git.sesse.net Git - nageru/blob - nageru/mjpeg_encoder.cpp

   1 #include "mjpeg_encoder.h"
   2
   3 #include <assert.h>
   4 #include <jpeglib.h>
   5 #include <unistd.h>
   6 #if __SSE2__
   7 #include <immintrin.h>
   8 #endif
   9 #include <list>
  10
  11 extern "C" {
  12 #include <libavformat/avformat.h>
  13 }
  14
  15 #include "defs.h"
  16 #include "shared/ffmpeg_raii.h"
  17 #include "flags.h"
  18 #include "shared/httpd.h"
  19 #include "shared/memcpy_interleaved.h"
  20 #include "shared/metrics.h"
  21 #include "pbo_frame_allocator.h"
  22 #include "shared/timebase.h"
  23 #include "shared/va_display.h"
  24
  25 #include <movit/colorspace_conversion_effect.h>
  26
  27 #include <va/va.h>
  28 #include <va/va_drm.h>
  29 #include <va/va_x11.h>
  30
  31 using namespace Eigen;
  32 using namespace bmusb;
  33 using namespace movit;
  34 using namespace std;
  35
  36 static VAImageFormat uyvy_format, nv12_format;
  37
  38 extern void memcpy_with_pitch(uint8_t *dst, const uint8_t *src, size_t src_width, size_t dst_pitch, size_t height);
  39
  40 // The inverse of memcpy_interleaved(), with (slow) support for pitch.
  41 void interleave_with_pitch(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, size_t src_width, size_t dst_pitch, size_t height)
  42 {
  43 #if __SSE2__
  44         if (dst_pitch == src_width * 2 && (src_width * height) % 16 == 0) {
  45                 __m128i *dptr = reinterpret_cast<__m128i *>(dst);
  46                 const __m128i *sptr1 = reinterpret_cast<const __m128i *>(src1);
  47                 const __m128i *sptr2 = reinterpret_cast<const __m128i *>(src2);
  48                 for (size_t i = 0; i < src_width * height / 16; ++i) {
  49                         __m128i data1 = _mm_loadu_si128(sptr1++);
  50                         __m128i data2 = _mm_loadu_si128(sptr2++);
  51                         _mm_storeu_si128(dptr++, _mm_unpacklo_epi8(data1, data2));
  52                         _mm_storeu_si128(dptr++, _mm_unpackhi_epi8(data1, data2));
  53                 }
  54                 return;
  55         }
  56 #endif
  57
  58         for (size_t y = 0; y < height; ++y) {
  59                 uint8_t *dptr = dst + y * dst_pitch;
  60                 const uint8_t *sptr1 = src1 + y * src_width;
  61                 const uint8_t *sptr2 = src2 + y * src_width;
  62                 for (size_t x = 0; x < src_width; ++x) {
  63                         *dptr++ = *sptr1++;
  64                         *dptr++ = *sptr2++;
  65                 }
  66         }
  67 }
  68
  69 // From libjpeg (although it's of course identical between implementations).
  70 static const int jpeg_natural_order[DCTSIZE2] = {
  71          0,  1,  8, 16,  9,  2,  3, 10,
  72         17, 24, 32, 25, 18, 11,  4,  5,
  73         12, 19, 26, 33, 40, 48, 41, 34,
  74         27, 20, 13,  6,  7, 14, 21, 28,
  75         35, 42, 49, 56, 57, 50, 43, 36,
  76         29, 22, 15, 23, 30, 37, 44, 51,
  77         58, 59, 52, 45, 38, 31, 39, 46,
  78         53, 60, 61, 54, 47, 55, 62, 63,
  79 };
  80
  81 struct VectorDestinationManager {
  82         jpeg_destination_mgr pub;
  83         std::vector<uint8_t> dest;
  84
  85         VectorDestinationManager()
  86         {
  87                 pub.init_destination = init_destination_thunk;
  88                 pub.empty_output_buffer = empty_output_buffer_thunk;
  89                 pub.term_destination = term_destination_thunk;
  90         }
  91
  92         static void init_destination_thunk(j_compress_ptr ptr)
  93         {
  94                 ((VectorDestinationManager *)(ptr->dest))->init_destination();
  95         }
  96
  97         inline void init_destination()
  98         {
  99                 make_room(0);
 100         }
 101
 102         static boolean empty_output_buffer_thunk(j_compress_ptr ptr)
 103         {
 104                 return ((VectorDestinationManager *)(ptr->dest))->empty_output_buffer();
 105         }
 106
 107         inline bool empty_output_buffer()
 108         {
 109                 make_room(dest.size());  // Should ignore pub.free_in_buffer!
 110                 return true;
 111         }
 112
 113         inline void make_room(size_t bytes_used)
 114         {
 115                 dest.resize(bytes_used + 4096);
 116                 dest.resize(dest.capacity());
 117                 pub.next_output_byte = dest.data() + bytes_used;
 118                 pub.free_in_buffer = dest.size() - bytes_used;
 119         }
 120
 121         static void term_destination_thunk(j_compress_ptr ptr)
 122         {
 123                 ((VectorDestinationManager *)(ptr->dest))->term_destination();
 124         }
 125
 126         inline void term_destination()
 127         {
 128                 dest.resize(dest.size() - pub.free_in_buffer);
 129         }
 130 };
 131 static_assert(std::is_standard_layout<VectorDestinationManager>::value, "");
 132
 133 int MJPEGEncoder::write_packet2_thunk(void *opaque, uint8_t *buf, int buf_size, AVIODataMarkerType type, int64_t time)
 134 {
 135         WritePacket2Context *ctx = (WritePacket2Context *)opaque;
 136         return ctx->mjpeg_encoder->write_packet2(ctx->stream_id, buf, buf_size, type, time);
 137 }
 138
 139 int MJPEGEncoder::write_packet2(HTTPD::StreamID stream_id, uint8_t *buf, int buf_size, AVIODataMarkerType type, int64_t time)
 140 {
 141         string *mux_header = &streams[stream_id].mux_header;
 142         if (type == AVIO_DATA_MARKER_HEADER) {
 143                 mux_header->append((char *)buf, buf_size);
 144                 httpd->set_header(stream_id, *mux_header);
 145         } else {
 146                 httpd->add_data(stream_id, (char *)buf, buf_size, /*keyframe=*/true, AV_NOPTS_VALUE, AVRational{ AV_TIME_BASE, 1 });
 147         }
 148         return buf_size;
 149 }
 150
 151 namespace {
 152
 153 void add_video_stream(AVFormatContext *avctx)
 154 {
 155         AVStream *stream = avformat_new_stream(avctx, nullptr);
 156         if (stream == nullptr) {
 157                 fprintf(stderr, "avformat_new_stream() failed\n");
 158                 abort();
 159         }
 160
 161         // FFmpeg is very picky about having audio at 1/48000 timebase,
 162         // no matter what we write. Even though we'd prefer our usual 1/120000,
 163         // put the video on the same one, so that we can have locked audio.
