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;
129 unsigned sample_rate = 48000;
133 // 8-bit 4:2:2 in the standard Cb Y Cr Y order (UYVY).
134 // This is the default.
135 PixelFormat_8BitYCbCr,
137 // 10-bit 4:2:2 in v210 order. Six pixels (six Y', three Cb,
138 // three Cr) are packed into four 32-bit little-endian ints
139 // in the following pattern (see e.g. the DeckLink documentation
149 // If you read in RGB order and ignore the unused top bits,
150 // this is essentially Cb Y Cr Y order, just like UYVY is.
152 // Note that unlike true v210, there is no guarantee about
153 // 128-byte line alignment (or lack thereof); you should check
154 // the stride member of VideoFormat.
155 PixelFormat_10BitYCbCr,
157 // 8-bit 4:4:4:4 BGRA (in that order). bmusb itself doesn't
158 // produce this, but it is useful to represent e.g. synthetic inputs.
159 PixelFormat_8BitBGRA,
161 // 8-bit 4:2:0, 4:2:2, 4:4:4 or really anything else, planar
162 // (ie., first all Y', then all Cb, then all Cr). bmusb doesn't
163 // produce this, nor does it specify a mechanism to describe
164 // the precise details of the format.
165 PixelFormat_8BitYCbCrPlanar,
167 // These exist only so that the type is guaranteed wide enough
168 // to contain values up to 127. CaptureInterface instances
169 // are free to use them as they see fit for private uses.
170 PixelFormat_Unused100 = 100,
171 PixelFormat_Unused127 = 127
174 typedef std::function<void(uint16_t timecode,
175 FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
176 FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)>
179 typedef std::function<void(libusb_device *dev)> card_connected_callback_t;
180 typedef std::function<void()> card_disconnected_callback_t;
182 class CaptureInterface {
184 virtual ~CaptureInterface() {}
186 virtual std::map<uint32_t, VideoMode> get_available_video_modes() const = 0;
187 virtual uint32_t get_current_video_mode() const = 0;
188 virtual void set_video_mode(uint32_t video_mode_id) = 0;
190 // TODO: Add a way to query this based on mode?
191 virtual std::set<PixelFormat> get_available_pixel_formats() const = 0;
192 virtual void set_pixel_format(PixelFormat pixel_format) = 0;
193 virtual PixelFormat get_current_pixel_format() const = 0;
195 virtual std::map<uint32_t, std::string> get_available_video_inputs() const = 0;
196 virtual void set_video_input(uint32_t video_input_id) = 0;
197 virtual uint32_t get_current_video_input() const = 0;
199 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const = 0;
200 virtual void set_audio_input(uint32_t audio_input_id) = 0;
201 virtual uint32_t get_current_audio_input() const = 0;
203 // Does not take ownership.
204 virtual void set_video_frame_allocator(FrameAllocator *allocator) = 0;
206 virtual FrameAllocator *get_video_frame_allocator() = 0;
208 // Does not take ownership.
209 virtual void set_audio_frame_allocator(FrameAllocator *allocator) = 0;
211 virtual FrameAllocator *get_audio_frame_allocator() = 0;
213 virtual void set_frame_callback(frame_callback_t callback) = 0;
215 // Needs to be run before configure_card().
216 virtual void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) = 0;
218 // Only valid after configure_card().
219 virtual std::string get_description() const = 0;
221 virtual void configure_card() = 0;
223 virtual void start_bm_capture() = 0;
225 virtual void stop_dequeue_thread() = 0;
227 // If a card is disconnected, it cannot come back; you should call stop_dequeue_thread()
229 virtual bool get_disconnected() const = 0;
232 // The actual capturing class, representing capture from a single card.
233 class BMUSBCapture : public CaptureInterface {
235 BMUSBCapture(int card_index, libusb_device *dev = nullptr)
236 : card_index(card_index), dev(dev)
242 // Note: Cards could be unplugged and replugged between this call and
243 // actually opening the card (in configure_card()).
244 static unsigned num_cards();
246 std::set<PixelFormat> get_available_pixel_formats() const override
248 return std::set<PixelFormat>{ PixelFormat_8BitYCbCr, PixelFormat_10BitYCbCr };
251 void set_pixel_format(PixelFormat pixel_format) override;
253 PixelFormat get_current_pixel_format() const
255 return current_pixel_format;
258 std::map<uint32_t, VideoMode> get_available_video_modes() const override;
259 uint32_t get_current_video_mode() const override;
260 void set_video_mode(uint32_t video_mode_id) override;
262 virtual std::map<uint32_t, std::string> get_available_video_inputs() const override;
263 virtual void set_video_input(uint32_t video_input_id) override;
264 virtual uint32_t get_current_video_input() const override { return current_video_input; }
266 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const override;
267 virtual void set_audio_input(uint32_t audio_input_id) override;
268 virtual uint32_t get_current_audio_input() const override { return current_audio_input; }
270 // Does not take ownership.
