7 #include <condition_variable>
19 // An interface for frame allocators; if you do not specify one
20 // (using set_video_frame_allocator), a default one that pre-allocates
21 // a freelist of eight frames using new[] will be used. Specifying
22 // your own can be useful if you have special demands for where you want the
23 // frame to end up and don't want to spend the extra copy to get it there, for
24 // instance GPU memory.
25 class FrameAllocator {
28 uint8_t *data = nullptr;
29 uint8_t *data2 = nullptr; // Only if interleaved == true.
30 size_t len = 0; // Number of bytes we actually have.
31 size_t size = 0; // Number of bytes we have room for.
33 void *userdata = nullptr;
34 FrameAllocator *owner = nullptr;
36 // If set to true, every other byte will go to data and to data2.
37 // If so, <len> and <size> are still about the number of total bytes
38 // so if size == 1024, there's 512 bytes in data and 512 in data2.
39 bool interleaved = false;
42 virtual ~FrameAllocator();
44 // Request a video frame. Note that this is called from the
45 // USB thread, which runs with realtime priority and is
46 // very sensitive to delays. Thus, you should not do anything
47 // here that might sleep, including calling malloc().
48 // (Taking a mutex is borderline.)
50 // The Frame object will be given to the frame callback,
51 // which is responsible for releasing the video frame back
52 // once it is usable for new frames (ie., it will no longer
53 // be read from). You can use the "userdata" pointer for
54 // whatever you want to identify this frame if you need to.
56 // Returning a Frame with data==nullptr is allowed;
57 // if so, the frame in progress will be dropped.
58 virtual Frame alloc_frame() = 0;
60 virtual void release_frame(Frame frame) = 0;
63 // Audio is more important than video, and also much cheaper.
64 // By having many more audio frames available, hopefully if something
65 // starts to drop, we'll have CPU load go down (from not having to
66 // process as much video) before we have to drop audio.
67 #define NUM_QUEUED_VIDEO_FRAMES 16
68 #define NUM_QUEUED_AUDIO_FRAMES 64
70 class MallocFrameAllocator : public FrameAllocator {
72 MallocFrameAllocator(size_t frame_size, size_t num_queued_frames);
73 Frame alloc_frame() override;
74 void release_frame(Frame frame) override;
79 std::mutex freelist_mutex;
80 std::stack<std::unique_ptr<uint8_t[]>> freelist; // All of size <frame_size>.
83 // Represents an input mode you can tune a card to.
86 bool autodetect = false; // If true, all the remaining fields are irrelevant.
87 unsigned width = 0, height = 0;
88 unsigned frame_rate_num = 0, frame_rate_den = 0;
89 bool interlaced = false;
92 // Represents the format of an actual frame coming in.
93 // Note: Frame rate is _frame_ rate, not field rate. So 1080i60 gets 30/1, _not_ 60/1.
94 // "second_field_start" is only valid for interlaced modes; it signifies
95 // how many lines from the very top of the frame there are before the second field
96 // starts (so it will always be >= height/2 + extra_lines_top).
98 uint16_t id = 0; // For debugging/logging only.
99 unsigned width = 0, height = 0, second_field_start = 0;
100 unsigned extra_lines_top = 0, extra_lines_bottom = 0;
101 unsigned frame_rate_nom = 0, frame_rate_den = 0;
102 bool interlaced = false;
103 bool has_signal = false;
104 bool is_connected = true; // If false, then has_signal makes no sense.
108 uint16_t id = 0; // For debugging/logging only.
109 unsigned bits_per_sample = 0;
110 unsigned num_channels = 0;
113 typedef std::function<void(uint16_t timecode,
114 FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
115 FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)>
118 typedef std::function<void(libusb_device *dev)> card_connected_callback_t;
119 typedef std::function<void()> card_disconnected_callback_t;
121 class CaptureInterface {
123 virtual ~CaptureInterface() {}
125 virtual std::map<uint32_t, VideoMode> get_available_video_modes() const = 0;
126 virtual uint32_t get_current_video_mode() const = 0;
127 virtual void set_video_mode(uint32_t video_mode_id) = 0;
129 virtual std::map<uint32_t, std::string> get_available_video_inputs() const = 0;
130 virtual void set_video_input(uint32_t video_input_id) = 0;
131 virtual uint32_t get_current_video_input() const = 0;
133 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const = 0;
134 virtual void set_audio_input(uint32_t audio_input_id) = 0;
135 virtual uint32_t get_current_audio_input() const = 0;
137 // Does not take ownership.
138 virtual void set_video_frame_allocator(FrameAllocator *allocator) = 0;
140 virtual FrameAllocator *get_video_frame_allocator() = 0;
142 // Does not take ownership.
143 virtual void set_audio_frame_allocator(FrameAllocator *allocator) = 0;
145 virtual FrameAllocator *get_audio_frame_allocator() = 0;
147 virtual void set_frame_callback(frame_callback_t callback) = 0;
149 // Needs to be run before configure_card().
150 virtual void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) = 0;
152 // Only valid after configure_card().
153 virtual std::string get_description() const = 0;
155 virtual void configure_card() = 0;
157 virtual void start_bm_capture() = 0;
159 virtual void stop_dequeue_thread() = 0;
161 // If a card is disconnected, it cannot come back; you should call stop_dequeue_thread()
163 virtual bool get_disconnected() const = 0;
166 // The actual capturing class, representing capture from a single card.