 164         stream->time_base = AVRational{ 1, OUTPUT_FREQUENCY };
 165         stream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 166         stream->codecpar->codec_id = AV_CODEC_ID_MJPEG;
 167
 168         // Used for aspect ratio only. Can change without notice (the mux won't care).
 169         stream->codecpar->width = global_flags.width;
 170         stream->codecpar->height = global_flags.height;
 171
 172         // TODO: We could perhaps use the interpretation for each card here
 173         // (or at least the command-line flags) instead of the defaults,
 174         // but what would we do when they change?
 175         stream->codecpar->color_primaries = AVCOL_PRI_BT709;
 176         stream->codecpar->color_trc = AVCOL_TRC_IEC61966_2_1;
 177         stream->codecpar->color_space = AVCOL_SPC_BT709;
 178         stream->codecpar->color_range = AVCOL_RANGE_MPEG;
 179         stream->codecpar->chroma_location = AVCHROMA_LOC_LEFT;
 180         stream->codecpar->field_order = AV_FIELD_PROGRESSIVE;
 181 }
 182
 183 void add_audio_stream(AVFormatContext *avctx)
 184 {
 185         AVStream *stream = avformat_new_stream(avctx, nullptr);
 186         if (stream == nullptr) {
 187                 fprintf(stderr, "avformat_new_stream() failed\n");
 188                 abort();
 189         }
 190         stream->time_base = AVRational{ 1, OUTPUT_FREQUENCY };
 191         stream->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
 192         stream->codecpar->codec_id = AV_CODEC_ID_PCM_S32LE;
 193         stream->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
 194         stream->codecpar->channels = 2;
 195         stream->codecpar->sample_rate = OUTPUT_FREQUENCY;
 196 }
 197
 198 void finalize_mux(AVFormatContext *avctx)
 199 {
 200         AVDictionary *options = NULL;
 201         vector<pair<string, string>> opts = MUX_OPTS;
 202         for (pair<string, string> opt : opts) {
 203                 av_dict_set(&options, opt.first.c_str(), opt.second.c_str(), 0);
 204         }
 205         if (avformat_write_header(avctx, &options) < 0) {
 206                 fprintf(stderr, "avformat_write_header() failed\n");
 207                 abort();
 208         }
 209 }
 210
 211 }  // namespace
 212
 213 MJPEGEncoder::MJPEGEncoder(HTTPD *httpd, const string &va_display)
 214         : httpd(httpd)
 215 {
 216         create_ffmpeg_context(HTTPD::StreamID{ HTTPD::MULTICAM_STREAM, 0 });
 217         for (unsigned stream_idx = 0; stream_idx < MAX_VIDEO_CARDS; ++stream_idx) {
 218                 create_ffmpeg_context(HTTPD::StreamID{ HTTPD::SIPHON_STREAM, stream_idx });
 219         }
 220
 221         add_stream(HTTPD::StreamID{ HTTPD::MULTICAM_STREAM, 0 });
 222
 223         // Initialize VA-API.
 224         VAConfigID config_id_422, config_id_420;
 225         string error;
 226         va_dpy = try_open_va(va_display, { VAProfileJPEGBaseline }, VAEntrypointEncPicture,
 227                 {
 228                         { "4:2:2", VA_RT_FORMAT_YUV422, VA_FOURCC_UYVY, &config_id_422, &uyvy_format },
 229                         // We'd prefer VA_FOURCC_I420, but it's not supported by Intel's driver.
 230                         { "4:2:0", VA_RT_FORMAT_YUV420, VA_FOURCC_NV12, &config_id_420, &nv12_format }
 231                 },
 232                 /*chosen_profile=*/nullptr, &error);
 233         if (va_dpy == nullptr) {
 234                 fprintf(stderr, "Could not initialize VA-API for MJPEG encoding: %s. JPEGs will be encoded in software if needed.\n", error.c_str());
 235         }
 236
 237         encoder_thread = thread(&MJPEGEncoder::encoder_thread_func, this);
 238         if (va_dpy != nullptr) {
 239                 va_pool.reset(new VAResourcePool(va_dpy->va_dpy, uyvy_format, nv12_format, config_id_422, config_id_420, /*with_data_buffer=*/true));
 240                 va_receiver_thread = thread(&MJPEGEncoder::va_receiver_thread_func, this);
 241         }
 242
 243         global_metrics.add("mjpeg_frames", {{ "status", "dropped" }, { "reason", "zero_size" }}, &metric_mjpeg_frames_zero_size_dropped);
 244         global_metrics.add("mjpeg_frames", {{ "status", "dropped" }, { "reason", "interlaced" }}, &metric_mjpeg_frames_interlaced_dropped);
 245         global_metrics.add("mjpeg_frames", {{ "status", "dropped" }, { "reason", "unsupported_pixel_format" }}, &metric_mjpeg_frames_unsupported_pixel_format_dropped);
 246         global_metrics.add("mjpeg_frames", {{ "status", "dropped" }, { "reason", "oversized" }}, &metric_mjpeg_frames_oversized_dropped);
 247         global_metrics.add("mjpeg_frames", {{ "status", "dropped" }, { "reason", "overrun" }}, &metric_mjpeg_overrun_dropped);
 248         global_metrics.add("mjpeg_frames", {{ "status", "submitted" }}, &metric_mjpeg_overrun_submitted);
 249
 250         running = true;
 251 }
 252
 253 MJPEGEncoder::~MJPEGEncoder()
 254 {
 255         for (auto &id_and_stream : streams) {
 256                 av_free(id_and_stream.second.avctx->pb->buffer);
 257         }
 258
 259         global_metrics.remove("mjpeg_frames", {{ "status", "dropped" }, { "reason", "zero_size" }});
 260         global_metrics.remove("mjpeg_frames", {{ "status", "dropped" }, { "reason", "interlaced" }});
 261         global_metrics.remove("mjpeg_frames", {{ "status", "dropped" }, { "reason", "unsupported_pixel_format" }});
 262         global_metrics.remove("mjpeg_frames", {{ "status", "dropped" }, { "reason", "oversized" }});
 263         global_metrics.remove("mjpeg_frames", {{ "status", "dropped" }, { "reason", "overrun" }});
 264         global_metrics.remove("mjpeg_frames", {{ "status", "submitted" }});
 265 }
 266
 267 void MJPEGEncoder::stop()
 268 {
