1 // A fake capture device that sends single-color frames at a given rate.
2 // Mostly useful for testing themes without actually hooking up capture devices.
4 #include "bmusb/fake_capture.h"
15 #include <immintrin.h>
20 #include "bmusb/bmusb.h"
22 #define FRAME_SIZE (8 << 20) // 8 MB.
24 // Pure-color inputs: Red, green, blue, white.
26 constexpr uint8_t ys[NUM_COLORS] = { 81, 145, 41, 235 };
27 constexpr uint8_t cbs[NUM_COLORS] = { 90, 54, 240, 128 };
28 constexpr uint8_t crs[NUM_COLORS] = { 240, 34, 110, 128 };
31 using namespace std::chrono;
36 // We don't bother with multiversioning for this, because SSE2
37 // is on by default for all 64-bit compiles, which is really
38 // the target user segment here.
40 void memset2(uint8_t *s, const uint8_t c[2], size_t n)
44 const uint8_t c_expanded[16] = {
45 c[0], c[1], c[0], c[1], c[0], c[1], c[0], c[1],
46 c[0], c[1], c[0], c[1], c[0], c[1], c[0], c[1]
48 __m128i cc = *(__m128i *)c_expanded;
49 __m128i *out = (__m128i *)s;
51 for ( ; i < (n & ~15); i += 16) {
52 _mm_storeu_si128(out++, cc);
53 _mm_storeu_si128(out++, cc);
64 void memset4(uint8_t *s, const uint8_t c[4], size_t n)
68 const uint8_t c_expanded[16] = {
69 c[0], c[1], c[2], c[3], c[0], c[1], c[2], c[3],
70 c[0], c[1], c[2], c[3], c[0], c[1], c[2], c[3]
72 __m128i cc = *(__m128i *)c_expanded;
73 __m128i *out = (__m128i *)s;
75 for ( ; i < (n & ~7); i += 8) {
76 _mm_storeu_si128(out++, cc);
77 _mm_storeu_si128(out++, cc);
92 FakeCapture::FakeCapture(unsigned width, unsigned height, unsigned fps, unsigned audio_sample_frequency, int card_index, bool has_audio)
93 : width(width), height(height), fps(fps), audio_sample_frequency(audio_sample_frequency), card_index(card_index)
96 snprintf(buf, sizeof(buf), "Fake card %d", card_index + 1);
99 y = ys[card_index % NUM_COLORS];
100 cb = cbs[card_index % NUM_COLORS];
101 cr = crs[card_index % NUM_COLORS];
104 audio_ref_level = pow(10.0f, -23.0f / 20.0f) * (1u << 31); // -23 dBFS (EBU R128 level).
106 float freq = 440.0 * pow(2.0, card_index / 12.0);
107 sincosf(2 * M_PI * freq / audio_sample_frequency, &audio_sin, &audio_cos);
108 audio_real = audio_ref_level;
113 FakeCapture::~FakeCapture()
115 if (has_dequeue_callbacks) {
116 dequeue_cleanup_callback();
120 void FakeCapture::configure_card()
122 if (video_frame_allocator == nullptr) {
123 owned_video_frame_allocator.reset(new MallocFrameAllocator(FRAME_SIZE, NUM_QUEUED_VIDEO_FRAMES));
124 set_video_frame_allocator(owned_video_frame_allocator.get());
126 if (audio_frame_allocator == nullptr) {
127 owned_audio_frame_allocator.reset(new MallocFrameAllocator(65536, NUM_QUEUED_AUDIO_FRAMES));
128 set_audio_frame_allocator(owned_audio_frame_allocator.get());
132 void FakeCapture::start_bm_capture()
134 producer_thread_should_quit = false;
135 producer_thread = thread(&FakeCapture::producer_thread_func, this);
138 void FakeCapture::stop_dequeue_thread()
140 producer_thread_should_quit = true;
141 producer_thread.join();
144 std::map<uint32_t, VideoMode> FakeCapture::get_available_video_modes() const
149 snprintf(buf, sizeof(buf), "%ux%u", width, height);
152 mode.autodetect = false;
154 mode.height = height;
155 mode.frame_rate_num = fps;
156 mode.frame_rate_den = 1;
157 mode.interlaced = false;
159 return {{ 0, mode }};
162 std::map<uint32_t, std::string> FakeCapture::get_available_video_inputs() const
164 return {{ 0, "Fake video input (single color)" }};
167 std::map<uint32_t, std::string> FakeCapture::get_available_audio_inputs() const
169 return {{ 0, "Fake audio input (silence)" }};
172 void FakeCapture::set_video_mode(uint32_t video_mode_id)
174 assert(video_mode_id == 0);
177 void FakeCapture::set_video_input(uint32_t video_input_id)
179 assert(video_input_id == 0);
182 void FakeCapture::set_audio_input(uint32_t audio_input_id)
