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 uint8_t *data_copy = nullptr; // Will get a non-interleaved copy if not nullptr.
35 size_t len = 0; // Number of bytes we actually have.
36 size_t size = 0; // Number of bytes we have room for.
38 void *userdata = nullptr;
39 FrameAllocator *owner = nullptr;
41 // If set to true, every other byte will go to data and to data2.
42 // If so, <len> and <size> are still about the number of total bytes
43 // so if size == 1024, there's 512 bytes in data and 512 in data2.
45 // This doesn't really make any sense if you asked for the
46 // 10BitYCbCr pixel format.
47 bool interleaved = false;
49 // At what point this frame was received. Note that this marks the
50 // _end_ of the frame being received, not the beginning.
51 // Thus, if you want to measure latency, you'll also need to include
52 // the time the frame actually took to transfer (usually 1/fps,
53 // ie., the frames are typically transferred in real time).
54 std::chrono::steady_clock::time_point received_timestamp =
55 std::chrono::steady_clock::time_point::min();
58 virtual ~FrameAllocator();
60 // Request a video frame. Note that this is called from the
61 // USB thread, which runs with realtime priority and is
62 // very sensitive to delays. Thus, you should not do anything
63 // here that might sleep, including calling malloc().
64 // (Taking a mutex is borderline.)
66 // The Frame object will be given to the frame callback,
67 // which is responsible for releasing the video frame back
68 // once it is usable for new frames (ie., it will no longer
69 // be read from). You can use the "userdata" pointer for
70 // whatever you want to identify this frame if you need to.
72 // Returning a Frame with data==nullptr is allowed;
73 // if so, the frame in progress will be dropped.
74 virtual Frame alloc_frame() = 0;
76 virtual void release_frame(Frame frame) = 0;
79 // Audio is more important than video, and also much cheaper.
80 // By having many more audio frames available, hopefully if something
81 // starts to drop, we'll have CPU load go down (from not having to
82 // process as much video) before we have to drop audio.
83 #define NUM_QUEUED_VIDEO_FRAMES 16
84 #define NUM_QUEUED_AUDIO_FRAMES 64
86 class MallocFrameAllocator : public FrameAllocator {
88 MallocFrameAllocator(size_t frame_size, size_t num_queued_frames);
89 Frame alloc_frame() override;
90 void release_frame(Frame frame) override;
95 std::mutex freelist_mutex;
96 std::stack<std::unique_ptr<uint8_t[]>> freelist; // All of size <frame_size>.
99 // Represents an input mode you can tune a card to.
102 bool autodetect = false; // If true, all the remaining fields are irrelevant.
103 unsigned width = 0, height = 0;
104 unsigned frame_rate_num = 0, frame_rate_den = 0;
105 bool interlaced = false;
108 // Represents the format of an actual frame coming in.
109 // Note: Frame rate is _frame_ rate, not field rate. So 1080i60 gets 30/1, _not_ 60/1.
110 // "second_field_start" is only valid for interlaced modes. If it is 1,
111 // the two fields are actually stored interlaced (ie., every other line).
112 // If not, each field is stored consecutively, and it signifies how many lines
113 // from the very top of the frame there are before the second field
114 // starts (so it will always be >= height/2 + extra_lines_top).
116 uint16_t id = 0; // For debugging/logging only.
117 unsigned width = 0, height = 0, second_field_start = 0;
118 unsigned extra_lines_top = 0, extra_lines_bottom = 0;
119 unsigned frame_rate_nom = 0, frame_rate_den = 0;
120 unsigned stride = 0; // In bytes, assuming no interleaving.
121 bool interlaced = false;
122 bool has_signal = false;
123 bool is_connected = true; // If false, then has_signal makes no sense.
127 uint16_t id = 0; // For debugging/logging only.
128 unsigned bits_per_sample = 0;
129 unsigned num_channels = 0;
130 unsigned sample_rate = 48000;
134 // 8-bit 4:2:2 in the standard Cb Y Cr Y order (UYVY).
135 // This is the default.
136 PixelFormat_8BitYCbCr,
138 // 10-bit 4:2:2 in v210 order. Six pixels (six Y', three Cb,
139 // three Cr) are packed into four 32-bit little-endian ints
140 // in the following pattern (see e.g. the DeckLink documentation
150 // If you read in RGB order and ignore the unused top bits,
151 // this is essentially Cb Y Cr Y order, just like UYVY is.
153 // Note that unlike true v210, there is no guarantee about
154 // 128-byte line alignment (or lack thereof); you should check
155 // the stride member of VideoFormat.