 269         if (!running) {
 270                 return;
 271         }
 272         running = false;
 273         should_quit = true;
 274         any_frames_to_be_encoded.notify_all();
 275         any_frames_encoding.notify_all();
 276         encoder_thread.join();
 277         if (va_dpy != nullptr) {
 278                 va_receiver_thread.join();
 279         }
 280 }
 281
 282 namespace {
 283
 284 bool is_uyvy(RefCountedFrame frame)
 285 {
 286         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)frame->userdata;
 287         return userdata->pixel_format == PixelFormat_8BitYCbCr && frame->interleaved;
 288 }
 289
 290 bool is_i420(RefCountedFrame frame)
 291 {
 292         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)frame->userdata;
 293         return userdata->pixel_format == PixelFormat_8BitYCbCrPlanar &&
 294                 userdata->ycbcr_format.chroma_subsampling_x == 2 &&
 295                 userdata->ycbcr_format.chroma_subsampling_y == 2;
 296 }
 297
 298 }  // namespace
 299
 300 void MJPEGEncoder::upload_frame(int64_t pts, unsigned card_index, RefCountedFrame frame, const bmusb::VideoFormat &video_format, size_t y_offset, size_t cbcr_offset, vector<int32_t> audio, const RGBTriplet &white_balance)
 301 {
 302         if (video_format.width == 0 || video_format.height == 0) {
 303                 ++metric_mjpeg_frames_zero_size_dropped;
 304                 return;
 305         }
 306         if (video_format.interlaced) {
 307                 fprintf(stderr, "Card %u: Ignoring JPEG encoding for interlaced frame\n", card_index);
 308                 ++metric_mjpeg_frames_interlaced_dropped;
 309                 return;
 310         }
 311         if (!is_uyvy(frame) && !is_i420(frame)) {
 312                 fprintf(stderr, "Card %u: Ignoring JPEG encoding for unsupported pixel format\n", card_index);
 313                 ++metric_mjpeg_frames_unsupported_pixel_format_dropped;
 314                 return;
 315         }
 316         if (video_format.width > 4096 || video_format.height > 4096) {
 317                 fprintf(stderr, "Card %u: Ignoring JPEG encoding for oversized frame\n", card_index);
 318                 ++metric_mjpeg_frames_oversized_dropped;
 319                 return;
 320         }
 321
 322         lock_guard<mutex> lock(mu);
 323         if (frames_to_be_encoded.size() + frames_encoding.size() > 50) {
 324                 fprintf(stderr, "WARNING: MJPEG encoding doesn't keep up, discarding frame.\n");
 325                 ++metric_mjpeg_overrun_dropped;
 326                 return;
 327         }
 328         ++metric_mjpeg_overrun_submitted;
 329         frames_to_be_encoded.push(QueuedFrame{ pts, card_index, frame, video_format, y_offset, cbcr_offset, move(audio), white_balance });
 330         any_frames_to_be_encoded.notify_all();
 331 }
 332
 333 bool MJPEGEncoder::should_encode_mjpeg_for_card(unsigned card_index)
 334 {
 335         // Only bother doing MJPEG encoding if there are any connected clients
 336         // that want the stream.
 337         if (httpd->get_num_connected_multicam_clients() == 0 &&
 338             httpd->get_num_connected_siphon_clients(card_index) == 0) {
 339                 return false;
 340         }
 341
 342         auto it = global_flags.card_to_mjpeg_stream_export.find(card_index);
 343         return (it != global_flags.card_to_mjpeg_stream_export.end());
 344 }
 345
 346 void MJPEGEncoder::encoder_thread_func()
 347 {
 348         pthread_setname_np(pthread_self(), "MJPEG_Encode");
 349         posix_memalign((void **)&tmp_y, 4096, 4096 * 8);
 350         posix_memalign((void **)&tmp_cbcr, 4096, 4096 * 8);
 351         posix_memalign((void **)&tmp_cb, 4096, 4096 * 8);
 352         posix_memalign((void **)&tmp_cr, 4096, 4096 * 8);
 353
 354         for (;;) {
 355                 QueuedFrame qf;
 356                 {
 357                         unique_lock<mutex> lock(mu);
 358                         any_frames_to_be_encoded.wait(lock, [this] { return !frames_to_be_encoded.empty() || should_quit; });
 359                         if (should_quit) break;
 360                         qf = move(frames_to_be_encoded.front());
 361                         frames_to_be_encoded.pop();
 362                 }
 363
 364                 assert(global_flags.card_to_mjpeg_stream_export.count(qf.card_index));  // Or should_encode_mjpeg_for_card() would have returned false.
 365                 int stream_index = global_flags.card_to_mjpeg_stream_export[qf.card_index];
 366
 367                 if (va_dpy != nullptr) {
 368                         // Will call back in the receiver thread.
 369                         encode_jpeg_va(move(qf));
 370                 } else {
 371                         update_siphon_streams();
 372
 373                         HTTPD::StreamID multicam_id{ HTTPD::MULTICAM_STREAM, 0 };
 374                         HTTPD::StreamID siphon_id{ HTTPD::SIPHON_STREAM, qf.card_index };
 375                         assert(streams.count(multicam_id));
 376
 377                         // Write audio before video, since Futatabi expects it.
 378                         if (qf.audio.size() > 0) {
 379                                 write_audio_packet(streams[multicam_id].avctx.get(), qf.pts, stream_index + global_flags.card_to_mjpeg_stream_export.size(), qf.audio);
 380                                 if (streams.count(siphon_id)) {
 381                                         write_audio_packet(streams[siphon_id].avctx.get(), qf.pts, /*stream_index=*/1, qf.audio);
 382                                 }
 383                         }
 384
 385                         // Encode synchronously, in the same thread.
