remoting/codec/video_encoder_vpx.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "remoting/codec/video_encoder_vpx.h"
   6
   7 #include "base/bind.h"
   8 #include "base/command_line.h"
   9 #include "base/logging.h"
  10 #include "base/sys_info.h"
  11 #include "remoting/base/util.h"
  12 #include "remoting/proto/video.pb.h"
  13 #include "third_party/libyuv/include/libyuv/convert_from_argb.h"
  14 #include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
  15 #include "third_party/webrtc/modules/desktop_capture/desktop_geometry.h"
  16 #include "third_party/webrtc/modules/desktop_capture/desktop_region.h"
  17
  18 extern "C" {
  19 #define VPX_CODEC_DISABLE_COMPAT 1
  20 #include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
  21 #include "third_party/libvpx/source/libvpx/vpx/vp8cx.h"
  22 }
  23
  24 namespace remoting {
  25
  26 namespace {
  27
  28 // Name of command-line flag to enable VP9 to use I444 by default.
  29 const char kEnableI444SwitchName[] = "enable-i444";
  30
  31 // Number of bytes in an RGBx pixel.
  32 const int kBytesPerRgbPixel = 4;
  33
  34 // Defines the dimension of a macro block. This is used to compute the active
  35 // map for the encoder.
  36 const int kMacroBlockSize = 16;
  37
  38 // Magic encoder profile numbers for I420 and I444 input formats.
  39 const int kVp9I420ProfileNumber = 0;
  40 const int kVp9I444ProfileNumber = 1;
  41
  42 void SetCommonCodecParameters(vpx_codec_enc_cfg_t* config,
  43                               const webrtc::DesktopSize& size) {
  44   // Use millisecond granularity time base.
  45   config->g_timebase.num = 1;
  46   config->g_timebase.den = 1000;
  47
  48   // Adjust default target bit-rate to account for actual desktop size.
  49   config->rc_target_bitrate = size.width() * size.height() *
  50       config->rc_target_bitrate / config->g_w / config->g_h;
  51
  52   config->g_w = size.width();
  53   config->g_h = size.height();
  54   config->g_pass = VPX_RC_ONE_PASS;
  55
  56   // Start emitting packets immediately.
  57   config->g_lag_in_frames = 0;
  58
  59   // Since the transport layer is reliable, keyframes should not be necessary.
  60   // However, due to crbug.com/440223, decoding fails after 30,000 non-key
  61   // frames, so take the hit of an "unnecessary" key-frame every 10,000 frames.
  62   config->kf_min_dist = 10000;
  63   config->kf_max_dist = 10000;
  64
  65   // Using 2 threads gives a great boost in performance for most systems with
  66   // adequate processing power. NB: Going to multiple threads on low end
  67   // windows systems can really hurt performance.
  68   // http://crbug.com/99179
  69   config->g_threads = (base::SysInfo::NumberOfProcessors() > 2) ? 2 : 1;
  70 }
  71
  72 void SetVp8CodecParameters(vpx_codec_enc_cfg_t* config,
  73                            const webrtc::DesktopSize& size) {
  74   SetCommonCodecParameters(config, size);
  75
  76   // Value of 2 means using the real time profile. This is basically a
  77   // redundant option since we explicitly select real time mode when doing
  78   // encoding.
  79   config->g_profile = 2;
  80
  81   // Clamping the quantizer constrains the worst-case quality and CPU usage.
  82   config->rc_min_quantizer = 20;
  83   config->rc_max_quantizer = 30;
  84 }
  85
  86 void SetVp9CodecParameters(vpx_codec_enc_cfg_t* config,
  87                            const webrtc::DesktopSize& size,
  88                            bool lossless_color,
  89                            bool lossless_encode) {
  90   SetCommonCodecParameters(config, size);
  91
  92   // Configure VP9 for I420 or I444 source frames.
  93   config->g_profile =
  94       lossless_color ? kVp9I444ProfileNumber : kVp9I420ProfileNumber;
  95
  96   if (lossless_encode) {
  97     // Disable quantization entirely, putting the encoder in "lossless" mode.
