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

   1 #include "video_stream.h"
   2
   3 extern "C" {
   4 #include <libavformat/avformat.h>
   5 #include <libavformat/avio.h>
   6 }
   7
   8 #include <jpeglib.h>
   9 #include <unistd.h>
  10
  11 #include "chroma_subsampler.h"
  12 #include "context.h"
  13 #include "flow.h"
  14 #include "httpd.h"
  15 #include "jpeg_frame_view.h"
  16 #include "movit/util.h"
  17 #include "mux.h"
  18 #include "player.h"
  19 #include "util.h"
  20
  21 #include <epoxy/glx.h>
  22
  23 using namespace std;
  24
  25 extern HTTPD *global_httpd;
  26
  27 namespace {
  28
  29 string read_file(const string &filename)
  30 {
  31         FILE *fp = fopen(filename.c_str(), "rb");
  32         if (fp == nullptr) {
  33                 perror(filename.c_str());
  34                 return "";
  35         }
  36
  37         fseek(fp, 0, SEEK_END);
  38         long len = ftell(fp);
  39         rewind(fp);
  40
  41         string ret;
  42         ret.resize(len);
  43         fread(&ret[0], len, 1, fp);
  44         fclose(fp);
  45         return ret;
  46 }
  47
  48 }  // namespace
  49
  50 struct VectorDestinationManager {
  51         jpeg_destination_mgr pub;
  52         std::vector<uint8_t> dest;
  53
  54         VectorDestinationManager()
  55         {
  56                 pub.init_destination = init_destination_thunk;
  57                 pub.empty_output_buffer = empty_output_buffer_thunk;
  58                 pub.term_destination = term_destination_thunk;
  59         }
  60
  61         static void init_destination_thunk(j_compress_ptr ptr)
  62         {
  63                 ((VectorDestinationManager *)(ptr->dest))->init_destination();
  64         }
  65
  66         inline void init_destination()
  67         {
  68                 make_room(0);
  69         }
  70
  71         static boolean empty_output_buffer_thunk(j_compress_ptr ptr)
  72         {
  73                 return ((VectorDestinationManager *)(ptr->dest))->empty_output_buffer();
  74         }
  75
  76         inline bool empty_output_buffer()
  77         {
  78                 make_room(dest.size());  // Should ignore pub.free_in_buffer!
  79                 return true;
  80         }
  81
  82         inline void make_room(size_t bytes_used)
  83         {
  84                 dest.resize(bytes_used + 4096);
  85                 dest.resize(dest.capacity());
  86                 pub.next_output_byte = dest.data() + bytes_used;
  87                 pub.free_in_buffer = dest.size() - bytes_used;
  88         }
  89
  90         static void term_destination_thunk(j_compress_ptr ptr)
  91         {
  92                 ((VectorDestinationManager *)(ptr->dest))->term_destination();
  93         }
  94
  95         inline void term_destination()
  96         {
  97                 dest.resize(dest.size() - pub.free_in_buffer);
  98         }
  99 };
 100 static_assert(std::is_standard_layout<VectorDestinationManager>::value, "");
 101
 102 vector<uint8_t> encode_jpeg(const uint8_t *y_data, const uint8_t *cb_data, const uint8_t *cr_data, unsigned width, unsigned height)
 103 {
 104         VectorDestinationManager dest;
 105
 106         jpeg_compress_struct cinfo;
 107         jpeg_error_mgr jerr;
 108         cinfo.err = jpeg_std_error(&jerr);
 109         jpeg_create_compress(&cinfo);
 110
 111         cinfo.dest = (jpeg_destination_mgr *)&dest;
 112         cinfo.input_components = 3;
 113         cinfo.in_color_space = JCS_RGB;
 114         jpeg_set_defaults(&cinfo);
 115         constexpr int quality = 90;
 116         jpeg_set_quality(&cinfo, quality, /*force_baseline=*/false);
 117
 118         cinfo.image_width = width;
 119         cinfo.image_height = height;
 120         cinfo.raw_data_in = true;
 121         jpeg_set_colorspace(&cinfo, JCS_YCbCr);
 122         cinfo.comp_info[0].h_samp_factor = 2;
 123         cinfo.comp_info[0].v_samp_factor = 1;
 124         cinfo.comp_info[1].h_samp_factor = 1;
 125         cinfo.comp_info[1].v_samp_factor = 1;
 126         cinfo.comp_info[2].h_samp_factor = 1;
 127         cinfo.comp_info[2].v_samp_factor = 1;
 128         cinfo.CCIR601_sampling = true;  // Seems to be mostly ignored by libjpeg, though.