 386                         vector<uint8_t> jpeg = encode_jpeg_libjpeg(qf);
 387                         write_mjpeg_packet(streams[multicam_id].avctx.get(), qf.pts, stream_index, jpeg.data(), jpeg.size());
 388                         if (streams.count(siphon_id)) {
 389                                 write_mjpeg_packet(streams[siphon_id].avctx.get(), qf.pts, /*stream_index=*/0, jpeg.data(), jpeg.size());
 390                         }
 391                 }
 392         }
 393
 394         free(tmp_y);
 395         free(tmp_cbcr);
 396         free(tmp_cb);
 397         free(tmp_cr);
 398 }
 399
 400 void MJPEGEncoder::write_mjpeg_packet(AVFormatContext *avctx, int64_t pts, unsigned stream_index, const uint8_t *jpeg, size_t jpeg_size)
 401 {
 402         AVPacket pkt;
 403         memset(&pkt, 0, sizeof(pkt));
 404         pkt.buf = nullptr;
 405         pkt.data = const_cast<uint8_t *>(jpeg);
 406         pkt.size = jpeg_size;
 407         pkt.stream_index = stream_index;
 408         pkt.flags = AV_PKT_FLAG_KEY;
 409         AVRational time_base = avctx->streams[pkt.stream_index]->time_base;
 410         pkt.pts = pkt.dts = av_rescale_q(pts, AVRational{ 1, TIMEBASE }, time_base);
 411         pkt.duration = 0;
 412
 413         if (av_write_frame(avctx, &pkt) < 0) {
 414                 fprintf(stderr, "av_write_frame() failed\n");
 415                 abort();
 416         }
 417 }
 418
 419 void MJPEGEncoder::write_audio_packet(AVFormatContext *avctx, int64_t pts, unsigned stream_index, const vector<int32_t> &audio)
 420 {
 421         AVPacket pkt;
 422         memset(&pkt, 0, sizeof(pkt));
 423         pkt.buf = nullptr;
 424         pkt.data = reinterpret_cast<uint8_t *>(const_cast<int32_t *>(&audio[0]));
 425         pkt.size = audio.size() * sizeof(audio[0]);
 426         pkt.stream_index = stream_index;
 427         pkt.flags = AV_PKT_FLAG_KEY;
 428         AVRational time_base = avctx->streams[pkt.stream_index]->time_base;
 429         pkt.pts = pkt.dts = av_rescale_q(pts, AVRational{ 1, TIMEBASE }, time_base);
 430         size_t num_stereo_samples = audio.size() / 2;
 431         pkt.duration = av_rescale_q(num_stereo_samples, AVRational{ 1, OUTPUT_FREQUENCY }, time_base);
 432
 433         if (av_write_frame(avctx, &pkt) < 0) {
 434                 fprintf(stderr, "av_write_frame() failed\n");
 435                 abort();
 436         }
 437 }
 438
 439 class VABufferDestroyer {
 440 public:
 441         VABufferDestroyer(VADisplay dpy, VABufferID buf)
 442                 : dpy(dpy), buf(buf) {}
 443
 444         ~VABufferDestroyer() {
 445                 VAStatus va_status = vaDestroyBuffer(dpy, buf);
 446                 CHECK_VASTATUS(va_status, "vaDestroyBuffer");
 447         }
 448
 449 private:
 450         VADisplay dpy;
 451         VABufferID buf;
 452 };
 453
 454 namespace {
 455
 456 void push16(uint16_t val, string *str)
 457 {
 458         str->push_back(val >> 8);
 459         str->push_back(val & 0xff);
 460 }
 461
 462 void push32(uint32_t val, string *str)
 463 {
 464         str->push_back(val >> 24);
 465         str->push_back((val >> 16) & 0xff);
 466         str->push_back((val >> 8) & 0xff);
 467         str->push_back(val & 0xff);
 468 }
 469
 470 }  // namespace
 471
 472 void MJPEGEncoder::init_jpeg(unsigned width, unsigned height, const RGBTriplet &white_balance, VectorDestinationManager *dest, jpeg_compress_struct *cinfo, int y_h_samp_factor, int y_v_samp_factor)
 473 {
 474         jpeg_error_mgr jerr;
 475         cinfo->err = jpeg_std_error(&jerr);
 476         jpeg_create_compress(cinfo);
 477
 478         cinfo->dest = (jpeg_destination_mgr *)dest;
 479
 480         cinfo->input_components = 3;
 481         jpeg_set_defaults(cinfo);
 482         jpeg_set_quality(cinfo, quality, /*force_baseline=*/false);
 483
 484         cinfo->image_width = width;
 485         cinfo->image_height = height;
 486         cinfo->raw_data_in = true;
 487         jpeg_set_colorspace(cinfo, JCS_YCbCr);
 488         cinfo->comp_info[0].h_samp_factor = y_h_samp_factor;
 489         cinfo->comp_info[0].v_samp_factor = y_v_samp_factor;
 490         cinfo->comp_info[1].h_samp_factor = 1;
 491         cinfo->comp_info[1].v_samp_factor = 1;
 492         cinfo->comp_info[2].h_samp_factor = 1;
 493         cinfo->comp_info[2].v_samp_factor = 1;
 494         cinfo->CCIR601_sampling = true;  // Seems to be mostly ignored by libjpeg, though.
 495         jpeg_start_compress(cinfo, true);
 496
 497         if (fabs(white_balance.r - 1.0f) > 1e-3 ||
 498             fabs(white_balance.g - 1.0f) > 1e-3 ||
 499             fabs(white_balance.b - 1.0f) > 1e-3) {
 500                 // Convert from (linear) RGB to XYZ.
 501                 Matrix3d rgb_to_xyz_matrix = movit::ColorspaceConversionEffect::get_xyz_matrix(COLORSPACE_sRGB);
 502                 Vector3d xyz = rgb_to_xyz_matrix * Vector3d(white_balance.r, white_balance.g, white_balance.b);
 503
 504                 // Convert from XYZ to xyz by normalizing.
 505                 xyz /= (xyz[0] + xyz[1] + xyz[2]);
 506
 507                 // Create a very rudimentary EXIF header to hold our white point.
 508                 string exif;
 509
 510                 // Exif header, followed by some padding.
 511                 exif = "Exif";
 512                 push16(0, &exif);
 513
 514                 // TIFF header first:
 515                 exif += "MM";  // Big endian.
 516
 517                 // Magic number.
 518                 push16(42, &exif);
 519
 520                 // Offset of first IFD (relative to the MM, immediately after the header).
 521                 push32(exif.size() - 6 + 4, &exif);
 522
 523                 // Now the actual IFD.
 524
 525                 // One entry.
 526                 push16(1, &exif);
 527
 528                 // WhitePoint tag ID.
 529                 push16(0x13e, &exif);
 530
 531                 // Rational type.
 532                 push16(5, &exif);
 533
 534                 // Two values (x and y; z is implicit due to normalization).
 535                 push32(2, &exif);
 536
 537                 // Offset (relative to the MM, immediately after the last IFD).
 538                 push32(exif.size() - 6 + 8, &exif);
 539
 540                 // No more IFDs.
 541                 push32(0, &exif);
 542
 543                 // The actual values.
 544                 push32(lrintf(xyz[0] * 10000.0f), &exif);
 545                 push32(10000, &exif);
 546                 push32(lrintf(xyz[1] * 10000.0f), &exif);
 547                 push32(10000, &exif);
 548
 549                 jpeg_write_marker(cinfo, JPEG_APP0 + 1, (const JOCTET *)exif.data(), exif.size());
 550         }
 551
 552         // This comment marker is private to FFmpeg. It signals limited Y'CbCr range
 553         // (and nothing else).
 554         jpeg_write_marker(cinfo, JPEG_COM, (const JOCTET *)"CS=ITU601", strlen("CS=ITU601"));
 555 }
 556
 557 vector<uint8_t> MJPEGEncoder::get_jpeg_header(unsigned width, unsigned height, const RGBTriplet &white_balance, int y_h_samp_factor, int y_v_samp_factor, jpeg_compress_struct *cinfo)
 558 {
 559         VectorDestinationManager dest;
 560         init_jpeg(width, height, white_balance, &dest, cinfo, y_h_samp_factor, y_v_samp_factor);
 561
 562         // Make a dummy black image; there's seemingly no other easy way of
 563         // making libjpeg outputting all of its headers.
 564         assert(y_v_samp_factor <= 2);  // Or we'd need larger JSAMPROW arrays below.