  98     config->rc_min_quantizer = 0;
  99     config->rc_max_quantizer = 0;
 100   } else {
 101     // Lossy encode using the same settings as for VP8.
 102     config->rc_min_quantizer = 20;
 103     config->rc_max_quantizer = 30;
 104   }
 105 }
 106
 107 void SetVp8CodecOptions(vpx_codec_ctx_t* codec) {
 108   // CPUUSED of 16 will have the smallest CPU load. This turns off sub-pixel
 109   // motion search.
 110   vpx_codec_err_t ret = vpx_codec_control(codec, VP8E_SET_CPUUSED, 16);
 111   DCHECK_EQ(VPX_CODEC_OK, ret) << "Failed to set CPUUSED";
 112
 113   // Use the lowest level of noise sensitivity so as to spend less time
 114   // on motion estimation and inter-prediction mode.
 115   ret = vpx_codec_control(codec, VP8E_SET_NOISE_SENSITIVITY, 0);
 116   DCHECK_EQ(VPX_CODEC_OK, ret) << "Failed to set noise sensitivity";
 117 }
 118
 119 void SetVp9CodecOptions(vpx_codec_ctx_t* codec, bool lossless_encode) {
 120   // Request the lowest-CPU usage that VP9 supports, which depends on whether
 121   // we are encoding lossy or lossless.
 122   // Note that this is configured via the same parameter as for VP8.
 123   int cpu_used = lossless_encode ? 5 : 6;
 124   vpx_codec_err_t ret = vpx_codec_control(codec, VP8E_SET_CPUUSED, cpu_used);
 125   DCHECK_EQ(VPX_CODEC_OK, ret) << "Failed to set CPUUSED";
 126
 127   // Use the lowest level of noise sensitivity so as to spend less time
 128   // on motion estimation and inter-prediction mode.
 129   ret = vpx_codec_control(codec, VP9E_SET_NOISE_SENSITIVITY, 0);
 130   DCHECK_EQ(VPX_CODEC_OK, ret) << "Failed to set noise sensitivity";
 131
 132   // Configure the codec to tune it for screen media.
 133   ret = vpx_codec_control(
 134       codec, VP9E_SET_TUNE_CONTENT, VP9E_CONTENT_SCREEN);
 135   DCHECK_EQ(VPX_CODEC_OK, ret) << "Failed to set screen content mode";
 136 }
 137
 138 void FreeImageIfMismatched(bool use_i444,
 139                            const webrtc::DesktopSize& size,
 140                            scoped_ptr<vpx_image_t>* out_image,
 141                            scoped_ptr<uint8[]>* out_image_buffer) {
 142   if (*out_image) {
 143     const vpx_img_fmt_t desired_fmt =
 144         use_i444 ? VPX_IMG_FMT_I444 : VPX_IMG_FMT_I420;
 145     if (!size.equals(webrtc::DesktopSize((*out_image)->w, (*out_image)->h)) ||
 146         (*out_image)->fmt != desired_fmt) {
 147       out_image_buffer->reset();
 148       out_image->reset();
 149     }
 150   }
 151 }
 152
 153 void CreateImage(bool use_i444,
 154                  const webrtc::DesktopSize& size,
 155                  scoped_ptr<vpx_image_t>* out_image,
 156                  scoped_ptr<uint8[]>* out_image_buffer) {
 157   DCHECK(!size.is_empty());
 158   DCHECK(!*out_image_buffer);
 159   DCHECK(!*out_image);
 160
 161   scoped_ptr<vpx_image_t> image(new vpx_image_t());
 162   memset(image.get(), 0, sizeof(vpx_image_t));
 163
 164   // libvpx seems to require both to be assigned.