 129         jpeg_start_compress(&cinfo, true);
 130
 131         JSAMPROW yptr[8], cbptr[8], crptr[8];
 132         JSAMPARRAY data[3] = { yptr, cbptr, crptr };
 133         for (unsigned y = 0; y < height; y += 8) {
 134                 for (unsigned yy = 0; yy < 8; ++yy) {
 135                         yptr[yy] = const_cast<JSAMPROW>(&y_data[(height - y - yy - 1) * width]);
 136                         cbptr[yy] = const_cast<JSAMPROW>(&cb_data[(height - y - yy - 1) * width/2]);
 137                         crptr[yy] = const_cast<JSAMPROW>(&cr_data[(height - y - yy - 1) * width/2]);
 138                 }
 139
 140                 jpeg_write_raw_data(&cinfo, data, /*num_lines=*/8);
 141         }
 142
 143         jpeg_finish_compress(&cinfo);
 144         jpeg_destroy_compress(&cinfo);
 145
 146         return move(dest.dest);
 147 }
 148
 149 VideoStream::VideoStream()
 150 {
 151         using namespace movit;
 152
 153         ImageFormat inout_format;
 154         inout_format.color_space = COLORSPACE_sRGB;
 155         inout_format.gamma_curve = GAMMA_sRGB;
 156
 157         ycbcr_format.luma_coefficients = YCBCR_REC_709;
 158         ycbcr_format.full_range = true;  // JPEG.
 159         ycbcr_format.num_levels = 256;
 160         ycbcr_format.chroma_subsampling_x = 2;
 161         ycbcr_format.chroma_subsampling_y = 1;
 162         ycbcr_format.cb_x_position = 0.0f;  // H.264 -- _not_ JPEG, even though our input is MJPEG-encoded
 163         ycbcr_format.cb_y_position = 0.5f;  // Irrelevant.
 164         ycbcr_format.cr_x_position = 0.0f;
 165         ycbcr_format.cr_y_position = 0.5f;
 166
 167         YCbCrFormat ycbcr_output_format = ycbcr_format;
 168         ycbcr_output_format.chroma_subsampling_x = 1;
 169
 170         // TODO: deduplicate code against JPEGFrameView?
 171         ycbcr_planar_convert_chain.reset(new EffectChain(1280, 720));
 172         ycbcr_planar_input = (movit::YCbCrInput *)ycbcr_planar_convert_chain->add_input(new YCbCrInput(inout_format, ycbcr_format, 1280, 720, YCBCR_INPUT_PLANAR));
 173
 174         // One full Y'CbCr texture (for interpolation), one that's just Y (throwing away the
 175         // Cb and Cr channels). The second copy is sort of redundant, but it's the easiest way
 176         // of getting the gray data into a layered texture.
 177         ycbcr_planar_convert_chain->add_ycbcr_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED, ycbcr_output_format);
 178         ycbcr_planar_convert_chain->add_ycbcr_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED, ycbcr_output_format);
 179         ycbcr_planar_convert_chain->set_dither_bits(8);
 180         ycbcr_planar_convert_chain->finalize();
 181
 182         // Same, for semiplanar inputs.
 183         ycbcr_semiplanar_convert_chain.reset(new EffectChain(1280, 720));
 184         ycbcr_semiplanar_input = (movit::YCbCrInput *)ycbcr_semiplanar_convert_chain->add_input(new YCbCrInput(inout_format, ycbcr_format, 1280, 720, YCBCR_INPUT_SPLIT_Y_AND_CBCR));
 185
 186         // One full Y'CbCr texture (for interpolation), one that's just Y (throwing away the
 187         // Cb and Cr channels). The second copy is sort of redundant, but it's the easiest way
 188         // of getting the gray data into a layered texture.