 565         size_t block_height_y = 8 * y_v_samp_factor;
 566         size_t block_height_cbcr = 8;
 567
 568         JSAMPROW yptr[16], cbptr[16], crptr[16];
 569         JSAMPARRAY data[3] = { yptr, cbptr, crptr };
 570         memset(tmp_y, 0, 4096);
 571         memset(tmp_cb, 0, 4096);
 572         memset(tmp_cr, 0, 4096);
 573         for (unsigned yy = 0; yy < block_height_y; ++yy) {
 574                 yptr[yy] = tmp_y;
 575         }
 576         for (unsigned yy = 0; yy < block_height_cbcr; ++yy) {
 577                 cbptr[yy] = tmp_cb;
 578                 crptr[yy] = tmp_cr;
 579         }
 580         for (unsigned y = 0; y < height; y += block_height_y) {
 581                 jpeg_write_raw_data(cinfo, data, block_height_y);
 582         }
 583         jpeg_finish_compress(cinfo);
 584
 585         // We're only interested in the header, not the data after it.
 586         dest.term_destination();
 587         for (size_t i = 0; i < dest.dest.size() - 1; ++i) {
 588                 if (dest.dest[i] == 0xff && dest.dest[i + 1] == 0xda) {  // Start of scan (SOS).
 589                         unsigned len = dest.dest[i + 2] * 256 + dest.dest[i + 3];
 590                         dest.dest.resize(i + len + 2);
 591                         break;
 592                 }
 593         }
 594
 595         return dest.dest;
 596 }
 597
 598 MJPEGEncoder::VAData MJPEGEncoder::get_va_data_for_parameters(unsigned width, unsigned height, unsigned y_h_samp_factor, unsigned y_v_samp_factor, const RGBTriplet &white_balance)
 599 {
 600         VAKey key{width, height, y_h_samp_factor, y_v_samp_factor, white_balance};
 601         if (va_data_for_parameters.count(key)) {
 602                 return va_data_for_parameters[key];
 603         }
 604
 605         // Use libjpeg to generate a header and set sane defaults for e.g.
 606         // quantization tables. Then do the actual encode with VA-API.
 607         jpeg_compress_struct cinfo;
 608         vector<uint8_t> jpeg_header = get_jpeg_header(width, height, white_balance, y_h_samp_factor, y_v_samp_factor, &cinfo);
 609
 610         // Picture parameters.
 611         VAEncPictureParameterBufferJPEG pic_param;
 612         memset(&pic_param, 0, sizeof(pic_param));
 613         pic_param.reconstructed_picture = VA_INVALID_ID;
 614         pic_param.picture_width = cinfo.image_width;
 615         pic_param.picture_height = cinfo.image_height;
 616         for (int component_idx = 0; component_idx < cinfo.num_components; ++component_idx) {
 617                 const jpeg_component_info *comp = &cinfo.comp_info[component_idx];
 618                 pic_param.component_id[component_idx] = comp->component_id;
 619                 pic_param.quantiser_table_selector[component_idx] = comp->quant_tbl_no;
 620         }
 621         pic_param.num_components = cinfo.num_components;
 622         pic_param.num_scan = 1;
 623         pic_param.sample_bit_depth = 8;
 624         pic_param.coded_buf = VA_INVALID_ID;  // To be filled out by caller.
 625         pic_param.pic_flags.bits.huffman = 1;
 626         pic_param.quality = 50;  // Don't scale the given quantization matrices. (See gen8_mfc_jpeg_fqm_state)
 627
 628         // Quantization matrices.
 629         VAQMatrixBufferJPEG q;
 630         memset(&q, 0, sizeof(q));
 631
 632         q.load_lum_quantiser_matrix = true;
 633         q.load_chroma_quantiser_matrix = true;
 634         for (int quant_tbl_idx = 0; quant_tbl_idx < min(4, NUM_QUANT_TBLS); ++quant_tbl_idx) {
 635                 const JQUANT_TBL *qtbl = cinfo.quant_tbl_ptrs[quant_tbl_idx];
 636                 assert((qtbl == nullptr) == (quant_tbl_idx >= 2));
 637                 if (qtbl == nullptr) continue;
 638
 639                 uint8_t *qmatrix = (quant_tbl_idx == 0) ? q.lum_quantiser_matrix : q.chroma_quantiser_matrix;
 640                 for (int i = 0; i < 64; ++i) {
 641                         if (qtbl->quantval[i] > 255) {
 642                                 fprintf(stderr, "Baseline JPEG only!\n");
 643                                 abort();
 644                         }
 645                         qmatrix[i] = qtbl->quantval[jpeg_natural_order[i]];
 646                 }
 647         }
 648
 649         // Huffman tables (arithmetic is not supported).
 650         VAHuffmanTableBufferJPEGBaseline huff;
 651         memset(&huff, 0, sizeof(huff));
 652
 653         for (int huff_tbl_idx = 0; huff_tbl_idx < min(2, NUM_HUFF_TBLS); ++huff_tbl_idx) {
 654                 const JHUFF_TBL *ac_hufftbl = cinfo.ac_huff_tbl_ptrs[huff_tbl_idx];
 655                 const JHUFF_TBL *dc_hufftbl = cinfo.dc_huff_tbl_ptrs[huff_tbl_idx];
 656                 if (ac_hufftbl == nullptr) {
 657                         assert(dc_hufftbl == nullptr);
 658                         huff.load_huffman_table[huff_tbl_idx] = 0;
 659                 } else {
 660                         assert(dc_hufftbl != nullptr);
 661                         huff.load_huffman_table[huff_tbl_idx] = 1;
 662
 663                         for (int i = 0; i < 16; ++i) {
 664                                 huff.huffman_table[huff_tbl_idx].num_dc_codes[i] = dc_hufftbl->bits[i + 1];
 665                         }
 666                         for (int i = 0; i < 12; ++i) {
 667                                 huff.huffman_table[huff_tbl_idx].dc_values[i] = dc_hufftbl->huffval[i];
 668                         }
 669                         for (int i = 0; i < 16; ++i) {
 670                                 huff.huffman_table[huff_tbl_idx].num_ac_codes[i] = ac_hufftbl->bits[i + 1];
 671                         }
 672                         for (int i = 0; i < 162; ++i) {
 673                                 huff.huffman_table[huff_tbl_idx].ac_values[i] = ac_hufftbl->huffval[i];
 674                         }
 675                 }
 676         }
 677
 678         // Slice parameters (metadata about the slice).