167 class BMUSBCapture : public CaptureInterface {
169 BMUSBCapture(int card_index, libusb_device *dev = nullptr)
170 : card_index(card_index), dev(dev)
176 std::map<uint32_t, VideoMode> get_available_video_modes() const override;
177 uint32_t get_current_video_mode() const override;
178 void set_video_mode(uint32_t video_mode_id) override;
180 virtual std::map<uint32_t, std::string> get_available_video_inputs() const override;
181 virtual void set_video_input(uint32_t video_input_id) override;
182 virtual uint32_t get_current_video_input() const override { return current_video_input; }
184 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const override;
185 virtual void set_audio_input(uint32_t audio_input_id) override;
186 virtual uint32_t get_current_audio_input() const override { return current_audio_input; }
188 // Does not take ownership.
189 void set_video_frame_allocator(FrameAllocator *allocator) override
191 video_frame_allocator = allocator;
192 if (owned_video_frame_allocator.get() != allocator) {
193 owned_video_frame_allocator.reset();
197 FrameAllocator *get_video_frame_allocator() override
199 return video_frame_allocator;
202 // Does not take ownership.
203 void set_audio_frame_allocator(FrameAllocator *allocator) override
205 audio_frame_allocator = allocator;
206 if (owned_audio_frame_allocator.get() != allocator) {
207 owned_audio_frame_allocator.reset();
211 FrameAllocator *get_audio_frame_allocator() override
213 return audio_frame_allocator;
216 void set_frame_callback(frame_callback_t callback) override
218 frame_callback = callback;
221 // Needs to be run before configure_card().
222 void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) override
224 dequeue_init_callback = init;
225 dequeue_cleanup_callback = cleanup;
226 has_dequeue_callbacks = true;
229 // Only valid after configure_card().
230 std::string get_description() const override {
234 void configure_card() override;
235 void start_bm_capture() override;
236 void stop_dequeue_thread() override;
237 bool get_disconnected() const override { return disconnected; }
239 // TODO: It's rather messy to have these outside the interface.
240 static void start_bm_thread();
241 static void stop_bm_thread();
243 // Hotplug event (for devices being inserted between start_bm_thread()
244 // and stop_bm_thread()); entirely optional, but must be set before
245 // start_bm_capture(). Note that your callback should do as little work
246 // as possible, since the callback comes from the main USB handling
247 // thread, which is very time-sensitive.
249 // The callback function transfers ownership. If you don't want to hold
250 // on to the device given to you in the callback, you need to call
251 // libusb_unref_device().
252 static void set_card_connected_callback(card_connected_callback_t callback)
254 card_connected_callback = callback;
257 // Similar to set_card_connected_callback(), with the same caveats.
258 // (Note that this is set per-card and not global, as it is logically
259 // connected to an existing BMUSBCapture object.)
260 void set_card_disconnected_callback(card_disconnected_callback_t callback)
262 card_disconnected_callback = callback;
269 FrameAllocator::Frame frame;
272 void start_new_audio_block(const uint8_t *start);
273 void start_new_frame(const uint8_t *start);
275 void queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame, std::deque<QueuedFrame> *q);
276 void dequeue_thread_func();
278 static void usb_thread_func();
279 static void cb_xfr(struct libusb_transfer *xfr);
280 static int cb_hotplug(libusb_context *ctx, libusb_device *dev, libusb_hotplug_event event, void *user_data);
282 void update_capture_mode();
284 std::string description;
286 FrameAllocator::Frame current_video_frame;
287 FrameAllocator::Frame current_audio_frame;
289 std::mutex queue_lock;
290 std::condition_variable queues_not_empty;
291 std::deque<QueuedFrame> pending_video_frames;
292 std::deque<QueuedFrame> pending_audio_frames;
294 FrameAllocator *video_frame_allocator = nullptr;
295 FrameAllocator *audio_frame_allocator = nullptr;
296 std::unique_ptr<FrameAllocator> owned_video_frame_allocator;
297 std::unique_ptr<FrameAllocator> owned_audio_frame_allocator;
298 frame_callback_t frame_callback = nullptr;
299 static card_connected_callback_t card_connected_callback;
300 card_disconnected_callback_t card_disconnected_callback = nullptr;
302 std::thread dequeue_thread;
303 std::atomic<bool> dequeue_thread_should_quit;
304 bool has_dequeue_callbacks = false;
305 std::function<void()> dequeue_init_callback = nullptr;
306 std::function<void()> dequeue_cleanup_callback = nullptr;
308 int current_register = 0;
310 static constexpr int NUM_BMUSB_REGISTERS = 60;
311 uint8_t register_file[NUM_BMUSB_REGISTERS];
313 // If <dev> is nullptr, will choose device number <card_index> from the list
314 // of available devices on the system. <dev> is not used after configure_card()
315 // (it will be unref-ed).
317 libusb_device *dev = nullptr;
319 std::vector<libusb_transfer *> iso_xfrs;
320 int assumed_frame_width = 1280;
322 libusb_device_handle *devh = nullptr;
323 uint32_t current_video_input = 0x00000000; // HDMI/SDI.
324 uint32_t current_audio_input = 0x00000000; // Embedded.
326 bool disconnected = false;