 189         ycbcr_semiplanar_convert_chain->add_ycbcr_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED, ycbcr_output_format);
 190         ycbcr_semiplanar_convert_chain->add_ycbcr_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED, ycbcr_output_format);
 191         ycbcr_semiplanar_convert_chain->set_dither_bits(8);
 192         ycbcr_semiplanar_convert_chain->finalize();
 193
 194         GLuint input_tex[num_interpolate_slots], gray_tex[num_interpolate_slots], cb_tex[num_interpolate_slots], cr_tex[num_interpolate_slots];
 195         glCreateTextures(GL_TEXTURE_2D_ARRAY, 10, input_tex);
 196         glCreateTextures(GL_TEXTURE_2D_ARRAY, 10, gray_tex);
 197         glCreateTextures(GL_TEXTURE_2D, 10, cb_tex);
 198         glCreateTextures(GL_TEXTURE_2D, 10, cr_tex);
 199         check_error();
 200         constexpr size_t width = 1280, height = 720;  // FIXME: adjustable width, height
 201         int levels = find_num_levels(width, height);
 202         for (size_t i = 0; i < num_interpolate_slots; ++i) {
 203                 glTextureStorage3D(input_tex[i], levels, GL_RGBA8, width, height, 2);
 204                 check_error();
 205                 glTextureStorage3D(gray_tex[i], levels, GL_R8, width, height, 2);
 206                 check_error();
 207                 glTextureStorage2D(cb_tex[i], 1, GL_R8, width / 2, height);
 208                 check_error();
 209                 glTextureStorage2D(cr_tex[i], 1, GL_R8, width / 2, height);
 210                 check_error();
 211
 212                 InterpolatedFrameResources resource;
 213                 resource.input_tex = input_tex[i];
 214                 resource.gray_tex = gray_tex[i];
 215                 resource.cb_tex = cb_tex[i];
 216                 resource.cr_tex = cr_tex[i];
 217                 glCreateFramebuffers(2, resource.input_fbos);
 218                 check_error();
 219
 220                 glNamedFramebufferTextureLayer(resource.input_fbos[0], GL_COLOR_ATTACHMENT0, input_tex[i], 0, 0);
 221                 check_error();
 222                 glNamedFramebufferTextureLayer(resource.input_fbos[0], GL_COLOR_ATTACHMENT1, gray_tex[i], 0, 0);
 223                 check_error();
 224                 glNamedFramebufferTextureLayer(resource.input_fbos[1], GL_COLOR_ATTACHMENT0, input_tex[i], 0, 1);
 225                 check_error();
 226                 glNamedFramebufferTextureLayer(resource.input_fbos[1], GL_COLOR_ATTACHMENT1, gray_tex[i], 0, 1);
 227                 check_error();
 228
 229                 GLuint bufs[] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 };
 230                 glNamedFramebufferDrawBuffers(resource.input_fbos[0], 2, bufs);
 231                 check_error();
 232                 glNamedFramebufferDrawBuffers(resource.input_fbos[1], 2, bufs);
 233                 check_error();
 234
 235                 glCreateBuffers(1, &resource.pbo);
 236                 check_error();
 237                 glNamedBufferStorage(resource.pbo, width * height * 4, nullptr, GL_MAP_READ_BIT | GL_MAP_PERSISTENT_BIT);
 238                 check_error();
 239                 resource.pbo_contents = glMapNamedBufferRange(resource.pbo, 0, width * height * 4, GL_MAP_READ_BIT | GL_MAP_PERSISTENT_BIT);
 240                 interpolate_resources.push_back(resource);
 241         }
 242
 243         check_error();
 244
 245         compute_flow.reset(new DISComputeFlow(width, height, operating_point2));
 246         interpolate.reset(new Interpolate(operating_point2, /*split_ycbcr_output=*/true));
 247         chroma_subsampler.reset(new ChromaSubsampler);
 248         check_error();
 249 }
 250
 251 VideoStream::~VideoStream() {}
 252
 253 void VideoStream::start()
 254 {
 255         AVFormatContext *avctx = avformat_alloc_context();
 256         avctx->oformat = av_guess_format("nut", nullptr, nullptr);
 257
 258         uint8_t *buf = (uint8_t *)av_malloc(MUX_BUFFER_SIZE);
 259         avctx->pb = avio_alloc_context(buf, MUX_BUFFER_SIZE, 1, this, nullptr, nullptr, nullptr);
 260         avctx->pb->write_data_type = &VideoStream::write_packet2_thunk;
 261         avctx->pb->ignore_boundary_point = 1;
 262
 263         Mux::Codec video_codec = Mux::CODEC_MJPEG;
 264
 265         avctx->flags = AVFMT_FLAG_CUSTOM_IO;
 266
 267         string video_extradata;
 268
 269         constexpr int width = 1280, height = 720;  // Doesn't matter for MJPEG.
