git.sesse.net Git - nageru/blob - futatabi/jpeg_frame_view.cpp

   1 #include "jpeg_frame_view.h"
   2
   3 #include "defs.h"
   4 #include "flags.h"
   5 #include "jpeg_destroyer.h"
   6 #include "jpeglib_error_wrapper.h"
   7 #include "shared/metrics.h"
   8 #include "shared/post_to_main_thread.h"
   9 #include "video_stream.h"
  10 #include "ycbcr_converter.h"
  11
  12 #include <QMouseEvent>
  13 #include <QScreen>
  14 #include <atomic>
  15 #include <condition_variable>
  16 #include <deque>
  17 #include <jpeglib.h>
  18 #include <movit/init.h>
  19 #include <movit/resource_pool.h>
  20 #include <movit/util.h>
  21 #include <mutex>
  22 #include <stdint.h>
  23 #include <thread>
  24 #include <unistd.h>
  25 #include <utility>
  26
  27 // Must come after the Qt stuff.
  28 #include "vaapi_jpeg_decoder.h"
  29
  30 using namespace movit;
  31 using namespace std;
  32
  33 namespace {
  34
  35 // Just an arbitrary order for std::map.
  36 struct FrameOnDiskLexicalOrder {
  37         bool operator()(const FrameOnDisk &a, const FrameOnDisk &b) const
  38         {
  39                 if (a.pts != b.pts)
  40                         return a.pts < b.pts;
  41                 if (a.offset != b.offset)
  42                         return a.offset < b.offset;
  43                 if (a.filename_idx != b.filename_idx)
  44                         return a.filename_idx < b.filename_idx;
  45                 assert(a.size == b.size);
  46                 return false;
  47         }
  48 };
  49
  50 inline size_t frame_size(const Frame &frame)
  51 {
  52         size_t y_size = frame.width * frame.height;
  53         size_t cbcr_size = y_size / frame.chroma_subsampling_x / frame.chroma_subsampling_y;
  54         return y_size + cbcr_size * 2;
  55 }
  56
  57 struct LRUFrame {
  58         shared_ptr<Frame> frame;
  59         size_t last_used;
  60 };
  61
  62 struct PendingDecode {
  63         JPEGFrameView *destination;
  64
  65         // For actual decodes (only if frame below is nullptr).
  66         FrameOnDisk primary, secondary;
  67         float fade_alpha;  // Irrelevant if secondary.stream_idx == -1.
  68
  69         // Already-decoded frames are also sent through PendingDecode,
  70         // so that they get drawn in the right order. If frame is nullptr,
  71         // it's a real decode.
  72         shared_ptr<Frame> frame;
  73 };
  74
  75 // There can be multiple JPEGFrameView instances, so make all the metrics static.
  76 once_flag jpeg_metrics_inited;
  77 atomic<int64_t> metric_jpeg_cache_used_bytes{ 0 };  // Same value as cache_bytes_used.
  78 atomic<int64_t> metric_jpeg_cache_limit_bytes{ size_t(CACHE_SIZE_MB) * 1024 * 1024 };
  79 atomic<int64_t> metric_jpeg_cache_given_up_frames{ 0 };
  80 atomic<int64_t> metric_jpeg_cache_hit_frames{ 0 };
  81 atomic<int64_t> metric_jpeg_cache_miss_frames{ 0 };
  82 atomic<int64_t> metric_jpeg_software_decode_frames{ 0 };
  83 atomic<int64_t> metric_jpeg_software_fail_frames{ 0 };
  84 atomic<int64_t> metric_jpeg_vaapi_decode_frames{ 0 };
  85 atomic<int64_t> metric_jpeg_vaapi_fail_frames{ 0 };
  86
  87 }  // namespace
  88
  89 thread JPEGFrameView::jpeg_decoder_thread;
  90 mutex cache_mu;
  91 map<FrameOnDisk, LRUFrame, FrameOnDiskLexicalOrder> cache;  // Under cache_mu.
  92 size_t cache_bytes_used = 0;  // Under cache_mu.
  93 condition_variable any_pending_decodes;
  94 deque<PendingDecode> pending_decodes;  // Under cache_mu.