 165   image->d_w = size.width();
 166   image->w = size.width();
 167   image->d_h = size.height();
 168   image->h = size.height();
 169
 170   // libvpx should derive chroma shifts from|fmt| but currently has a bug:
 171   // https://code.google.com/p/webm/issues/detail?id=627
 172   if (use_i444) {
 173     image->fmt = VPX_IMG_FMT_I444;
 174     image->x_chroma_shift = 0;
 175     image->y_chroma_shift = 0;
 176   } else { // I420
 177     image->fmt = VPX_IMG_FMT_YV12;
 178     image->x_chroma_shift = 1;
 179     image->y_chroma_shift = 1;
 180   }
 181
 182   // libyuv's fast-path requires 16-byte aligned pointers and strides, so pad
 183   // the Y, U and V planes' strides to multiples of 16 bytes.
 184   const int y_stride = ((image->w - 1) & ~15) + 16;
 185   const int uv_unaligned_stride = y_stride >> image->x_chroma_shift;
 186   const int uv_stride = ((uv_unaligned_stride - 1) & ~15) + 16;
 187
 188   // libvpx accesses the source image in macro blocks, and will over-read
 189   // if the image is not padded out to the next macroblock: crbug.com/119633.
 190   // Pad the Y, U and V planes' height out to compensate.
 191   // Assuming macroblocks are 16x16, aligning the planes' strides above also
 192   // macroblock aligned them.
 193   static_assert(kMacroBlockSize == 16, "macroblock_size_not_16");
 194   const int y_rows = ((image->h - 1) & ~(kMacroBlockSize-1)) + kMacroBlockSize;
 195   const int uv_rows = y_rows >> image->y_chroma_shift;
 196
 197   // Allocate a YUV buffer large enough for the aligned data & padding.
 198   const int buffer_size = y_stride * y_rows + 2*uv_stride * uv_rows;
 199   scoped_ptr<uint8[]> image_buffer(new uint8[buffer_size]);
 200
 201   // Reset image value to 128 so we just need to fill in the y plane.
 202   memset(image_buffer.get(), 128, buffer_size);
 203
 204   // Fill in the information for |image_|.
 205   unsigned char* uchar_buffer =
 206       reinterpret_cast<unsigned char*>(image_buffer.get());
 207   image->planes[0] = uchar_buffer;
 208   image->planes[1] = image->planes[0] + y_stride * y_rows;
 209   image->planes[2] = image->planes[1] + uv_stride * uv_rows;
 210   image->stride[0] = y_stride;
 211   image->stride[1] = uv_stride;
 212   image->stride[2] = uv_stride;
 213
 214   *out_image = image.Pass();
 215   *out_image_buffer = image_buffer.Pass();
 216 }
 217
 218 } // namespace
 219
 220 // static
 221 scoped_ptr<VideoEncoderVpx> VideoEncoderVpx::CreateForVP8() {
 222   return make_scoped_ptr(new VideoEncoderVpx(false));
 223 }
 224
 225 // static
 226 scoped_ptr<VideoEncoderVpx> VideoEncoderVpx::CreateForVP9() {
 227   return make_scoped_ptr(new VideoEncoderVpx(true));
 228 }
 229
 230 VideoEncoderVpx::~VideoEncoderVpx() {}
 231
 232 void VideoEncoderVpx::SetLosslessEncode(bool want_lossless) {
 233   if (use_vp9_ && (want_lossless != lossless_encode_)) {
 234     lossless_encode_ = want_lossless;
 235     if (codec_)
 236       Configure(webrtc::DesktopSize(codec_->config.enc->g_w,
 237                                     codec_->config.enc->g_h));
 238   }
 239 }
 240
 241 void VideoEncoderVpx::SetLosslessColor(bool want_lossless) {
 242   if (use_vp9_ && (want_lossless != lossless_color_)) {
 243     lossless_color_ = want_lossless;
 244     // TODO(wez): Switch to ConfigureCodec() path once libvpx supports it.
 245     // See https://code.google.com/p/webm/issues/detail?id=913.
 246     //if (codec_)
 247     //  Configure(webrtc::DesktopSize(codec_->config.enc->g_w,
 248     //                                codec_->config.enc->g_h));
 249     codec_.reset();
 250   }
 251 }
 252
 253 scoped_ptr<VideoPacket> VideoEncoderVpx::Encode(
 254     const webrtc::DesktopFrame& frame) {
 255   DCHECK_LE(32, frame.size().width());
 256   DCHECK_LE(32, frame.size().height());
 257
 258   base::TimeTicks encode_start_time = base::TimeTicks::Now();
 259
 260   // Create or reconfigure the codec to match the size of |frame|.
