content/renderer/media/rtc_video_decoder.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 "content/renderer/media/rtc_video_decoder.h"
   6
   7 #include "base/bind.h"
   8 #include "base/logging.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/message_loop/message_loop_proxy.h"
  11 #include "base/metrics/histogram.h"
  12 #include "base/numerics/safe_conversions.h"
  13 #include "base/stl_util.h"
  14 #include "base/synchronization/waitable_event.h"
  15 #include "base/task_runner_util.h"
  16 #include "content/renderer/media/native_handle_impl.h"
  17 #include "gpu/command_buffer/common/mailbox_holder.h"
  18 #include "media/base/bind_to_current_loop.h"
  19 #include "media/filters/gpu_video_accelerator_factories.h"
  20 #include "third_party/skia/include/core/SkBitmap.h"
  21 #include "third_party/webrtc/common_video/interface/texture_video_frame.h"
  22 #include "third_party/webrtc/system_wrappers/interface/ref_count.h"
  23
  24 namespace content {
  25
  26 const int32 RTCVideoDecoder::ID_LAST = 0x3FFFFFFF;
  27 const int32 RTCVideoDecoder::ID_HALF = 0x20000000;
  28 const int32 RTCVideoDecoder::ID_INVALID = -1;
  29
  30 // Maximum number of concurrent VDA::Decode() operations RVD will maintain.
  31 // Higher values allow better pipelining in the GPU, but also require more
  32 // resources.
  33 static const size_t kMaxInFlightDecodes = 8;
  34
  35 // Size of shared-memory segments we allocate.  Since we reuse them we let them
  36 // be on the beefy side.
  37 static const size_t kSharedMemorySegmentBytes = 100 << 10;
  38
  39 // Maximum number of allocated shared-memory segments.
  40 static const int kMaxNumSharedMemorySegments = 16;
  41
  42 // Maximum number of pending WebRTC buffers that are waiting for the shared
  43 // memory. 10 seconds for 30 fps.
  44 static const size_t kMaxNumOfPendingBuffers = 300;
  45
  46 // A shared memory segment and its allocated size. This class has the ownership
  47 // of |shm|.
  48 class RTCVideoDecoder::SHMBuffer {
  49  public:
  50   SHMBuffer(scoped_ptr<base::SharedMemory> shm, size_t size);
  51   ~SHMBuffer();
  52   scoped_ptr<base::SharedMemory> const shm;
  53   const size_t size;
  54 };
  55
  56 RTCVideoDecoder::SHMBuffer::SHMBuffer(scoped_ptr<base::SharedMemory> shm,
  57                                       size_t size)
  58     : shm(shm.Pass()), size(size) {
  59 }
  60
  61 RTCVideoDecoder::SHMBuffer::~SHMBuffer() {
  62 }
  63
  64 RTCVideoDecoder::BufferData::BufferData(int32 bitstream_buffer_id,
  65                                         uint32_t timestamp,
  66                                         size_t size)
  67     : bitstream_buffer_id(bitstream_buffer_id),
  68       timestamp(timestamp),
  69       size(size) {}
  70
  71 RTCVideoDecoder::BufferData::BufferData() {}
  72
  73 RTCVideoDecoder::BufferData::~BufferData() {}
  74
  75 RTCVideoDecoder::RTCVideoDecoder(
  76     webrtc::VideoCodecType type,
  77     const scoped_refptr<media::GpuVideoAcceleratorFactories>& factories)
  78     : video_codec_type_(type),
  79       factories_(factories),
  80       decoder_texture_target_(0),
  81       next_picture_buffer_id_(0),
  82       state_(UNINITIALIZED),
  83       decode_complete_callback_(NULL),
  84       num_shm_buffers_(0),
  85       next_bitstream_buffer_id_(0),
  86       reset_bitstream_buffer_id_(ID_INVALID),
  87       weak_factory_(this) {
  88   DCHECK(!factories_->GetTaskRunner()->BelongsToCurrentThread());
  89 }
  90
  91 RTCVideoDecoder::~RTCVideoDecoder() {
  92   DVLOG(2) << "~RTCVideoDecoder";
  93   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
  94   DestroyVDA();
  95
  96   // Delete all shared memories.
  97   STLDeleteElements(&available_shm_segments_);
  98   STLDeleteValues(&bitstream_buffers_in_decoder_);
  99   STLDeleteContainerPairFirstPointers(decode_buffers_.begin(),
 100                                       decode_buffers_.end());
 101   decode_buffers_.clear();
 102
 103   // Delete WebRTC input buffers.
 104   for (std::deque<std::pair<webrtc::EncodedImage, BufferData> >::iterator it =
 105            pending_buffers_.begin();
 106        it != pending_buffers_.end();
 107        ++it) {
 108     delete[] it->first._buffer;
 109   }
 110 }
 111
 112 // static
 113 scoped_ptr<RTCVideoDecoder> RTCVideoDecoder::Create(
 114     webrtc::VideoCodecType type,
 115     const scoped_refptr<media::GpuVideoAcceleratorFactories>& factories) {
 116   scoped_ptr<RTCVideoDecoder> decoder;
 117   // Convert WebRTC codec type to media codec profile.