  95 atomic<size_t> event_counter{ 0 };
  96 extern QGLWidget *global_share_widget;
  97 extern atomic<bool> should_quit;
  98
  99 shared_ptr<Frame> decode_jpeg(const string &jpeg)
 100 {
 101         shared_ptr<Frame> frame;
 102         if (vaapi_jpeg_decoding_usable) {
 103                 frame = decode_jpeg_vaapi(jpeg);
 104                 if (frame != nullptr) {
 105                         ++metric_jpeg_vaapi_decode_frames;
 106                         return frame;
 107                 }
 108                 fprintf(stderr, "VA-API hardware decoding failed; falling back to software.\n");
 109                 ++metric_jpeg_vaapi_fail_frames;
 110         }
 111
 112         frame.reset(new Frame);
 113
 114         jpeg_decompress_struct dinfo;
 115         JPEGWrapErrorManager error_mgr(&dinfo);
 116         if (!error_mgr.run([&dinfo] { jpeg_create_decompress(&dinfo); })) {
 117                 return get_black_frame();
 118         }
 119         JPEGDestroyer destroy_dinfo(&dinfo);
 120
 121         if (!error_mgr.run([&dinfo, &jpeg] {
 122                     jpeg_mem_src(&dinfo, reinterpret_cast<const unsigned char *>(jpeg.data()), jpeg.size());
 123                     jpeg_read_header(&dinfo, true);
 124             })) {
 125                 return get_black_frame();
 126         }
 127
 128         if (dinfo.num_components != 3) {
 129                 fprintf(stderr, "Not a color JPEG. (%d components, Y=%dx%d, Cb=%dx%d, Cr=%dx%d)\n",
 130                         dinfo.num_components,
 131                         dinfo.comp_info[0].h_samp_factor, dinfo.comp_info[0].v_samp_factor,
 132                         dinfo.comp_info[1].h_samp_factor, dinfo.comp_info[1].v_samp_factor,
 133                         dinfo.comp_info[2].h_samp_factor, dinfo.comp_info[2].v_samp_factor);
 134                 return get_black_frame();
 135         }
 136         if (dinfo.comp_info[0].h_samp_factor != dinfo.max_h_samp_factor ||
 137             dinfo.comp_info[0].v_samp_factor != dinfo.max_v_samp_factor ||  // Y' must not be subsampled.
 138             dinfo.comp_info[1].h_samp_factor != dinfo.comp_info[2].h_samp_factor ||
 139             dinfo.comp_info[1].v_samp_factor != dinfo.comp_info[2].v_samp_factor ||  // Cb and Cr must be identically subsampled.
 140             (dinfo.max_h_samp_factor % dinfo.comp_info[1].h_samp_factor) != 0 ||
 141             (dinfo.max_v_samp_factor % dinfo.comp_info[1].v_samp_factor) != 0) {  // No 2:3 subsampling or other weirdness.
 142                 fprintf(stderr, "Unsupported subsampling scheme. (Y=%dx%d, Cb=%dx%d, Cr=%dx%d)\n",
 143                         dinfo.comp_info[0].h_samp_factor, dinfo.comp_info[0].v_samp_factor,
 144                         dinfo.comp_info[1].h_samp_factor, dinfo.comp_info[1].v_samp_factor,
 145                         dinfo.comp_info[2].h_samp_factor, dinfo.comp_info[2].v_samp_factor);
 146                 exit(1);
 147         }
 148         dinfo.raw_data_out = true;
 149
 150         if (!error_mgr.run([&dinfo] {
 151                     jpeg_start_decompress(&dinfo);
 152             })) {
 153                 return get_black_frame();
 154         }
 155
 156         frame->width = dinfo.output_width;
 157         frame->height = dinfo.output_height;
 158         frame->chroma_subsampling_x = dinfo.max_h_samp_factor / dinfo.comp_info[1].h_samp_factor;
 159         frame->chroma_subsampling_y = dinfo.max_v_samp_factor / dinfo.comp_info[1].v_samp_factor;
 160
 161         unsigned h_mcu_size = DCTSIZE * dinfo.max_h_samp_factor;
 162         unsigned v_mcu_size = DCTSIZE * dinfo.max_v_samp_factor;
 163         unsigned mcu_width_blocks = (dinfo.output_width + h_mcu_size - 1) / h_mcu_size;
 164         unsigned mcu_height_blocks = (dinfo.output_height + v_mcu_size - 1) / v_mcu_size;
 165
 166         unsigned luma_width_blocks = mcu_width_blocks * dinfo.comp_info[0].h_samp_factor;
 167         unsigned chroma_width_blocks = mcu_width_blocks * dinfo.comp_info[1].h_samp_factor;
 168         unsigned luma_height_blocks = mcu_height_blocks * dinfo.comp_info[0].v_samp_factor;
 169         unsigned chroma_height_blocks = mcu_height_blocks * dinfo.comp_info[1].v_samp_factor;
 170
 171         // TODO: Decode into a PBO.
