7 #include <condition_variable>
21 // An interface for frame allocators; if you do not specify one
22 // (using set_video_frame_allocator), a default one that pre-allocates
23 // a freelist of eight frames using new[] will be used. Specifying
24 // your own can be useful if you have special demands for where you want the
25 // frame to end up and don't want to spend the extra copy to get it there, for
26 // instance GPU memory.
27 class FrameAllocator {
30 uint8_t *data = nullptr;
31 uint8_t *data2 = nullptr; // Only if interleaved == true.
32 size_t len = 0; // Number of bytes we actually have.
33 size_t size = 0; // Number of bytes we have room for.
35 void *userdata = nullptr;
36 FrameAllocator *owner = nullptr;
38 // If set to true, every other byte will go to data and to data2.
39 // If so, <len> and <size> are still about the number of total bytes
40 // so if size == 1024, there's 512 bytes in data and 512 in data2.
41 bool interleaved = false;
44 virtual ~FrameAllocator();
46 // Request a video frame. Note that this is called from the
47 // USB thread, which runs with realtime priority and is
48 // very sensitive to delays. Thus, you should not do anything
49 // here that might sleep, including calling malloc().
50 // (Taking a mutex is borderline.)
52 // The Frame object will be given to the frame callback,
53 // which is responsible for releasing the video frame back
54 // once it is usable for new frames (ie., it will no longer
55 // be read from). You can use the "userdata" pointer for
56 // whatever you want to identify this frame if you need to.
58 // Returning a Frame with data==nullptr is allowed;
59 // if so, the frame in progress will be dropped.
60 virtual Frame alloc_frame() = 0;
62 virtual void release_frame(Frame frame) = 0;
65 // Audio is more important than video, and also much cheaper.
66 // By having many more audio frames available, hopefully if something
67 // starts to drop, we'll have CPU load go down (from not having to
68 // process as much video) before we have to drop audio.
69 #define NUM_QUEUED_VIDEO_FRAMES 16
70 #define NUM_QUEUED_AUDIO_FRAMES 64
72 class MallocFrameAllocator : public FrameAllocator {
74 MallocFrameAllocator(size_t frame_size, size_t num_queued_frames);
75 Frame alloc_frame() override;
76 void release_frame(Frame frame) override;
81 std::mutex freelist_mutex;
82 std::stack<std::unique_ptr<uint8_t[]>> freelist; // All of size <frame_size>.
85 // Represents an input mode you can tune a card to.
88 bool autodetect = false; // If true, all the remaining fields are irrelevant.
89 unsigned width = 0, height = 0;
90 unsigned frame_rate_num = 0, frame_rate_den = 0;
91 bool interlaced = false;
94 // Represents the format of an actual frame coming in.
95 // Note: Frame rate is _frame_ rate, not field rate. So 1080i60 gets 30/1, _not_ 60/1.
96 // "second_field_start" is only valid for interlaced modes; it signifies
97 // how many lines from the very top of the frame there are before the second field
98 // starts (so it will always be >= height/2 + extra_lines_top).
100 uint16_t id = 0; // For debugging/logging only.
101 unsigned width = 0, height = 0, second_field_start = 0;
102 unsigned extra_lines_top = 0, extra_lines_bottom = 0;
103 unsigned frame_rate_nom = 0, frame_rate_den = 0;
104 bool interlaced = false;
105 bool has_signal = false;
106 bool is_connected = true; // If false, then has_signal makes no sense.
110 uint16_t id = 0; // For debugging/logging only.
111 unsigned bits_per_sample = 0;
112 unsigned num_channels = 0;
115 typedef std::function<void(uint16_t timecode,
116 FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
117 FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)>
120 typedef std::function<void(libusb_device *dev)> card_connected_callback_t;
121 typedef std::function<void()> card_disconnected_callback_t;
123 class CaptureInterface {
125 virtual ~CaptureInterface() {}
127 virtual std::map<uint32_t, VideoMode> get_available_video_modes() const = 0;
128 virtual uint32_t get_current_video_mode() const = 0;
129 virtual void set_video_mode(uint32_t video_mode_id) = 0;
131 virtual std::map<uint32_t, std::string> get_available_video_inputs() const = 0;
132 virtual void set_video_input(uint32_t video_input_id) = 0;
133 virtual uint32_t get_current_video_input() const = 0;
135 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const = 0;
136 virtual void set_audio_input(uint32_t audio_input_id) = 0;
137 virtual uint32_t get_current_audio_input() const = 0;
139 // Does not take ownership.
140 virtual void set_video_frame_allocator(FrameAllocator *allocator) = 0;
142 virtual FrameAllocator *get_video_frame_allocator() = 0;
144 // Does not take ownership.
145 virtual void set_audio_frame_allocator(FrameAllocator *allocator) = 0;
147 virtual FrameAllocator *get_audio_frame_allocator() = 0;
149 virtual void set_frame_callback(frame_callback_t callback) = 0;
151 // Needs to be run before configure_card().
152 virtual void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) = 0;
154 // Only valid after configure_card().
155 virtual std::string get_description() const = 0;
157 virtual void configure_card() = 0;
159 virtual void start_bm_capture() = 0;
161 virtual void stop_dequeue_thread() = 0;
163 // If a card is disconnected, it cannot come back; you should call stop_dequeue_thread()
165 virtual bool get_disconnected() const = 0;
168 // The actual capturing class, representing capture from a single card.