 679         VAEncSliceParameterBufferJPEG parms;
 680         memset(&parms, 0, sizeof(parms));
 681         for (int component_idx = 0; component_idx < cinfo.num_components; ++component_idx) {
 682                 const jpeg_component_info *comp = &cinfo.comp_info[component_idx];
 683                 parms.components[component_idx].component_selector = comp->component_id;
 684                 parms.components[component_idx].dc_table_selector = comp->dc_tbl_no;
 685                 parms.components[component_idx].ac_table_selector = comp->ac_tbl_no;
 686                 if (parms.components[component_idx].dc_table_selector > 1 ||
 687                     parms.components[component_idx].ac_table_selector > 1) {
 688                         fprintf(stderr, "Uses too many Huffman tables\n");
 689                         abort();
 690                 }
 691         }
 692         parms.num_components = cinfo.num_components;
 693         parms.restart_interval = cinfo.restart_interval;
 694
 695         jpeg_destroy_compress(&cinfo);
 696
 697         VAData ret;
 698         ret.jpeg_header = move(jpeg_header);
 699         ret.pic_param = pic_param;
 700         ret.q = q;
 701         ret.huff = huff;
 702         ret.parms = parms;
 703         va_data_for_parameters[key] = ret;
 704         return ret;
 705 }
 706
 707 void MJPEGEncoder::encode_jpeg_va(QueuedFrame &&qf)
 708 {
 709         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)qf.frame->userdata;
 710         unsigned width = qf.video_format.width;
 711         unsigned height = qf.video_format.height;
 712
 713         VAResourcePool::VAResources resources;
 714         ReleaseVAResources release;
 715         if (userdata->data_copy_current_src == PBOFrameAllocator::Userdata::FROM_VA_API) {
 716                 assert(is_uyvy(qf.frame));
 717                 resources = move(userdata->va_resources);
 718                 release = move(userdata->va_resources_release);
 719         } else {
 720                 assert(userdata->data_copy_current_src == PBOFrameAllocator::Userdata::FROM_MALLOC);
 721                 if (is_uyvy(qf.frame)) {
 722                         resources = va_pool->get_va_resources(width, height, VA_FOURCC_UYVY);
 723                 } else {
 724                         assert(is_i420(qf.frame));
 725                         resources = va_pool->get_va_resources(width, height, VA_FOURCC_NV12);
 726                 }
 727                 release = ReleaseVAResources(va_pool.get(), resources);
 728         }
 729
 730         int y_h_samp_factor, y_v_samp_factor;
 731         if (is_uyvy(qf.frame)) {
 732                 // 4:2:2 (sample Y' twice as often horizontally as Cb or Cr, vertical is left alone).
 733                 y_h_samp_factor = 2;
 734                 y_v_samp_factor = 1;
 735         } else {
 736                 // 4:2:0 (sample Y' twice as often as Cb or Cr, in both directions)
 737                 assert(is_i420(qf.frame));
 738                 y_h_samp_factor = 2;
 739                 y_v_samp_factor = 2;
 740         }
 741
 742         VAData va_data = get_va_data_for_parameters(width, height, y_h_samp_factor, y_v_samp_factor, qf.white_balance);
 743         va_data.pic_param.coded_buf = resources.data_buffer;
 744
 745         VABufferID pic_param_buffer;
 746         VAStatus va_status = vaCreateBuffer(va_dpy->va_dpy, resources.context, VAEncPictureParameterBufferType, sizeof(va_data.pic_param), 1, &va_data.pic_param, &pic_param_buffer);
 747         CHECK_VASTATUS(va_status, "vaCreateBuffer");
 748         VABufferDestroyer destroy_pic_param(va_dpy->va_dpy, pic_param_buffer);
 749
 750         VABufferID q_buffer;
 751         va_status = vaCreateBuffer(va_dpy->va_dpy, resources.context, VAQMatrixBufferType, sizeof(va_data.q), 1, &va_data.q, &q_buffer);
 752         CHECK_VASTATUS(va_status, "vaCreateBuffer");
 753         VABufferDestroyer destroy_iq(va_dpy->va_dpy, q_buffer);
 754
 755         VABufferID huff_buffer;
 756         va_status = vaCreateBuffer(va_dpy->va_dpy, resources.context, VAHuffmanTableBufferType, sizeof(va_data.huff), 1, &va_data.huff, &huff_buffer);
 757         CHECK_VASTATUS(va_status, "vaCreateBuffer");
 758         VABufferDestroyer destroy_huff(va_dpy->va_dpy, huff_buffer);
 759
 760         VABufferID slice_param_buffer;
 761         va_status = vaCreateBuffer(va_dpy->va_dpy, resources.context, VAEncSliceParameterBufferType, sizeof(va_data.parms), 1, &va_data.parms, &slice_param_buffer);
 762         CHECK_VASTATUS(va_status, "vaCreateBuffer");
 763         VABufferDestroyer destroy_slice_param(va_dpy->va_dpy, slice_param_buffer);
 764
 765         if (userdata->data_copy_current_src == PBOFrameAllocator::Userdata::FROM_VA_API) {
 766                 // The pixel data is already put into the image by the caller.
 767                 va_status = vaUnmapBuffer(va_dpy->va_dpy, resources.image.buf);
 768                 CHECK_VASTATUS(va_status, "vaUnmapBuffer");
 769         } else {
 770                 assert(userdata->data_copy_current_src == PBOFrameAllocator::Userdata::FROM_MALLOC);
 771
 772                 // Upload the pixel data.
 773                 uint8_t *surface_p = nullptr;
 774                 vaMapBuffer(va_dpy->va_dpy, resources.image.buf, (void **)&surface_p);
 775
 776                 if (is_uyvy(qf.frame)) {
 777                         size_t field_start_line = qf.video_format.extra_lines_top;  // No interlacing support.
 778                         size_t field_start = qf.cbcr_offset * 2 + qf.video_format.width * field_start_line * 2;
 779
 780                         const uint8_t *src = qf.frame->data_copy + field_start;
 781                         uint8_t *dst = (unsigned char *)surface_p + resources.image.offsets[0];
 782                         memcpy_with_pitch(dst, src, qf.video_format.width * 2, resources.image.pitches[0], qf.video_format.height);
 783                 } else {
 784                         assert(is_i420(qf.frame));
 785                         assert(!qf.frame->interleaved);  // Makes no sense for I420.
 786
 787                         size_t field_start_line = qf.video_format.extra_lines_top;  // No interlacing support.
 788                         const uint8_t *y_src = qf.frame->data + qf.video_format.width * field_start_line;
 789                         const uint8_t *cb_src = y_src + width * height;
 790                         const uint8_t *cr_src = cb_src + (width / 2) * (height / 2);
 791
 792                         uint8_t *y_dst = (unsigned char *)surface_p + resources.image.offsets[0];
 793                         uint8_t *cbcr_dst = (unsigned char *)surface_p + resources.image.offsets[1];
 794
 795                         memcpy_with_pitch(y_dst, y_src, qf.video_format.width, resources.image.pitches[0], qf.video_format.height);
 796                         interleave_with_pitch(cbcr_dst, cb_src, cr_src, qf.video_format.width / 2, resources.image.pitches[1], qf.video_format.height / 2);
 797                 }
 798
 799                 va_status = vaUnmapBuffer(va_dpy->va_dpy, resources.image.buf);
 800                 CHECK_VASTATUS(va_status, "vaUnmapBuffer");
 801         }
 802
 803         qf.frame->data_copy = nullptr;
 804
 805         // Seemingly vaPutImage() (which triggers a GPU copy) is much nicer to the
 806         // CPU than vaDeriveImage() and copying directly into the GPU's buffers.