 172         frame->y.reset(new uint8_t[luma_width_blocks * luma_height_blocks * DCTSIZE2]);
 173         frame->cb.reset(new uint8_t[chroma_width_blocks * chroma_height_blocks * DCTSIZE2]);
 174         frame->cr.reset(new uint8_t[chroma_width_blocks * chroma_height_blocks * DCTSIZE2]);
 175         frame->pitch_y = luma_width_blocks * DCTSIZE;
 176         frame->pitch_chroma = chroma_width_blocks * DCTSIZE;
 177
 178         if (!error_mgr.run([&dinfo, &frame, v_mcu_size, mcu_height_blocks] {
 179                     JSAMPROW yptr[v_mcu_size], cbptr[v_mcu_size], crptr[v_mcu_size];
 180                     JSAMPARRAY data[3] = { yptr, cbptr, crptr };
 181                     for (unsigned y = 0; y < mcu_height_blocks; ++y) {
 182                             // NOTE: The last elements of cbptr/crptr will be unused for vertically subsampled chroma.
 183                             for (unsigned yy = 0; yy < v_mcu_size; ++yy) {
 184                                     yptr[yy] = frame->y.get() + (y * DCTSIZE * dinfo.max_v_samp_factor + yy) * frame->pitch_y;
 185                                     cbptr[yy] = frame->cb.get() + (y * DCTSIZE * dinfo.comp_info[1].v_samp_factor + yy) * frame->pitch_chroma;
 186                                     crptr[yy] = frame->cr.get() + (y * DCTSIZE * dinfo.comp_info[1].v_samp_factor + yy) * frame->pitch_chroma;
 187                             }
 188
 189                             jpeg_read_raw_data(&dinfo, data, v_mcu_size);
 190                     }
 191
 192                     (void)jpeg_finish_decompress(&dinfo);
 193             })) {
 194                 return get_black_frame();
 195         }
 196
 197         ++metric_jpeg_software_decode_frames;
 198         return frame;
 199 }
 200
 201 void prune_cache()
 202 {
 203         // Assumes cache_mu is held.
 204         int64_t bytes_still_to_remove = cache_bytes_used - (size_t(CACHE_SIZE_MB) * 1024 * 1024) * 9 / 10;
 205         if (bytes_still_to_remove <= 0)
 206                 return;
 207
 208         vector<pair<size_t, size_t>> lru_timestamps_and_size;
 209         for (const auto &key_and_value : cache) {
 210                 lru_timestamps_and_size.emplace_back(
 211                         key_and_value.second.last_used,
 212                         frame_size(*key_and_value.second.frame));
 213         }
 214         sort(lru_timestamps_and_size.begin(), lru_timestamps_and_size.end());
 215
 216         // Remove the oldest ones until we are below 90% of the cache used.