156 PixelFormat_10BitYCbCr,
158 // 8-bit 4:4:4:4 BGRA (in that order). bmusb itself doesn't
159 // produce this, but it is useful to represent e.g. synthetic inputs.
160 PixelFormat_8BitBGRA,
162 // 8-bit 4:2:0, 4:2:2, 4:4:4 or really anything else, planar
163 // (ie., first all Y', then all Cb, then all Cr). bmusb doesn't
164 // produce this, nor does it specify a mechanism to describe
165 // the precise details of the format.
166 PixelFormat_8BitYCbCrPlanar,
168 // These exist only so that the type is guaranteed wide enough
169 // to contain values up to 127. CaptureInterface instances
170 // are free to use them as they see fit for private uses.
171 PixelFormat_Unused100 = 100,
172 PixelFormat_Unused127 = 127
175 typedef std::function<void(uint16_t timecode,
176 FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
177 FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)>
180 typedef std::function<void(libusb_device *dev)> card_connected_callback_t;
181 typedef std::function<void()> card_disconnected_callback_t;
183 class CaptureInterface {
185 virtual ~CaptureInterface() {}
187 virtual std::map<uint32_t, VideoMode> get_available_video_modes() const = 0;
188 virtual uint32_t get_current_video_mode() const = 0;
189 virtual void set_video_mode(uint32_t video_mode_id) = 0;
191 // TODO: Add a way to query this based on mode?
192 virtual std::set<PixelFormat> get_available_pixel_formats() const = 0;
193 virtual void set_pixel_format(PixelFormat pixel_format) = 0;
194 virtual PixelFormat get_current_pixel_format() const = 0;
196 virtual std::map<uint32_t, std::string> get_available_video_inputs() const = 0;
197 virtual void set_video_input(uint32_t video_input_id) = 0;
198 virtual uint32_t get_current_video_input() const = 0;
200 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const = 0;
201 virtual void set_audio_input(uint32_t audio_input_id) = 0;
202 virtual uint32_t get_current_audio_input() const = 0;
204 // Does not take ownership.
205 virtual void set_video_frame_allocator(FrameAllocator *allocator) = 0;
207 virtual FrameAllocator *get_video_frame_allocator() = 0;
209 // Does not take ownership.
210 virtual void set_audio_frame_allocator(FrameAllocator *allocator) = 0;
212 virtual FrameAllocator *get_audio_frame_allocator() = 0;
214 virtual void set_frame_callback(frame_callback_t callback) = 0;
216 // Needs to be run before configure_card().
217 virtual void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) = 0;
219 // Only valid after configure_card().
220 virtual std::string get_description() const = 0;
222 virtual void configure_card() = 0;
224 virtual void start_bm_capture() = 0;
226 virtual void stop_dequeue_thread() = 0;
228 // If a card is disconnected, it cannot come back; you should call stop_dequeue_thread()
230 virtual bool get_disconnected() const = 0;
233 // The actual capturing class, representing capture from a single card.
234 class BMUSBCapture : public CaptureInterface {
236 BMUSBCapture(int card_index, libusb_device *dev = nullptr)
237 : card_index(card_index), dev(dev)
243 // Note: Cards could be unplugged and replugged between this call and
244 // actually opening the card (in configure_card()).
245 static unsigned num_cards();
247 std::set<PixelFormat> get_available_pixel_formats() const override
249 return std::set<PixelFormat>{ PixelFormat_8BitYCbCr, PixelFormat_10BitYCbCr };
252 void set_pixel_format(PixelFormat pixel_format) override;
254 PixelFormat get_current_pixel_format() const
256 return current_pixel_format;
259 std::map<uint32_t, VideoMode> get_available_video_modes() const override;
260 uint32_t get_current_video_mode() const override;
261 void set_video_mode(uint32_t video_mode_id) override;
263 virtual std::map<uint32_t, std::string> get_available_video_inputs() const override;
264 virtual void set_video_input(uint32_t video_input_id) override;
265 virtual uint32_t get_current_video_input() const override { return current_video_input; }
267 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const override;
268 virtual void set_audio_input(uint32_t audio_input_id) override;
269 virtual uint32_t get_current_audio_input() const override { return current_audio_input; }
271 // Does not take ownership.
272 void set_video_frame_allocator(FrameAllocator *allocator) override
274 video_frame_allocator = allocator;
275 if (owned_video_frame_allocator.get() != allocator) {
276 owned_video_frame_allocator.reset();
280 FrameAllocator *get_video_frame_allocator() override
282 return video_frame_allocator;
285 // Does not take ownership.