 270         stream_mux.reset(new Mux(avctx, width, height, video_codec, video_extradata, /*audio_codec_parameters=*/nullptr, COARSE_TIMEBASE,
 271                 /*write_callback=*/nullptr, Mux::WRITE_FOREGROUND, {}));
 272
 273
 274         encode_thread = thread(&VideoStream::encode_thread_func, this);
 275 }
 276
 277 void VideoStream::stop()
 278 {
 279         encode_thread.join();
 280 }
 281
 282 void VideoStream::schedule_original_frame(int64_t output_pts, unsigned stream_idx, int64_t input_pts)
 283 {
 284         fprintf(stderr, "output_pts=%ld  original      input_pts=%ld\n", output_pts, input_pts);
 285
 286         QueuedFrame qf;
 287         qf.type = QueuedFrame::ORIGINAL;
 288         qf.output_pts = output_pts;
 289         qf.stream_idx = stream_idx;
 290         qf.input_first_pts = input_pts;
 291
 292         unique_lock<mutex> lock(queue_lock);
 293         frame_queue.push_back(qf);
 294         queue_nonempty.notify_all();
 295 }
 296
 297 void VideoStream::schedule_interpolated_frame(int64_t output_pts, unsigned stream_idx, int64_t input_first_pts, int64_t input_second_pts, float alpha)
 298 {
 299         fprintf(stderr, "output_pts=%ld  interpolated  input_pts1=%ld input_pts2=%ld alpha=%.3f\n", output_pts, input_first_pts, input_second_pts, alpha);
 300
 301         // Get the temporary OpenGL resources we need for doing the interpolation.
 302         InterpolatedFrameResources resources;
 303         {
 304                 unique_lock<mutex> lock(queue_lock);
 305                 if (interpolate_resources.empty()) {
 306                         fprintf(stderr, "WARNING: Too many interpolated frames already in transit; dropping one.\n");
 307                         JPEGFrameView::insert_interpolated_frame(stream_idx, output_pts, nullptr);
 308                         return;
 309                 }
 310                 resources = interpolate_resources.front();
 311                 interpolate_resources.pop_front();
 312         }
 313
 314         QueuedFrame qf;
 315         qf.type = QueuedFrame::INTERPOLATED;
 316         qf.output_pts = output_pts;
 317         qf.stream_idx = stream_idx;
 318         qf.resources = resources;
 319
 320         check_error();
 321
 322         // Convert frame0 and frame1 to OpenGL textures.
 323         // TODO: Deduplicate against JPEGFrameView::setDecodedFrame?
 324         for (size_t frame_no = 0; frame_no < 2; ++frame_no) {
 325                 JPEGID jpeg_id;
 326                 jpeg_id.stream_idx = stream_idx;
 327                 jpeg_id.pts = frame_no == 1 ? input_second_pts : input_first_pts;
 328                 jpeg_id.interpolated = false;
 329                 bool did_decode;
 330                 shared_ptr<Frame> frame = decode_jpeg_with_cache(jpeg_id, DECODE_IF_NOT_IN_CACHE, &did_decode);
 331                 ycbcr_format.chroma_subsampling_x = frame->chroma_subsampling_x;
 332                 ycbcr_format.chroma_subsampling_y = frame->chroma_subsampling_y;
 333
 334                 if (frame->is_semiplanar) {
 335                         ycbcr_semiplanar_input->change_ycbcr_format(ycbcr_format);
 336                         ycbcr_semiplanar_input->set_width(frame->width);
 337                         ycbcr_semiplanar_input->set_height(frame->height);
 338                         ycbcr_semiplanar_input->set_pixel_data(0, frame->y.get());
 339                         ycbcr_semiplanar_input->set_pixel_data(1, frame->cbcr.get());
 340                         ycbcr_semiplanar_input->set_pitch(0, frame->pitch_y);
 341                         ycbcr_semiplanar_input->set_pitch(1, frame->pitch_chroma);
 342                         ycbcr_semiplanar_convert_chain->render_to_fbo(resources.input_fbos[frame_no], 1280, 720);
 343                 } else {
 344                         ycbcr_planar_input->change_ycbcr_format(ycbcr_format);
 345                         ycbcr_planar_input->set_width(frame->width);
 346                         ycbcr_planar_input->set_height(frame->height);
 347                         ycbcr_planar_input->set_pixel_data(0, frame->y.get());
 348                         ycbcr_planar_input->set_pixel_data(1, frame->cb.get());
 349                         ycbcr_planar_input->set_pixel_data(2, frame->cr.get());
 350                         ycbcr_planar_input->set_pitch(0, frame->pitch_y);
 351                         ycbcr_planar_input->set_pitch(1, frame->pitch_chroma);
 352                         ycbcr_planar_input->set_pitch(2, frame->pitch_chroma);
 353                         ycbcr_planar_convert_chain->render_to_fbo(resources.input_fbos[frame_no], 1280, 720);
 354                 }
 355         }
 356
 357         glGenerateTextureMipmap(resources.input_tex);
 358         check_error();
 359         glGenerateTextureMipmap(resources.gray_tex);
 360         check_error();
 361
 362         // Compute the interpolated frame.
