to the frame callback,
66 // which is responsible for releasing the video frame back
67 // once it is usable for new frames (ie., it will no longer
68 // be read from). You can use the "userdata" pointer for
69 // whatever you want to identify this frame if you need to.
71 // Returning a Frame with data==nullptr is allowed;
72 // if so, the frame in progress will be dropped.
73 virtual Frame alloc_frame() = 0;
75 virtual void release_frame(Frame frame) = 0;
78 // Audio is more important than video, and also much cheaper.
79 // By having many more audio frames available, hopefully if something
80 // starts to drop, we'll have CPU load go down (from not having to
81 // process as much video) before we have to drop audio.
82 #define NUM_QUEUED_VIDEO_FRAMES 16
83 #define NUM_QUEUED_AUDIO_FRAMES 64
85 class MallocFrameAllocator : public FrameAllocator {
87 MallocFrameAllocator(size_t frame_size, size_t num_queued_frames);
88 Frame alloc_frame() override;
89 void release_frame(Frame frame) override;
94 std::mutex freelist_mutex;
95 std::stack<std::unique_ptr<uint8_t[]>> freelist; // All of size <frame_size>.
98 // Represents an input mode you can tune a card to.
101 bool autodetect = false; // If true, all the remaining fields are irrelevant.
102 unsigned width = 0, height = 0;
103 unsigned frame_rate_num = 0, frame_rate_den = 0;
104 bool interlaced = false;
107 // Represents the format of an actual frame coming in.
108 // Note: Frame rate is _frame_ rate, not field rate. So 1080i60 gets 30/1, _not_ 60/1.
109 // "second_field_start" is only valid for interlaced modes. If it is 1,
110 // the two fields are actually stored interlaced (ie., every other line).
111 // If not, each field is stored consecutively, and it signifies how many lines
112 // from the very top of the frame there are before the second field
113 // starts (so it will always be >= height/2 + extra_lines_top).
115 uint16_t id = 0; // For debugging/logging only.
116 unsigned width = 0, height = 0, second_field_start = 0;
117 unsigned extra_lines_top = 0, extra_lines_bottom = 0;
118 unsigned frame_rate_nom = 0, frame_rate_den = 0;
119 unsigned stride = 0; // In bytes, assuming no interleaving.
120 bool interlaced = false;
121 bool has_signal = false;
122 bool is_connected = true; // If false, then has_signal makes no sense.
126 uint16_t id = 0; // For debugging/logging only.
127 unsigned bits_per_sample = 0;
128 unsigned num_channels = 0;
132 // 8-bit 4:2:2 in the standard Cb Y Cr Y order (UYVY).
133 // This is the default.
134 PixelFormat_8BitYCbCr,
136 // 10-bit 4:2:2 in v210 order. Six pixels (six Y', three Cb,
137 // three Cr) are packed into four 32-bit little-endian ints
138 // in the following pattern (see e.g. the DeckLink documentation
148 // If you read in RGB order and ignore the unused top bits,
149 // this is essentially Cb Y Cr Y order, just like UYVY is.
151 // Note that unlike true v210, there is no guarantee about
152 // 128-byte line alignment (or lack thereof); you should check
153 // the stride member of VideoFormat.
154 PixelFormat_10BitYCbCr
157 typedef std::function<void(uint16_t timecode,
158 FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
159 FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)>
162 typedef std::function<void(libusb_device *dev)> card_connected_callback_t;
163 typedef std::function<void()> card_disconnected_callback_t;
165 class CaptureInterface {
167 virtual ~CaptureInterface() {}
169 virtual std::map<uint32_t, VideoMode> get_available_video_modes() const = 0;
170 virtual uint32_t get_current_video_mode() const = 0;
171 virtual void set_video_mode(uint32_t video_mode_id) = 0;
173 // TODO: Add a way to query this based on mode?
174 virtual std::set<PixelFormat> get_available_pixel_formats() const = 0;
175 virtual void set_pixel_format(PixelFormat pixel_format) = 0;
176 virtual PixelFormat get_current_pixel_format() const = 0;
178 virtual std::map<uint32_t, std::string> get_available_video_inputs() const = 0;
179 virtual void set_video_input(uint32_t video_input_id) = 0;
180 virtual uint32_t get_current_video_input() const = 0;
182 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const = 0;
183 virtual void set_audio_input(uint32_t audio_input_id) = 0;
184 virtual uint32_t get_current_audio_input() const = 0;
186 // Does not take ownership.
187 virtual void set_video_frame_allocator(FrameAllocator *allocator) = 0;
189 virtual FrameAllocator *get_video_frame_allocator() = 0;
191 // Does not take ownership.
192 virtual void set_audio_frame_allocator(FrameAllocator *allocator) = 0;
194 virtual FrameAllocator *get_audio_frame_allocator() = 0;
196 virtual void set_frame_callback(frame_callback_t callback) = 0;
198 // Needs to be run before configure_card().
199 virtual void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) = 0;
201 // Only valid after configure_card().
202 virtual std::string get_description() const = 0;
204 virtual void configure_card() = 0;
206 virtual void start_bm_capture() = 0;
208 virtual void stop_dequeue_thread() = 0;
210 // If a card is disconnected, it cannot come back; you should call stop_dequeue_thread()
212 virtual bool get_disconnected() const = 0;
215 // The actual capturing class, representing capture from a single card.
216 class BMUSBCapture : public CaptureInterface {
218 BMUSBCapture(int card_index, libusb_device *dev = nullptr)
219 : card_index(card_index), dev(dev)
225 // Note: Cards could be unplugged and replugged between this call and
226 // actually opening the card (in configure_card()).