 261   if (!codec_ ||
 262       (image_ &&
 263        !frame.size().equals(webrtc::DesktopSize(image_->w, image_->h)))) {
 264     Configure(frame.size());
 265   }
 266
 267   // Convert the updated capture data ready for encode.
 268   webrtc::DesktopRegion updated_region;
 269   PrepareImage(frame, &updated_region);
 270
 271   // Update active map based on updated region.
 272   PrepareActiveMap(updated_region);
 273
 274   // Apply active map to the encoder.
 275   vpx_active_map_t act_map;
 276   act_map.rows = active_map_height_;
 277   act_map.cols = active_map_width_;
 278   act_map.active_map = active_map_.get();
 279   if (vpx_codec_control(codec_.get(), VP8E_SET_ACTIVEMAP, &act_map)) {
 280     LOG(ERROR) << "Unable to apply active map";
 281   }
 282
 283   // Do the actual encoding.
 284   int timestamp = (encode_start_time - timestamp_base_).InMilliseconds();
 285   vpx_codec_err_t ret = vpx_codec_encode(
 286       codec_.get(), image_.get(), timestamp, 1, 0, VPX_DL_REALTIME);
 287   DCHECK_EQ(ret, VPX_CODEC_OK)
 288       << "Encoding error: " << vpx_codec_err_to_string(ret) << "\n"
 289       << "Details: " << vpx_codec_error(codec_.get()) << "\n"
 290       << vpx_codec_error_detail(codec_.get());
 291
 292   // Read the encoded data.
 293   vpx_codec_iter_t iter = NULL;
 294   bool got_data = false;
 295
 296   // TODO(hclam): Make sure we get exactly one frame from the packet.
 297   // TODO(hclam): We should provide the output buffer to avoid one copy.
 298   scoped_ptr<VideoPacket> packet(
 299       helper_.CreateVideoPacketWithUpdatedRegion(frame, updated_region));
 300   packet->mutable_format()->set_encoding(VideoPacketFormat::ENCODING_VP8);
 301
 302   while (!got_data) {
 303     const vpx_codec_cx_pkt_t* vpx_packet =
 304         vpx_codec_get_cx_data(codec_.get(), &iter);
 305     if (!vpx_packet)
 306       continue;
 307
 308     switch (vpx_packet->kind) {
 309       case VPX_CODEC_CX_FRAME_PKT:
 310         got_data = true;
 311         packet->set_data(vpx_packet->data.frame.buf, vpx_packet->data.frame.sz);
 312         break;
 313       default:
 314         break;
 315     }
 316   }
 317
 318   // Note the time taken to encode the pixel data.
 319   packet->set_encode_time_ms(
 320       (base::TimeTicks::Now() - encode_start_time).InMillisecondsRoundedUp());
 321
 322   return packet.Pass();
 323 }
 324
 325 VideoEncoderVpx::VideoEncoderVpx(bool use_vp9)
 326     : use_vp9_(use_vp9),
 327       lossless_encode_(false),
 328       lossless_color_(false),
 329       active_map_width_(0),
 330       active_map_height_(0) {
 331   if (use_vp9_) {
 332     // Use I444 colour space, by default, if specified on the command-line.
 333     if (base::CommandLine::ForCurrentProcess()->HasSwitch(
 334             kEnableI444SwitchName)) {
 335       SetLosslessColor(true);
 336     }
 337   }
 338 }
 339
 340 void VideoEncoderVpx::Configure(const webrtc::DesktopSize& size) {
 341   DCHECK(use_vp9_ || !lossless_color_);
 342   DCHECK(use_vp9_ || !lossless_encode_);
 343
 344   // Tear down |image_| if it no longer matches the size and color settings.
 345   // PrepareImage() will then create a new buffer of the required dimensions if
 346   // |image_| is not allocated.