 217         size_t lru_cutoff_point = 0;
 218         for (const pair<size_t, size_t> &it : lru_timestamps_and_size) {
 219                 lru_cutoff_point = it.first;
 220                 bytes_still_to_remove -= it.second;
 221                 if (bytes_still_to_remove <= 0)
 222                         break;
 223         }
 224
 225         for (auto it = cache.begin(); it != cache.end();) {
 226                 if (it->second.last_used <= lru_cutoff_point) {
 227                         cache_bytes_used -= frame_size(*it->second.frame);
 228                         metric_jpeg_cache_used_bytes = cache_bytes_used;
 229                         it = cache.erase(it);
 230                 } else {
 231                         ++it;
 232                 }
 233         }
 234 }
 235
 236 shared_ptr<Frame> decode_jpeg_with_cache(FrameOnDisk frame_spec, CacheMissBehavior cache_miss_behavior, FrameReader *frame_reader, bool *did_decode)
 237 {
 238         *did_decode = false;
 239         {
 240                 lock_guard<mutex> lock(cache_mu);
 241                 auto it = cache.find(frame_spec);
 242                 if (it != cache.end()) {
 243                         ++metric_jpeg_cache_hit_frames;
 244                         it->second.last_used = event_counter++;
 245                         return it->second.frame;
 246                 }
 247         }
 248
 249         if (cache_miss_behavior == RETURN_NULLPTR_IF_NOT_IN_CACHE) {
 250                 ++metric_jpeg_cache_given_up_frames;
 251                 return nullptr;
 252         }
 253
 254         ++metric_jpeg_cache_miss_frames;
 255
 256         *did_decode = true;
 257         shared_ptr<Frame> frame = decode_jpeg(frame_reader->read_frame(frame_spec));
 258
 259         lock_guard<mutex> lock(cache_mu);
 260         cache_bytes_used += frame_size(*frame);
 261         metric_jpeg_cache_used_bytes = cache_bytes_used;
 262         cache[frame_spec] = LRUFrame{ frame, event_counter++ };
 263
 264         if (cache_bytes_used > size_t(CACHE_SIZE_MB) * 1024 * 1024) {
 265                 prune_cache();
 266         }
 267         return frame;
 268 }
 269
 270 void JPEGFrameView::jpeg_decoder_thread_func()
 271 {
 272         size_t num_decoded = 0, num_dropped = 0;
 273
 274         pthread_setname_np(pthread_self(), "JPEGDecoder");
 275         while (!should_quit.load()) {
 276                 PendingDecode decode;
 277                 CacheMissBehavior cache_miss_behavior = DECODE_IF_NOT_IN_CACHE;
 278                 {
 279                         unique_lock<mutex> lock(cache_mu);  // TODO: Perhaps under another lock?
 280                         any_pending_decodes.wait(lock, [] {
 281                                 return !pending_decodes.empty() || should_quit.load();
 282                         });
 283                         if (should_quit.load())
 284                                 break;
 285                         decode = pending_decodes.front();
 286                         pending_decodes.pop_front();
 287
 288                         size_t num_pending = 0;
 289                         for (const PendingDecode &other_decode : pending_decodes) {
 290                                 if (other_decode.destination == decode.destination) {
 291                                         ++num_pending;
 292                                 }
 293                         }
 294                         if (num_pending > 3) {
 295                                 cache_miss_behavior = RETURN_NULLPTR_IF_NOT_IN_CACHE;
 296                         }
 297                 }
 298
 299                 if (decode.frame != nullptr) {
 300                         // Already decoded, so just show it.
 301                         decode.destination->setDecodedFrame(decode.frame, nullptr, 1.0f);
 302                         continue;
 303                 }
 304
 305                 shared_ptr<Frame> primary_frame, secondary_frame;
 306                 bool drop = false;
 307                 for (int subframe_idx = 0; subframe_idx < 2; ++subframe_idx) {
 308                         const FrameOnDisk &frame_spec = (subframe_idx == 0 ? decode.primary : decode.secondary);
 309                         if (frame_spec.pts == -1) {
 310                                 // No secondary frame.
 311                                 continue;
 312                         }
 313
 314                         bool found_in_cache;
 315                         shared_ptr<Frame> frame = decode_jpeg_with_cache(frame_spec, cache_miss_behavior, &decode.destination->frame_reader, &found_in_cache);
 316
 317                         if (frame == nullptr) {
 318                                 assert(cache_miss_behavior == RETURN_NULLPTR_IF_NOT_IN_CACHE);
 319                                 drop = true;
 320                                 break;
 321                         }
 322
 323                         if (!found_in_cache) {
 324                                 ++num_decoded;
 325                                 if (num_decoded % 1000 == 0) {
 326                                         fprintf(stderr, "Decoded %zu images, dropped %zu (%.2f%% dropped)\n",
 327                                                 num_decoded, num_dropped, (100.0 * num_dropped) / (num_decoded + num_dropped));
 328                                 }
 329                         }
 330                         if (subframe_idx == 0) {
 331                                 primary_frame = std::move(frame);
 332                         } else {
 333                                 secondary_frame = std::move(frame);
 334                         }
 335                 }
 336                 if (drop) {
 337                         ++num_dropped;
 338                         continue;
 339                 }
 340
 341                 // TODO: Could we get jitter between non-interpolated and interpolated frames here?