 807         // Exactly why is unclear, but it seems to involve L3 cache usage when there
 808         // are many high-res (1080p+) images in play.
 809         va_status = vaPutImage(va_dpy->va_dpy, resources.surface, resources.image.image_id, 0, 0, width, height, 0, 0, width, height);
 810         CHECK_VASTATUS(va_status, "vaPutImage");
 811
 812         // Finally, stick in the JPEG header.
 813         VAEncPackedHeaderParameterBuffer header_parm;
 814         header_parm.type = VAEncPackedHeaderRawData;
 815         header_parm.bit_length = 8 * va_data.jpeg_header.size();
 816
 817         VABufferID header_parm_buffer;
 818         va_status = vaCreateBuffer(va_dpy->va_dpy, resources.context, VAEncPackedHeaderParameterBufferType, sizeof(header_parm), 1, &header_parm, &header_parm_buffer);
 819         CHECK_VASTATUS(va_status, "vaCreateBuffer");
 820         VABufferDestroyer destroy_header(va_dpy->va_dpy, header_parm_buffer);
 821
 822         VABufferID header_data_buffer;
 823         va_status = vaCreateBuffer(va_dpy->va_dpy, resources.context, VAEncPackedHeaderDataBufferType, va_data.jpeg_header.size(), 1, va_data.jpeg_header.data(), &header_data_buffer);
 824         CHECK_VASTATUS(va_status, "vaCreateBuffer");
 825         VABufferDestroyer destroy_header_data(va_dpy->va_dpy, header_data_buffer);
 826
 827         va_status = vaBeginPicture(va_dpy->va_dpy, resources.context, resources.surface);
 828         CHECK_VASTATUS(va_status, "vaBeginPicture");
 829         va_status = vaRenderPicture(va_dpy->va_dpy, resources.context, &pic_param_buffer, 1);
 830         CHECK_VASTATUS(va_status, "vaRenderPicture(pic_param)");
 831         va_status = vaRenderPicture(va_dpy->va_dpy, resources.context, &q_buffer, 1);
 832         CHECK_VASTATUS(va_status, "vaRenderPicture(q)");
 833         va_status = vaRenderPicture(va_dpy->va_dpy, resources.context, &huff_buffer, 1);
 834         CHECK_VASTATUS(va_status, "vaRenderPicture(huff)");
 835         va_status = vaRenderPicture(va_dpy->va_dpy, resources.context, &slice_param_buffer, 1);
 836         CHECK_VASTATUS(va_status, "vaRenderPicture(slice_param)");
 837         va_status = vaRenderPicture(va_dpy->va_dpy, resources.context, &header_parm_buffer, 1);
 838         CHECK_VASTATUS(va_status, "vaRenderPicture(header_parm)");
 839         va_status = vaRenderPicture(va_dpy->va_dpy, resources.context, &header_data_buffer, 1);
 840         CHECK_VASTATUS(va_status, "vaRenderPicture(header_data)");
 841         va_status = vaEndPicture(va_dpy->va_dpy, resources.context);
 842         CHECK_VASTATUS(va_status, "vaEndPicture");
 843
 844         qf.resources = move(resources);
 845         qf.resource_releaser = move(release);
 846
 847         lock_guard<mutex> lock(mu);
 848         frames_encoding.push(move(qf));
 849         any_frames_encoding.notify_all();
 850 }
 851
 852 void MJPEGEncoder::va_receiver_thread_func()
 853 {
 854         pthread_setname_np(pthread_self(), "MJPEG_Receive");
 855         for (;;) {
 856                 QueuedFrame qf;
 857                 {
 858                         unique_lock<mutex> lock(mu);
 859                         any_frames_encoding.wait(lock, [this] { return !frames_encoding.empty() || should_quit; });
 860                         if (should_quit) return;
 861                         qf = move(frames_encoding.front());
 862                         frames_encoding.pop();
 863                 }
 864
 865                 update_siphon_streams();
 866
 867                 assert(global_flags.card_to_mjpeg_stream_export.count(qf.card_index));  // Or should_encode_mjpeg_for_card() would have returned false.
 868                 int stream_index = global_flags.card_to_mjpeg_stream_export[qf.card_index];
 869
 870                 HTTPD::StreamID multicam_id{ HTTPD::MULTICAM_STREAM, 0 };
 871                 HTTPD::StreamID siphon_id{ HTTPD::SIPHON_STREAM, qf.card_index };
 872                 assert(streams.count(multicam_id));
 873                 assert(streams[multicam_id].avctx != nullptr);
 874
 875                 // Write audio before video, since Futatabi expects it.
 876                 if (qf.audio.size() > 0) {
 877                         write_audio_packet(streams[multicam_id].avctx.get(), qf.pts, stream_index + global_flags.card_to_mjpeg_stream_export.size(), qf.audio);
 878                         if (streams.count(siphon_id)) {
 879                                 write_audio_packet(streams[siphon_id].avctx.get(), qf.pts, /*stream_index=*/1, qf.audio);
 880                         }
 881                 }
 882
 883                 VAStatus va_status = vaSyncSurface(va_dpy->va_dpy, qf.resources.surface);
 884                 CHECK_VASTATUS(va_status, "vaSyncSurface");
 885
 886                 VACodedBufferSegment *segment;
 887                 va_status = vaMapBuffer(va_dpy->va_dpy, qf.resources.data_buffer, (void **)&segment);
 888                 CHECK_VASTATUS(va_status, "vaMapBuffer");
 889
 890                 const uint8_t *coded_buf = reinterpret_cast<uint8_t *>(segment->buf);
 891                 write_mjpeg_packet(streams[multicam_id].avctx.get(), qf.pts, stream_index, coded_buf, segment->size);
 892                 if (streams.count(siphon_id)) {
 893                         write_mjpeg_packet(streams[siphon_id].avctx.get(), qf.pts, /*stream_index=*/0, coded_buf, segment->size);
 894                 }
 895
 896                 va_status = vaUnmapBuffer(va_dpy->va_dpy, qf.resources.data_buffer);
 897                 CHECK_VASTATUS(va_status, "vaUnmapBuffer");
 898         }
 899 }
 900
 901 vector<uint8_t> MJPEGEncoder::encode_jpeg_libjpeg(const QueuedFrame &qf)
 902 {
 903         unsigned width = qf.video_format.width;
 904         unsigned height = qf.video_format.height;
 905
 906         VectorDestinationManager dest;
 907         jpeg_compress_struct cinfo;
 908
 909         size_t field_start_line = qf.video_format.extra_lines_top;  // No interlacing support.