271 void set_video_frame_allocator(FrameAllocator *allocator) override
273 video_frame_allocator = allocator;
274 if (owned_video_frame_allocator.get() != allocator) {
275 owned_video_frame_allocator.reset();
279 FrameAllocator *get_video_frame_allocator() override
281 return video_frame_allocator;
284 // Does not take ownership.
285 void set_audio_frame_allocator(FrameAllocator *allocator) override
287 audio_frame_allocator = allocator;
288 if (owned_audio_frame_allocator.get() != allocator) {
289 owned_audio_frame_allocator.reset();
293 FrameAllocator *get_audio_frame_allocator() override
295 return audio_frame_allocator;
298 void set_frame_callback(frame_callback_t callback) override
300 frame_callback = callback;
303 // Needs to be run before configure_card().
304 void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) override
306 dequeue_init_callback = init;
307 dequeue_cleanup_callback = cleanup;
308 has_dequeue_callbacks = true;
311 // Only valid after configure_card().
312 std::string get_description() const override {
316 void configure_card() override;
317 void start_bm_capture() override;
318 void stop_dequeue_thread() override;
319 bool get_disconnected() const override { return disconnected; }
321 // TODO: It's rather messy to have these outside the interface.
322 static void start_bm_thread();
323 static void stop_bm_thread();
325 // Hotplug event (for devices being inserted between start_bm_thread()
326 // and stop_bm_thread()); entirely optional, but must be set before
327 // start_bm_capture(). Note that your callback should do as little work
328 // as possible, since the callback comes from the main USB handling
329 // thread, which is very time-sensitive.
331 // The callback function transfers ownership. If you don't want to hold
332 // on to the device given to you in the callback, you need to call
333 // libusb_unref_device().
334 static void set_card_connected_callback(card_connected_callback_t callback,
335 bool hotplug_existing_devices_arg = false)
337 card_connected_callback = callback;
338 hotplug_existing_devices = hotplug_existing_devices_arg;
341 // Similar to set_card_connected_callback(), with the same caveats.
342 // (Note that this is set per-card and not global, as it is logically
343 // connected to an existing BMUSBCapture object.)
344 void set_card_disconnected_callback(card_disconnected_callback_t callback)
346 card_disconnected_callback = callback;
353 FrameAllocator::Frame frame;
356 void start_new_audio_block(const uint8_t *start);
357 void start_new_frame(const uint8_t *start);
359 void queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame, std::deque<QueuedFrame> *q);
360 void dequeue_thread_func();
362 static void usb_thread_func();
363 static void cb_xfr(struct libusb_transfer *xfr);
364 static int cb_hotplug(libusb_context *ctx, libusb_device *dev, libusb_hotplug_event event, void *user_data);
366 void update_capture_mode();
368 std::string description;
370 FrameAllocator::Frame current_video_frame;
371 FrameAllocator::Frame current_audio_frame;
373 std::mutex queue_lock;
374 std::condition_variable queues_not_empty;
375 std::deque<QueuedFrame> pending_video_frames;
376 std::deque<QueuedFrame> pending_audio_frames;
378 FrameAllocator *video_frame_allocator = nullptr;
379 FrameAllocator *audio_frame_allocator = nullptr;
380 std::unique_ptr<FrameAllocator> owned_video_frame_allocator;
381 std::unique_ptr<FrameAllocator> owned_audio_frame_allocator;
382 frame_callback_t frame_callback = nullptr;
383 static card_connected_callback_t card_connected_callback;
384 static bool hotplug_existing_devices;
385 card_disconnected_callback_t card_disconnected_callback = nullptr;
387 std::thread dequeue_thread;
388 std::atomic<bool> dequeue_thread_should_quit;
389 bool has_dequeue_callbacks = false;
390 std::function<void()> dequeue_init_callback = nullptr;
391 std::function<void()> dequeue_cleanup_callback = nullptr;
393 int current_register = 0;
395 static constexpr int NUM_BMUSB_REGISTERS = 60;
396 uint8_t register_file[NUM_BMUSB_REGISTERS];
398 // If <dev> is nullptr, will choose device number <card_index> from the list
399 // of available devices on the system. <dev> is not used after configure_card()
400 // (it will be unref-ed).
402 libusb_device *dev = nullptr;
404 std::vector<libusb_transfer *> iso_xfrs;
405 int assumed_frame_width = 1280;
407 libusb_device_handle *devh = nullptr;
408 uint32_t current_video_input = 0x00000000; // HDMI/SDI.
409 uint32_t current_audio_input = 0x00000000; // Embedded.
410 PixelFormat current_pixel_format = PixelFormat_8BitYCbCr;
412 bool disconnected = false;