169 class BMUSBCapture : public CaptureInterface {
171 BMUSBCapture(int card_index, libusb_device *dev = nullptr)
172 : card_index(card_index), dev(dev)
178 std::map<uint32_t, VideoMode> get_available_video_modes() const override;
179 uint32_t get_current_video_mode() const override;
180 void set_video_mode(uint32_t video_mode_id) override;
182 virtual std::map<uint32_t, std::string> get_available_video_inputs() const override;
183 virtual void set_video_input(uint32_t video_input_id) override;
184 virtual uint32_t get_current_video_input() const override { return current_video_input; }
186 virtual std::map<uint32_t, std::string> get_available_audio_inputs() const override;
187 virtual void set_audio_input(uint32_t audio_input_id) override;
188 virtual uint32_t get_current_audio_input() const override { return current_audio_input; }
190 // Does not take ownership.
191 void set_video_frame_allocator(FrameAllocator *allocator) override
193 video_frame_allocator = allocator;
194 if (owned_video_frame_allocator.get() != allocator) {
195 owned_video_frame_allocator.reset();
199 FrameAllocator *get_video_frame_allocator() override
201 return video_frame_allocator;
204 // Does not take ownership.
205 void set_audio_frame_allocator(FrameAllocator *allocator) override
207 audio_frame_allocator = allocator;
208 if (owned_audio_frame_allocator.get() != allocator) {
209 owned_audio_frame_allocator.reset();
213 FrameAllocator *get_audio_frame_allocator() override
215 return audio_frame_allocator;
218 void set_frame_callback(frame_callback_t callback) override
220 frame_callback = callback;
223 // Needs to be run before configure_card().
224 void set_dequeue_thread_callbacks(std::function<void()> init, std::function<void()> cleanup) override
226 dequeue_init_callback = init;
227 dequeue_cleanup_callback = cleanup;
228 has_dequeue_callbacks = true;
231 // Only valid after configure_card().
232 std::string get_description() const override {
236 void configure_card() override;
237 void start_bm_capture() override;
238 void stop_dequeue_thread() override;
239 bool get_disconnected() const override { return disconnected; }
241 // TODO: It's rather messy to have these outside the interface.
242 static void start_bm_thread();
243 static void stop_bm_thread();
245 // Hotplug event (for devices being inserted between start_bm_thread()
246 // and stop_bm_thread()); entirely optional, but must be set before
247 // start_bm_capture(). Note that your callback should do as little work
248 // as possible, since the callback comes from the main USB handling
249 // thread, which is very time-sensitive.
251 // The callback function transfers ownership. If you don't want to hold
252 // on to the device given to you in the callback, you need to call
253 // libusb_unref_device().
254 static void set_card_connected_callback(card_connected_callback_t callback)
256 card_connected_callback = callback;
259 // Similar to set_card_connected_callback(), with the same caveats.
260 // (Note that this is set per-card and not global, as it is logically
261 // connected to an existing BMUSBCapture object.)
262 void set_card_disconnected_callback(card_disconnected_callback_t callback)
264 card_disconnected_callback = callback;
271 FrameAllocator::Frame frame;
274 void start_new_audio_block(const uint8_t *start);
275 void start_new_frame(const uint8_t *start);
277 void queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame, std::deque<QueuedFrame> *q);
278 void dequeue_thread_func();
280 static void usb_thread_func();
281 static void cb_xfr(struct libusb_transfer *xfr);
282 static int cb_hotplug(libusb_context *ctx, libusb_device *dev, libusb_hotplug_event event, void *user_data);
284 void update_capture_mode();
286 std::string description;
288 FrameAllocator::Frame current_video_frame;
289 FrameAllocator::Frame current_audio_frame;
291 std::mutex queue_lock;
292 std::condition_variable queues_not_empty;
293 std::deque<QueuedFrame> pending_video_frames;
294 std::deque<QueuedFrame> pending_audio_frames;
296 FrameAllocator *video_frame_allocator = nullptr;
297 FrameAllocator *audio_frame_allocator = nullptr;
298 std::unique_ptr<FrameAllocator> owned_video_frame_allocator;
299 std::unique_ptr<FrameAllocator> owned_audio_frame_allocator;
300 frame_callback_t frame_callback = nullptr;
301 static card_connected_callback_t card_connected_callback;
302 card_disconnected_callback_t card_disconnected_callback = nullptr;
304 std::thread dequeue_thread;
305 std::atomic<bool> dequeue_thread_should_quit;
306 bool has_dequeue_callbacks = false;
307 std::function<void()> dequeue_init_callback = nullptr;
308 std::function<void()> dequeue_cleanup_callback = nullptr;
310 int current_register = 0;
312 static constexpr int NUM_BMUSB_REGISTERS = 60;
313 uint8_t register_file[NUM_BMUSB_REGISTERS];
315 // If <dev> is nullptr, will choose device number <card_index> from the list
316 // of available devices on the system. <dev> is not used after configure_card()
317 // (it will be unref-ed).
319 libusb_device *dev = nullptr;
321 std::vector<libusb_transfer *> iso_xfrs;
322 int assumed_frame_width = 1280;
324 libusb_device_handle *devh = nullptr;
325 uint32_t current_video_input = 0x00000000; // HDMI/SDI.
326 uint32_t current_audio_input = 0x00000000; // Embedded.
328 bool disconnected = false;