184 assert(audio_input_id == 0);
189 void add_time(double t, timespec *ts)
191 ts->tv_nsec += lrint(t * 1e9);
192 ts->tv_sec += ts->tv_nsec / 1000000000;
193 ts->tv_nsec %= 1000000000;
196 bool timespec_less_than(const timespec &a, const timespec &b)
198 return make_pair(a.tv_sec, a.tv_nsec) < make_pair(b.tv_sec, b.tv_nsec);
203 void FakeCapture::producer_thread_func()
205 char thread_name[16];
206 snprintf(thread_name, sizeof(thread_name), "FakeCapture_%d", card_index);
207 pthread_setname_np(pthread_self(), thread_name);
209 uint16_t timecode = 0;
211 if (has_dequeue_callbacks) {
212 dequeue_init_callback();
216 clock_gettime(CLOCK_MONOTONIC, &next_frame);
217 add_time(1.0 / fps, &next_frame);
219 while (!producer_thread_should_quit) {
221 clock_gettime(CLOCK_MONOTONIC, &now);
223 if (timespec_less_than(now, next_frame)) {
224 // Wait until the next frame.
225 if (clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME,
226 &next_frame, nullptr) == -1) {
227 if (errno == EINTR) continue; // Re-check the flag and then sleep again.
228 perror("clock_nanosleep");
232 // We've seemingly missed a frame. If we're more than one second behind,
233 // reset the timer; otherwise, just keep going.
234 timespec limit = next_frame;
236 if (!timespec_less_than(now, limit)) {
237 fprintf(stderr, "More than one second of missed fake frames; resetting clock.\n");
241 steady_clock::time_point timestamp = steady_clock::now();
243 // Figure out when the next frame is to be, then compute the current one.
244 add_time(1.0 / fps, &next_frame);
246 VideoFormat video_format;
247 video_format.width = width;
248 video_format.height = height;
249 video_format.frame_rate_nom = fps;
250 video_format.frame_rate_den = 1;
251 video_format.has_signal = true;
252 video_format.is_connected = false;
254 FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
255 if (video_frame.data != nullptr) {
256 assert(video_frame.size >= width * height * 2);
257 if (video_frame.interleaved) {
258 uint8_t cbcr[] = { cb, cr };
259 memset2(video_frame.data, cbcr, width * height / 2);
260 memset(video_frame.data2, y, width * height);
262 uint8_t ycbcr[] = { y, cb, y, cr };
263 memset4(video_frame.data, ycbcr, width * height / 2);
265 video_frame.len = width * height * 2;
266 video_frame.received_timestamp = timestamp;
269 AudioFormat audio_format;
270 audio_format.bits_per_sample = 32;
271 audio_format.num_channels = 8;
273 FrameAllocator::Frame audio_frame = audio_frame_allocator->alloc_frame();
274 if (audio_frame.data != nullptr) {
275 const unsigned num_stereo_samples = audio_sample_frequency / fps;
276 assert(audio_frame.size >= audio_format.num_channels * sizeof(int32_t) * num_stereo_samples);
277 audio_frame.len = audio_format.num_channels * sizeof(int32_t) * num_stereo_samples;
278 audio_frame.received_timestamp = timestamp;
280 if (audio_sin == 0.0f) {
282 memset(audio_frame.data, 0, audio_frame.len);
284 make_tone((int32_t *)audio_frame.data, num_stereo_samples, audio_format.num_channels);
288 frame_callback(timecode++,
289 video_frame, 0, video_format,
290 audio_frame, 0, audio_format);
292 if (has_dequeue_callbacks) {
293 dequeue_cleanup_callback();
297 void FakeCapture::make_tone(int32_t *out, unsigned num_stereo_samples, unsigned num_channels)
300 float r = audio_real, i = audio_imag;
301 for (unsigned sample_num = 0; sample_num < num_stereo_samples; ++sample_num) {
302 int32_t s = lrintf(r);
303 for (unsigned i = 0; i < num_channels; ++i) {
307 // Rotate the phaser by one sample.
308 float new_r = r * audio_cos - i * audio_sin;
309 float new_i = r * audio_sin + i * audio_cos;
314 // Periodically renormalize to counteract precision issues.
315 double corr = audio_ref_level / hypot(r, i);
316 audio_real = r * corr;
317 audio_imag = i * corr;