 347   FreeImageIfMismatched(lossless_color_, size, &image_, &image_buffer_);
 348
 349   // Initialize active map.
 350   active_map_width_ = (size.width() + kMacroBlockSize - 1) / kMacroBlockSize;
 351   active_map_height_ = (size.height() + kMacroBlockSize - 1) / kMacroBlockSize;
 352   active_map_.reset(new uint8[active_map_width_ * active_map_height_]);
 353
 354   // TODO(wez): Remove this hack once VPX can handle frame size reconfiguration.
 355   // See https://code.google.com/p/webm/issues/detail?id=912.
 356   if (codec_) {
 357     // If the frame size has changed then force re-creation of the codec.
 358     if (codec_->config.enc->g_w != static_cast<unsigned int>(size.width()) ||
 359         codec_->config.enc->g_h != static_cast<unsigned int>(size.height())) {
 360       codec_.reset();
 361     }
 362   }
 363
 364   // (Re)Set the base for frame timestamps if the codec is being (re)created.
 365   if (!codec_) {
 366     timestamp_base_ = base::TimeTicks::Now();
 367   }
 368
 369   // Fetch a default configuration for the desired codec.
 370   const vpx_codec_iface_t* interface =
 371       use_vp9_ ? vpx_codec_vp9_cx() : vpx_codec_vp8_cx();
 372   vpx_codec_enc_cfg_t config;
 373   vpx_codec_err_t ret = vpx_codec_enc_config_default(interface, &config, 0);
 374   DCHECK_EQ(VPX_CODEC_OK, ret) << "Failed to fetch default configuration";
 375
 376   // Customize the default configuration to our needs.
 377   if (use_vp9_) {
 378     SetVp9CodecParameters(&config, size, lossless_color_, lossless_encode_);
 379   } else {
 380     SetVp8CodecParameters(&config, size);
 381   }
 382
 383   // Initialize or re-configure the codec with the custom configuration.
 384   if (!codec_) {
 385     codec_.reset(new vpx_codec_ctx_t);
 386     ret = vpx_codec_enc_init(codec_.get(), interface, &config, 0);
 387     CHECK_EQ(VPX_CODEC_OK, ret) << "Failed to initialize codec";
 388   } else {
 389     ret = vpx_codec_enc_config_set(codec_.get(), &config);
 390     CHECK_EQ(VPX_CODEC_OK, ret) << "Failed to reconfigure codec";
 391   }
 392
 393   // Apply further customizations to the codec now it's initialized.
 394   if (use_vp9_) {
 395     SetVp9CodecOptions(codec_.get(), lossless_encode_);
 396   } else {
 397     SetVp8CodecOptions(codec_.get());
 398   }
 399 }
 400
 401 void VideoEncoderVpx::PrepareImage(const webrtc::DesktopFrame& frame,
 402                                    webrtc::DesktopRegion* updated_region) {
 403   if (frame.updated_region().is_empty()) {
 404     updated_region->Clear();
 405     return;
 406   }
 407
 408   updated_region->Clear();
 409   if (image_) {
 410     // Pad each rectangle to avoid the block-artefact filters in libvpx from
 411     // introducing artefacts; VP9 includes up to 8px either side, and VP8 up to
 412     // 3px, so unchanged pixels up to that far out may still be affected by the
 413     // changes in the updated region, and so must be listed in the active map.
 414     // After padding we align each rectangle to 16x16 active-map macroblocks.
 415     // This implicitly ensures all rects have even top-left coords, which is
 416     // is required by ConvertRGBToYUVWithRect().
 417     // TODO(wez): Do we still need 16x16 align, or is even alignment sufficient?
 418     int padding = use_vp9_ ? 8 : 3;
 419     for (webrtc::DesktopRegion::Iterator r(frame.updated_region());
 420          !r.IsAtEnd(); r.Advance()) {
 421       const webrtc::DesktopRect& rect = r.rect();
 422       updated_region->AddRect(AlignRect(webrtc::DesktopRect::MakeLTRB(
 423           rect.left() - padding, rect.top() - padding, rect.right() + padding,
 424           rect.bottom() + padding)));
 425     }
 426     DCHECK(!updated_region->is_empty());
 427
 428     // Clip back to the screen dimensions, in case they're not macroblock
 429     // aligned. The conversion routines don't require even width & height,
 430     // so this is safe even if the source dimensions are not even.