227 static unsigned num_cards();
229 std::set<PixelFormat> get_available_pixel_formats() const override
231 return std::set<PixelFormat>{ PixelFormat_8BitYCbCr, PixelFormat_10BitYCbCr };
234 void set_pixel_format(PixelFormat pixel_format) override;
236 PixelFormat get_current_pixel_format() const
238 return current_pixel_format;
241 std::map<uint32_t, VideoMode> get_available_video_modes() const override;
242 uint32_t get_current_video_mode() const override;
243 void set_video_mode(uint32_t video_mode_id) override;
245 virtual std::map<uint32_t, std::string> get_available_video_inputs() const override;
246 virtual void set_video_input(uint32_t video_input_id) override;
247 virtual uint32_t get_current_video_input() const override { return current_video_input; }
249 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const override;
250 virtual void set_audio_input(uint32_t audio_input_id) override;
251 virtual uint32_t get_current_audio_input() const override { return current_audio_input; }
253 // Does not take ownership.
254 void set_video_frame_allocator(FrameAllocator *allocator) override
256 video_frame_allocator = allocator;
257 if (owned_video_frame_allocator.get() != allocator) {
258 owned_video_frame_allocator.reset();
262 FrameAllocator *get_video_frame_allocator() override
264 return video_frame_allocator;
267 // Does not take ownership.
268 void set_audio_frame_allocator(FrameAllocator *allocator) override
270 audio_frame_allocator = allocator;
271 if (owned_audio_frame_allocator.get() != allocator) {
272 owned_audio_frame_allocator.reset();
276 FrameAllocator *get_audio_frame_allocator() override
278 return audio_frame_allocator;
281 void set_frame_callback(frame_callback_t callback) override
283 frame_callback = callback;
286 // Needs to be run before configure_card().
287 void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) override
289 dequeue_init_callback = init;
290 dequeue_cleanup_callback = cleanup;
291 has_dequeue_callbacks = true;
294 // Only valid after configure_card().
295 std::string get_description() const override {
299 void configure_card() override;
300 void start_bm_capture() override;
301 void stop_dequeue_thread() override;
302 bool get_disconnected() const override { return disconnected; }
304 // TODO: It's rather messy to have these outside the interface.
305 static void start_bm_thread();
306 static void stop_bm_thread();
308 // Hotplug event (for devices being inserted between start_bm_thread()
309 // and stop_bm_thread()); entirely optional, but must be set before
310 // start_bm_capture(). Note that your callback should do as little work
311 // as possible, since the callback comes from the main USB handling
312 // thread, which is very time-sensitive.
314 // The callback function transfers ownership. If you don't want to hold
315 // on to the device given to you in the callback, you need to call
316 // libusb_unref_device().
317 static void set_card_connected_callback(card_connected_callback_t callback,
318 bool hotplug_existing_devices_arg = false)
320 card_connected_callback = callback;
321 hotplug_existing_devices = hotplug_existing_devices_arg;
324 // Similar to set_card_connected_callback(), with the same caveats.
325 // (Note that this is set per-card and not global, as it is logically
326 // connected to an existing BMUSBCapture object.)
327 void set_card_disconnected_callback(card_disconnected_callback_t callback)
329 card_disconnected_callback = callback;
336 FrameAllocator::Frame frame;
339 void start_new_audio_block(const uint8_t *start);
340 void start_new_frame(const uint8_t *start);
342 void queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame, std::deque<QueuedFrame> *q);
343 void dequeue_thread_func();
345 static void usb_thread_func();
346 static void cb_xfr(struct libusb_transfer *xfr);
347 static int cb_hotplug(libusb_context *ctx, libusb_device *dev, libusb_hotplug_event event, void *user_data);
349 void update_capture_mode();
351 std::string description;
353 FrameAllocator::Frame current_video_frame;
354 FrameAllocator::Frame current_audio_frame;
356 std::mutex queue_lock;
357 std::condition_variable queues_not_empty;
358 std::deque<QueuedFrame> pending_video_frames;
359 std::deque<QueuedFrame> pending_audio_frames;
361 FrameAllocator *video_frame_allocator = nullptr;
362 FrameAllocator *audio_frame_allocator = nullptr;
363 std::unique_ptr<FrameAllocator> owned_video_frame_allocator;
364 std::unique_ptr<FrameAllocator> owned_audio_frame_allocator;
365 frame_callback_t frame_callback = nullptr;
366 static card_connected_callback_t card_connected_callback;
367 static bool hotplug_existing_devices;
368 card_disconnected_callback_t card_disconnected_callback = nullptr;
370 std::thread dequeue_thread;
371 std::atomic<bool> dequeue_thread_should_quit;
372 bool has_dequeue_callbacks = false;
373 std::function<void()> dequeue_init_callback = nullptr;
374 std::function<void()> dequeue_cleanup_callback = nullptr;
376 int current_register = 0;
378 static constexpr int NUM_BMUSB_REGISTERS = 60;
379 uint8_t register_file[NUM_BMUSB_REGISTERS];
381 // If <dev> is nullptr, will choose device number <card_index> from the list
382 // of available devices on the system. <dev> is not used after configure_card()
383 // (it will be unref-ed).
385 libusb_device *dev = nullptr;
387 std::vector<libusb_transfer *> iso_xfrs;
388 int assumed_frame_width = 1280;
390 libusb_device_handle *devh = nullptr;
391 uint32_t current_video_input = 0x00000000; // HDMI/SDI.
392 uint32_t current_audio_input = 0x00000000; // Embedded.
393 PixelFormat current_pixel_format = PixelFormat_8BitYCbCr;
395 bool disconnected = false;