286 void set_audio_frame_allocator(FrameAllocator *allocator) override
288 audio_frame_allocator = allocator;
289 if (owned_audio_frame_allocator.get() != allocator) {
290 owned_audio_frame_allocator.reset();
294 FrameAllocator *get_audio_frame_allocator() override
296 return audio_frame_allocator;
299 void set_frame_callback(frame_callback_t callback) override
301 frame_callback = callback;
304 // Needs to be run before configure_card().
305 void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) override
307 dequeue_init_callback = init;
308 dequeue_cleanup_callback = cleanup;
309 has_dequeue_callbacks = true;
312 // Only valid after configure_card().
313 std::string get_description() const override {
317 void configure_card() override;
318 void start_bm_capture() override;
319 void stop_dequeue_thread() override;
320 bool get_disconnected() const override { return disconnected; }
322 // TODO: It's rather messy to have these outside the interface.
323 static void start_bm_thread();
324 static void stop_bm_thread();
326 // Hotplug event (for devices being inserted between start_bm_thread()
327 // and stop_bm_thread()); entirely optional, but must be set before
328 // start_bm_capture(). Note that your callback should do as little work
329 // as possible, since the callback comes from the main USB handling
330 // thread, which is very time-sensitive.
332 // The callback function transfers ownership. If you don't want to hold
333 // on to the device given to you in the callback, you need to call
334 // libusb_unref_device().
335 static void set_card_connected_callback(card_connected_callback_t callback,
336 bool hotplug_existing_devices_arg = false)
338 card_connected_callback = callback;
339 hotplug_existing_devices = hotplug_existing_devices_arg;
342 // Similar to set_card_connected_callback(), with the same caveats.
343 // (Note that this is set per-card and not global, as it is logically
344 // connected to an existing BMUSBCapture object.)
345 void set_card_disconnected_callback(card_disconnected_callback_t callback)
347 card_disconnected_callback = callback;
354 FrameAllocator::Frame frame;
357 void start_new_audio_block(const uint8_t *start);
358 void start_new_frame(const uint8_t *start);
360 void queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame, std::deque<QueuedFrame> *q);
361 void dequeue_thread_func();
363 static void usb_thread_func();
364 static void cb_xfr(struct libusb_transfer *xfr);
365 static int cb_hotplug(libusb_context *ctx, libusb_device *dev, libusb_hotplug_event event, void *user_data);
367 void update_capture_mode();
369 std::string description;
371 FrameAllocator::Frame current_video_frame;
372 FrameAllocator::Frame current_audio_frame;
374 std::mutex queue_lock;
375 std::condition_variable queues_not_empty;
376 std::deque<QueuedFrame> pending_video_frames;
377 std::deque<QueuedFrame> pending_audio_frames;
379 FrameAllocator *video_frame_allocator = nullptr;
380 FrameAllocator *audio_frame_allocator = nullptr;
381 std::unique_ptr<FrameAllocator> owned_video_frame_allocator;
382 std::unique_ptr<FrameAllocator> owned_audio_frame_allocator;
383 frame_callback_t frame_callback = nullptr;
384 static card_connected_callback_t card_connected_callback;
385 static bool hotplug_existing_devices;
386 card_disconnected_callback_t card_disconnected_callback = nullptr;
388 std::thread dequeue_thread;
389 std::atomic<bool> dequeue_thread_should_quit;
390 bool has_dequeue_callbacks = false;
391 std::function<void()> dequeue_init_callback = nullptr;
392 std::function<void()> dequeue_cleanup_callback = nullptr;
394 int current_register = 0;
396 static constexpr int NUM_BMUSB_REGISTERS = 60;
397 uint8_t register_file[NUM_BMUSB_REGISTERS];
399 // If <dev> is nullptr, will choose device number <card_index> from the list
400 // of available devices on the system. <dev> is not used after configure_card()
401 // (it will be unref-ed).
403 libusb_device *dev = nullptr;
405 std::vector<libusb_transfer *> iso_xfrs;
406 int assumed_frame_width = 1280;
408 libusb_device_handle *devh = nullptr;
409 uint32_t current_video_input = 0x00000000; // HDMI/SDI.
410 uint32_t current_audio_input = 0x00000000; // Embedded.
411 PixelFormat current_pixel_format = PixelFormat_8BitYCbCr;
413 bool disconnected = false;