 363         qf.flow_tex = compute_flow->exec(resources.gray_tex, DISComputeFlow::FORWARD_AND_BACKWARD, DISComputeFlow::DO_NOT_RESIZE_FLOW);
 364         check_error();
 365         tie(qf.output_tex, qf.cbcr_tex) = interpolate->exec(resources.input_tex, resources.gray_tex, qf.flow_tex, 1280, 720, alpha);
 366         check_error();
 367
 368         // Subsample and split Cb/Cr.
 369         chroma_subsampler->subsample_chroma(qf.cbcr_tex, 1280, 720, resources.cb_tex, resources.cr_tex);
 370
 371         // We could have released qf.flow_tex here, but to make sure we don't cause a stall
 372         // when trying to reuse it for the next frame, we can just as well hold on to it
 373         // and release it only when the readback is done.
 374
 375         // Read it down (asynchronously) to the CPU.
 376         glPixelStorei(GL_PACK_ROW_LENGTH, 0);
 377         glBindBuffer(GL_PIXEL_PACK_BUFFER, resources.pbo);
 378         check_error();
 379         glGetTextureImage(qf.output_tex, 0, GL_RED, GL_UNSIGNED_BYTE, 1280 * 720 * 4, BUFFER_OFFSET(0));
 380         check_error();
 381         glGetTextureImage(resources.cb_tex, 0, GL_RED, GL_UNSIGNED_BYTE, 1280 * 720 * 3, BUFFER_OFFSET(1280 * 720));
 382         check_error();
 383         glGetTextureImage(resources.cr_tex, 0, GL_RED, GL_UNSIGNED_BYTE, 1280 * 720 * 3 - 640 * 720, BUFFER_OFFSET(1280 * 720 + 640 * 720));
 384         check_error();
 385         glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
 386
 387         // Set a fence we can wait for to make sure the CPU sees the read.
 388         glMemoryBarrier(GL_CLIENT_MAPPED_BUFFER_BARRIER_BIT);
 389         check_error();
 390         qf.fence = RefCountedGLsync(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
 391         check_error();
 392
 393         unique_lock<mutex> lock(queue_lock);
 394         frame_queue.push_back(qf);
 395         queue_nonempty.notify_all();
 396 }
 397
 398 void VideoStream::encode_thread_func()
 399 {
 400         pthread_setname_np(pthread_self(), "VideoStream");
 401         QSurface *surface = create_surface();
 402         QOpenGLContext *context = create_context(surface);
 403         bool ok = make_current(context, surface);
 404         if (!ok) {
 405                 fprintf(stderr, "Video stream couldn't get an OpenGL context\n");
 406                 exit(1);
 407         }
 408
 409         for ( ;; ) {
 410                 QueuedFrame qf;
 411                 {
 412                         unique_lock<mutex> lock(queue_lock);
 413                         queue_nonempty.wait(lock, [this]{
 414                                 return !frame_queue.empty();
 415                         });
 416                         qf = frame_queue.front();
 417                         frame_queue.pop_front();
 418                 }
 419
 420                 if (qf.type == QueuedFrame::ORIGINAL) {
 421                         // Send the JPEG frame on, unchanged.