 910
 911         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)qf.frame->userdata;
 912         if (userdata->pixel_format == PixelFormat_8BitYCbCr) {
 913                 init_jpeg(width, height, qf.white_balance, &dest, &cinfo, /*y_h_samp_factor=*/2, /*y_v_samp_factor=*/1);
 914
 915                 assert(qf.frame->interleaved);
 916                 size_t field_start = qf.cbcr_offset * 2 + qf.video_format.width * field_start_line * 2;
 917
 918                 JSAMPROW yptr[8], cbptr[8], crptr[8];
 919                 JSAMPARRAY data[3] = { yptr, cbptr, crptr };
 920                 for (unsigned y = 0; y < qf.video_format.height; y += 8) {
 921                         const uint8_t *src;
 922                         src = qf.frame->data_copy + field_start + y * qf.video_format.width * 2;
 923
 924                         memcpy_interleaved(tmp_cbcr, tmp_y, src, qf.video_format.width * 8 * 2);
 925                         memcpy_interleaved(tmp_cb, tmp_cr, tmp_cbcr, qf.video_format.width * 8);
 926                         for (unsigned yy = 0; yy < 8; ++yy) {
 927                                 yptr[yy] = tmp_y + yy * width;
 928                                 cbptr[yy] = tmp_cb + yy * width / 2;
 929                                 crptr[yy] = tmp_cr + yy * width / 2;
 930                         }
 931                         jpeg_write_raw_data(&cinfo, data, /*num_lines=*/8);
 932                 }
 933         } else {
 934                 assert(userdata->pixel_format == PixelFormat_8BitYCbCrPlanar);
 935
 936                 const movit::YCbCrFormat &ycbcr = userdata->ycbcr_format;
 937                 init_jpeg(width, height, qf.white_balance, &dest, &cinfo, ycbcr.chroma_subsampling_x, ycbcr.chroma_subsampling_y);
 938                 assert(ycbcr.chroma_subsampling_y <= 2);  // Or we'd need larger JSAMPROW arrays below.
 939
 940                 size_t field_start_line = qf.video_format.extra_lines_top;  // No interlacing support.
 941                 const uint8_t *y_start = qf.frame->data + qf.video_format.width * field_start_line;
 942                 const uint8_t *cb_start = y_start + width * height;
 943                 const uint8_t *cr_start = cb_start + (width / ycbcr.chroma_subsampling_x) * (height / ycbcr.chroma_subsampling_y);
 944
 945                 size_t block_height_y = 8 * ycbcr.chroma_subsampling_y;
 946                 size_t block_height_cbcr = 8;
 947
 948                 JSAMPROW yptr[16], cbptr[16], crptr[16];
 949                 JSAMPARRAY data[3] = { yptr, cbptr, crptr };
 950                 for (unsigned y = 0; y < qf.video_format.height; y += block_height_y) {
 951                         for (unsigned yy = 0; yy < block_height_y; ++yy) {
 952                                 yptr[yy] = const_cast<JSAMPROW>(y_start) + (y + yy) * width;
 953                         }
 954                         unsigned cbcr_y = y / ycbcr.chroma_subsampling_y;
 955                         for (unsigned yy = 0; yy < block_height_cbcr; ++yy) {
 956                                 cbptr[yy] = const_cast<JSAMPROW>(cb_start) + (cbcr_y + yy) * width / ycbcr.chroma_subsampling_x;
 957                                 crptr[yy] = const_cast<JSAMPROW>(cr_start) + (cbcr_y + yy) * width / ycbcr.chroma_subsampling_x;
 958                         }
 959                         jpeg_write_raw_data(&cinfo, data, block_height_y);
 960                 }
 961         }
 962         jpeg_finish_compress(&cinfo);
 963
 964         return dest.dest;
 965 }
 966
 967 void MJPEGEncoder::add_stream(HTTPD::StreamID stream_id)
 968 {
 969         AVFormatContextWithCloser avctx;
 970
 971         // Set up the mux. We don't use the Mux wrapper, because it's geared towards
 972         // a situation with only one video stream (and possibly one audio stream)
 973         // with known width/height, and we don't need the extra functionality it provides.
 974         avctx.reset(avformat_alloc_context());
 975         avctx->oformat = av_guess_format("nut", nullptr, nullptr);
 976
 977         uint8_t *buf = (uint8_t *)av_malloc(MUX_BUFFER_SIZE);
 978         avctx->pb = avio_alloc_context(buf, MUX_BUFFER_SIZE, 1, &ffmpeg_contexts[stream_id], nullptr, nullptr, nullptr);
 979         avctx->pb->write_data_type = &MJPEGEncoder::write_packet2_thunk;
 980         avctx->flags = AVFMT_FLAG_CUSTOM_IO;
 981
 982         if (stream_id.type == HTTPD::MULTICAM_STREAM) {
 983                 for (unsigned card_idx = 0; card_idx < global_flags.card_to_mjpeg_stream_export.size(); ++card_idx) {
 984                         add_video_stream(avctx.get());
 985                 }
 986                 for (unsigned card_idx = 0; card_idx < global_flags.card_to_mjpeg_stream_export.size(); ++card_idx) {
 987                         add_audio_stream(avctx.get());
 988                 }
 989         } else {
 990                 assert(stream_id.type == HTTPD::SIPHON_STREAM);
 991                 add_video_stream(avctx.get());
 992                 add_audio_stream(avctx.get());
 993         }
 994         finalize_mux(avctx.get());
 995
 996         Stream s;
 997         s.avctx = move(avctx);
 998         streams[stream_id] = move(s);
 999 }
1000
1001 void MJPEGEncoder::update_siphon_streams()
1002 {
1003         // Bring the list of streams into sync with what the clients need.
1004         for (auto it = streams.begin(); it != streams.end(); ) {
1005                 if (it->first.type != HTTPD::SIPHON_STREAM) {
1006                         ++it;
1007                         continue;
1008                 }
1009                 if (httpd->get_num_connected_siphon_clients(it->first.index) == 0) {
1010                         av_free(it->second.avctx->pb->buffer);
1011                         streams.erase(it++);
1012                 } else {
1013                         ++it;
1014                 }
1015         }
1016         for (unsigned stream_idx = 0; stream_idx < MAX_VIDEO_CARDS; ++stream_idx) {
1017                 HTTPD::StreamID stream_id{ HTTPD::SIPHON_STREAM, stream_idx };
1018                 if (streams.count(stream_id) == 0 && httpd->get_num_connected_siphon_clients(stream_idx) > 0) {
1019                         add_stream(stream_id);
1020                 }
1021         }
1022 }
1023
1024 void MJPEGEncoder::create_ffmpeg_context(HTTPD::StreamID stream_id)
1025 {
1026         ffmpeg_contexts.emplace(stream_id, WritePacket2Context{ this, stream_id });
1027 }