 342                 decode.destination->setDecodedFrame(primary_frame, secondary_frame, decode.fade_alpha);
 343         }
 344 }
 345
 346 void JPEGFrameView::shutdown()
 347 {
 348         any_pending_decodes.notify_all();
 349         jpeg_decoder_thread.join();
 350 }
 351
 352 JPEGFrameView::JPEGFrameView(QWidget *parent)
 353         : QGLWidget(parent, global_share_widget)
 354 {
 355         call_once(jpeg_metrics_inited, [] {
 356                 global_metrics.add("jpeg_cache_used_bytes", &metric_jpeg_cache_used_bytes, Metrics::TYPE_GAUGE);
 357                 global_metrics.add("jpeg_cache_limit_bytes", &metric_jpeg_cache_limit_bytes, Metrics::TYPE_GAUGE);
 358                 global_metrics.add("jpeg_cache_frames", { { "action", "given_up" } }, &metric_jpeg_cache_given_up_frames);
 359                 global_metrics.add("jpeg_cache_frames", { { "action", "hit" } }, &metric_jpeg_cache_hit_frames);
 360                 global_metrics.add("jpeg_cache_frames", { { "action", "miss" } }, &metric_jpeg_cache_miss_frames);
 361                 global_metrics.add("jpeg_decode_frames", { { "decoder", "software" }, { "result", "decode" } }, &metric_jpeg_software_decode_frames);
 362                 global_metrics.add("jpeg_decode_frames", { { "decoder", "software" }, { "result", "fail" } }, &metric_jpeg_software_fail_frames);
 363                 global_metrics.add("jpeg_decode_frames", { { "decoder", "vaapi" }, { "result", "decode" } }, &metric_jpeg_vaapi_decode_frames);
 364                 global_metrics.add("jpeg_decode_frames", { { "decoder", "vaapi" }, { "result", "fail" } }, &metric_jpeg_vaapi_fail_frames);
 365         });
 366 }
 367
 368 void JPEGFrameView::setFrame(unsigned stream_idx, FrameOnDisk frame, FrameOnDisk secondary_frame, float fade_alpha)
 369 {
 370         current_stream_idx = stream_idx;  // TODO: Does this interact with fades?
 371
 372         lock_guard<mutex> lock(cache_mu);
 373         PendingDecode decode;
 374         decode.primary = frame;
 375         decode.secondary = secondary_frame;
 376         decode.fade_alpha = fade_alpha;
 377         decode.destination = this;
 378         pending_decodes.push_back(decode);
 379         any_pending_decodes.notify_all();
 380 }
 381
 382 void JPEGFrameView::setFrame(shared_ptr<Frame> frame)
 383 {
 384         lock_guard<mutex> lock(cache_mu);
 385         PendingDecode decode;
 386         decode.frame = std::move(frame);
 387         decode.destination = this;
 388         pending_decodes.push_back(decode);
 389         any_pending_decodes.notify_all();
 390 }
 391
 392 ResourcePool *resource_pool = nullptr;
 393
 394 void JPEGFrameView::initializeGL()
 395 {
 396         glDisable(GL_BLEND);
 397         glDisable(GL_DEPTH_TEST);
 398         check_error();
 399
 400         static once_flag once;
 401         call_once(once, [] {
 402                 resource_pool = new ResourcePool;
 403                 jpeg_decoder_thread = std::thread(jpeg_decoder_thread_func);
 404         });
 405
 406         ycbcr_converter.reset(new YCbCrConverter(YCbCrConverter::OUTPUT_TO_RGBA, resource_pool));
 407
 408         ImageFormat inout_format;
 409         inout_format.color_space = COLORSPACE_sRGB;
 410         inout_format.gamma_curve = GAMMA_sRGB;
 411
 412         overlay_chain.reset(new EffectChain(overlay_base_width, overlay_base_height, resource_pool));
 413         overlay_input = (movit::FlatInput *)overlay_chain->add_input(new FlatInput(inout_format, FORMAT_GRAYSCALE, GL_UNSIGNED_BYTE, overlay_base_width, overlay_base_height));
 414
 415         overlay_chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
 416         overlay_chain->finalize();
 417 }
 418
 419 void JPEGFrameView::resizeGL(int width, int height)
 420 {
 421         check_error();
 422         glViewport(0, 0, width, height);
 423         check_error();
 424
 425         // Save these, as width() and height() will lie with DPI scaling.