 431     updated_region->IntersectWith(
 432         webrtc::DesktopRect::MakeWH(image_->w, image_->h));
 433   } else {
 434     CreateImage(lossless_color_, frame.size(), &image_, &image_buffer_);
 435     updated_region->AddRect(webrtc::DesktopRect::MakeWH(image_->w, image_->h));
 436   }
 437
 438   // Convert the updated region to YUV ready for encoding.
 439   const uint8* rgb_data = frame.data();
 440   const int rgb_stride = frame.stride();
 441   const int y_stride = image_->stride[0];
 442   DCHECK_EQ(image_->stride[1], image_->stride[2]);
 443   const int uv_stride = image_->stride[1];
 444   uint8* y_data = image_->planes[0];
 445   uint8* u_data = image_->planes[1];
 446   uint8* v_data = image_->planes[2];
 447
 448   switch (image_->fmt) {
 449     case VPX_IMG_FMT_I444:
 450       for (webrtc::DesktopRegion::Iterator r(*updated_region); !r.IsAtEnd();
 451            r.Advance()) {
 452         const webrtc::DesktopRect& rect = r.rect();
 453         int rgb_offset = rgb_stride * rect.top() +
 454                          rect.left() * kBytesPerRgbPixel;
 455         int yuv_offset = uv_stride * rect.top() + rect.left();
 456         libyuv::ARGBToI444(rgb_data + rgb_offset, rgb_stride,
 457                            y_data + yuv_offset, y_stride,
 458                            u_data + yuv_offset, uv_stride,
 459                            v_data + yuv_offset, uv_stride,
 460                            rect.width(), rect.height());
 461       }
 462       break;
 463     case VPX_IMG_FMT_YV12:
 464       for (webrtc::DesktopRegion::Iterator r(*updated_region); !r.IsAtEnd();
 465            r.Advance()) {
 466         const webrtc::DesktopRect& rect = r.rect();
 467         int rgb_offset = rgb_stride * rect.top() +
 468                          rect.left() * kBytesPerRgbPixel;
 469         int y_offset = y_stride * rect.top() + rect.left();
 470         int uv_offset = uv_stride * rect.top() / 2 + rect.left() / 2;
 471         libyuv::ARGBToI420(rgb_data + rgb_offset, rgb_stride,
 472                            y_data + y_offset, y_stride,
 473                            u_data + uv_offset, uv_stride,
 474                            v_data + uv_offset, uv_stride,
 475                            rect.width(), rect.height());
 476       }
 477       break;
 478     default:
 479       NOTREACHED();
 480       break;
 481   }
 482 }
 483
 484 void VideoEncoderVpx::PrepareActiveMap(
 485     const webrtc::DesktopRegion& updated_region) {
 486   // Clear active map first.
 487   memset(active_map_.get(), 0, active_map_width_ * active_map_height_);
 488
 489   // Mark updated areas active.
 490   for (webrtc::DesktopRegion::Iterator r(updated_region); !r.IsAtEnd();
 491        r.Advance()) {
 492     const webrtc::DesktopRect& rect = r.rect();
 493     int left = rect.left() / kMacroBlockSize;
 494     int right = (rect.right() - 1) / kMacroBlockSize;
 495     int top = rect.top() / kMacroBlockSize;
 496     int bottom = (rect.bottom() - 1) / kMacroBlockSize;
 497     DCHECK_LT(right, active_map_width_);
 498     DCHECK_LT(bottom, active_map_height_);
 499
 500     uint8* map = active_map_.get() + top * active_map_width_;
 501     for (int y = top; y <= bottom; ++y) {
 502       for (int x = left; x <= right; ++x)
 503         map[x] = 1;
 504       map += active_map_width_;
 505     }
 506   }
 507 }
 508
 509 }  // namespace remoting