 422                         string jpeg = read_file(filename_for_frame(qf.stream_idx, qf.input_first_pts));
 423                         AVPacket pkt;
 424                         av_init_packet(&pkt);
 425                         pkt.stream_index = 0;
 426                         pkt.data = (uint8_t *)jpeg.data();
 427                         pkt.size = jpeg.size();
 428                         stream_mux->add_packet(pkt, qf.output_pts, qf.output_pts);
 429                 } else if (qf.type == QueuedFrame::INTERPOLATED) {
 430                         glClientWaitSync(qf.fence.get(), /*flags=*/0, GL_TIMEOUT_IGNORED);
 431
 432                         const uint8_t *y = (const uint8_t *)qf.resources.pbo_contents;
 433                         const uint8_t *cb = (const uint8_t *)qf.resources.pbo_contents + 1280 * 720;
 434                         const uint8_t *cr = (const uint8_t *)qf.resources.pbo_contents + 1280 * 720 + 640 * 720;
 435
 436                         // Send a copy of the frame on to display.
 437                         shared_ptr<Frame> frame(new Frame);
 438                         frame->y.reset(new uint8_t[1280 * 720]);
 439                         frame->cb.reset(new uint8_t[640 * 720]);
 440                         frame->cr.reset(new uint8_t[640 * 720]);
 441                         for (unsigned yy = 0; yy < 720; ++yy) {
 442                                 memcpy(frame->y.get() + 1280 * yy, y + 1280 * (719 - yy), 1280);
 443                                 memcpy(frame->cb.get() + 640 * yy, cb + 640 * (719 - yy), 640);
 444                                 memcpy(frame->cr.get() + 640 * yy, cr + 640 * (719 - yy), 640);
 445                         }
 446                         frame->is_semiplanar = false;
 447                         frame->width = 1280;
 448                         frame->height = 720;
 449                         frame->chroma_subsampling_x = 2;
 450                         frame->chroma_subsampling_y = 1;
 451                         frame->pitch_y = 1280;
 452                         frame->pitch_chroma = 640;
 453                         JPEGFrameView::insert_interpolated_frame(qf.stream_idx, qf.output_pts, std::move(frame));
 454
 455                         // Now JPEG encode it, and send it on to the stream.
 456                         vector<uint8_t> jpeg = encode_jpeg(y, cb, cr, 1280, 720);
 457                         compute_flow->release_texture(qf.flow_tex);
 458                         interpolate->release_texture(qf.output_tex);
 459                         interpolate->release_texture(qf.cbcr_tex);
 460
 461                         AVPacket pkt;
 462                         av_init_packet(&pkt);
 463                         pkt.stream_index = 0;
 464                         pkt.data = (uint8_t *)jpeg.data();
 465                         pkt.size = jpeg.size();
 466                         stream_mux->add_packet(pkt, qf.output_pts, qf.output_pts);
 467
 468                         // Put the frame resources back.
 469                         unique_lock<mutex> lock(queue_lock);
 470                         interpolate_resources.push_back(qf.resources);
 471                 }
 472         }
 473 }
 474
 475 int VideoStream::write_packet2_thunk(void *opaque, uint8_t *buf, int buf_size, AVIODataMarkerType type, int64_t time)
 476 {
 477         VideoStream *video_stream = (VideoStream *)opaque;
 478         return video_stream->write_packet2(buf, buf_size, type, time);
 479 }
 480
 481 int VideoStream::write_packet2(uint8_t *buf, int buf_size, AVIODataMarkerType type, int64_t time)
 482 {
 483         if (type == AVIO_DATA_MARKER_SYNC_POINT || type == AVIO_DATA_MARKER_BOUNDARY_POINT) {
 484                 seen_sync_markers = true;
 485         } else if (type == AVIO_DATA_MARKER_UNKNOWN && !seen_sync_markers) {
 486                 // We don't know if this is a keyframe or not (the muxer could
 487                 // avoid marking it), so we just have to make the best of it.
 488                 type = AVIO_DATA_MARKER_SYNC_POINT;
 489         }
 490
 491         if (type == AVIO_DATA_MARKER_HEADER) {
 492                 stream_mux_header.append((char *)buf, buf_size);
 493                 global_httpd->set_header(stream_mux_header);
 494         } else {
 495                 global_httpd->add_data((char *)buf, buf_size, type == AVIO_DATA_MARKER_SYNC_POINT, time, AVRational{ AV_TIME_BASE, 1 });
 496         }
 497         return buf_size;
 498 }
 499