 426         gl_width = width;
 427         gl_height = height;
 428 }
 429
 430 void JPEGFrameView::paintGL()
 431 {
 432         glViewport(0, 0, gl_width, gl_height);
 433         if (current_frame == nullptr) {
 434                 glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
 435                 glClear(GL_COLOR_BUFFER_BIT);
 436                 return;
 437         }
 438
 439         check_error();
 440         current_chain->render_to_screen();
 441
 442         if (overlay_image != nullptr) {
 443                 if (overlay_input_needs_refresh) {
 444                         overlay_input->set_width(overlay_width);
 445                         overlay_input->set_height(overlay_height);
 446                         overlay_input->set_pixel_data(overlay_image->bits());
 447                 }
 448                 glViewport(gl_width - overlay_width, 0, overlay_width, overlay_height);
 449                 overlay_chain->render_to_screen();
 450         }
 451 }
 452
 453 namespace {
 454
 455 }  // namespace
 456
 457 void JPEGFrameView::setDecodedFrame(shared_ptr<Frame> frame, shared_ptr<Frame> secondary_frame, float fade_alpha)
 458 {
 459         post_to_main_thread([this, frame, secondary_frame, fade_alpha] {
 460                 current_frame = frame;
 461                 current_secondary_frame = secondary_frame;
 462
 463                 if (secondary_frame != nullptr) {
 464                         current_chain = ycbcr_converter->prepare_chain_for_fade(frame, secondary_frame, fade_alpha);
 465                 } else {
 466                         current_chain = ycbcr_converter->prepare_chain_for_conversion(frame);
 467                 }
 468                 update();
 469         });
 470 }
 471
 472 void JPEGFrameView::mousePressEvent(QMouseEvent *event)
 473 {
 474         if (event->type() == QEvent::MouseButtonPress && event->button() == Qt::LeftButton) {
 475                 emit clicked();
 476         }
 477 }
 478
 479 void JPEGFrameView::set_overlay(const string &text)
 480 {
 481         if (text.empty()) {
 482                 overlay_image.reset();
 483                 return;
 484         }
 485
 486         float dpr = QGuiApplication::primaryScreen()->devicePixelRatio();
 487         overlay_width = lrint(overlay_base_width * dpr);
 488         overlay_height = lrint(overlay_base_height * dpr);
 489
 490         overlay_image.reset(new QImage(overlay_width, overlay_height, QImage::Format_Grayscale8));
 491         overlay_image->setDevicePixelRatio(dpr);
 492         overlay_image->fill(0);
 493         QPainter painter(overlay_image.get());
 494
 495         painter.setPen(Qt::white);
 496         QFont font = painter.font();
 497         font.setPointSize(12);
 498         painter.setFont(font);
 499
 500         painter.drawText(QRectF(0, 0, overlay_base_width, overlay_base_height), Qt::AlignCenter, QString::fromStdString(text));
 501
 502         // Don't refresh immediately; we might not have an OpenGL context here.
 503         overlay_input_needs_refresh = true;
 504 }
 505
 506 shared_ptr<Frame> get_black_frame()
 507 {
 508         static shared_ptr<Frame> black_frame;
 509         static once_flag flag;
 510         call_once(flag, [] {
 511                 black_frame.reset(new Frame);
 512                 black_frame->y.reset(new uint8_t[global_flags.width * global_flags.height]);
 513                 black_frame->cb.reset(new uint8_t[(global_flags.width / 2) * (global_flags.height / 2)]);
 514                 black_frame->cr.reset(new uint8_t[(global_flags.width / 2) * (global_flags.height / 2)]);
 515                 black_frame->width = global_flags.width;
 516                 black_frame->height = global_flags.height;
 517                 black_frame->chroma_subsampling_x = 2;
 518                 black_frame->chroma_subsampling_y = 2;
 519                 black_frame->pitch_y = global_flags.width;
 520                 black_frame->pitch_chroma = global_flags.width / 2;
 521         });
 522         ++metric_jpeg_software_fail_frames;
 523         return black_frame;
 524 }