 118   media::VideoCodecProfile profile;
 119   switch (type) {
 120     case webrtc::kVideoCodecVP8:
 121       profile = media::VP8PROFILE_ANY;
 122       break;
 123     case webrtc::kVideoCodecH264:
 124       profile = media::H264PROFILE_MAIN;
 125       break;
 126     default:
 127       DVLOG(2) << "Video codec not supported:" << type;
 128       return decoder.Pass();
 129   }
 130
 131   base::WaitableEvent waiter(true, false);
 132   decoder.reset(new RTCVideoDecoder(type, factories));
 133   decoder->factories_->GetTaskRunner()->PostTask(
 134       FROM_HERE,
 135       base::Bind(&RTCVideoDecoder::CreateVDA,
 136                  base::Unretained(decoder.get()),
 137                  profile,
 138                  &waiter));
 139   waiter.Wait();
 140   // vda can be NULL if the codec is not supported.
 141   if (decoder->vda_ != NULL) {
 142     decoder->state_ = INITIALIZED;
 143   } else {
 144     factories->GetTaskRunner()->DeleteSoon(FROM_HERE, decoder.release());
 145   }
 146   return decoder.Pass();
 147 }
 148
 149 int32_t RTCVideoDecoder::InitDecode(const webrtc::VideoCodec* codecSettings,
 150                                     int32_t /*numberOfCores*/) {
 151   DVLOG(2) << "InitDecode";
 152   DCHECK_EQ(video_codec_type_, codecSettings->codecType);
 153   if (codecSettings->codecType == webrtc::kVideoCodecVP8 &&
 154       codecSettings->codecSpecific.VP8.feedbackModeOn) {
 155     LOG(ERROR) << "Feedback mode not supported";
 156     return RecordInitDecodeUMA(WEBRTC_VIDEO_CODEC_ERROR);
 157   }
 158
 159   base::AutoLock auto_lock(lock_);
 160   if (state_ == UNINITIALIZED || state_ == DECODE_ERROR) {
 161     LOG(ERROR) << "VDA is not initialized. state=" << state_;
 162     return RecordInitDecodeUMA(WEBRTC_VIDEO_CODEC_UNINITIALIZED);
 163   }
 164   // Create some shared memory if the queue is empty.
 165   if (available_shm_segments_.size() == 0) {
 166     factories_->GetTaskRunner()->PostTask(
 167         FROM_HERE,
 168         base::Bind(&RTCVideoDecoder::CreateSHM,
 169                    weak_factory_.GetWeakPtr(),
 170                    kMaxInFlightDecodes,
 171                    kSharedMemorySegmentBytes));
 172   }
 173   return RecordInitDecodeUMA(WEBRTC_VIDEO_CODEC_OK);
 174 }
 175
 176 int32_t RTCVideoDecoder::Decode(
 177     const webrtc::EncodedImage& inputImage,
 178     bool missingFrames,
 179     const webrtc::RTPFragmentationHeader* /*fragmentation*/,
 180     const webrtc::CodecSpecificInfo* /*codecSpecificInfo*/,
 181     int64_t /*renderTimeMs*/) {
 182   DVLOG(3) << "Decode";
 183
 184   base::AutoLock auto_lock(lock_);
 185
 186   if (state_ == UNINITIALIZED || decode_complete_callback_ == NULL) {
 187     LOG(ERROR) << "The decoder has not initialized.";
 188     return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
 189   }
 190
 191   if (state_ == DECODE_ERROR) {
 192     LOG(ERROR) << "Decoding error occurred.";
 193     return WEBRTC_VIDEO_CODEC_ERROR;
 194   }
 195
 196   if (missingFrames || !inputImage._completeFrame) {
 197     DLOG(ERROR) << "Missing or incomplete frames.";
 198     // Unlike the SW decoder in libvpx, hw decoder cannot handle broken frames.
 199     // Return an error to request a key frame.
 200     return WEBRTC_VIDEO_CODEC_ERROR;
 201   }
 202
 203   // Most platforms' VDA implementations support mid-stream resolution change
 204   // internally.  Platforms whose VDAs fail to support mid-stream resolution
 205   // change gracefully need to have their clients cover for them, and we do that
 206   // here.
 207 #ifdef ANDROID
 208   const bool kVDACanHandleMidstreamResize = false;
 209 #else
 210   const bool kVDACanHandleMidstreamResize = true;
 211 #endif
 212
 213   bool need_to_reset_for_midstream_resize = false;
 214   if (inputImage._frameType == webrtc::kKeyFrame) {
 215     DVLOG(2) << "Got key frame. size=" << inputImage._encodedWidth << "x"
 216              << inputImage._encodedHeight;
 217     gfx::Size prev_frame_size = frame_size_;
 218     frame_size_.SetSize(inputImage._encodedWidth, inputImage._encodedHeight);
 219     if (!kVDACanHandleMidstreamResize && !prev_frame_size.IsEmpty() &&
 220         prev_frame_size != frame_size_) {
 221       need_to_reset_for_midstream_resize = true;
 222     }
 223   } else if (IsFirstBufferAfterReset(next_bitstream_buffer_id_,
 224                                      reset_bitstream_buffer_id_)) {
 225     // TODO(wuchengli): VDA should handle it. Remove this when
 226     // http://crosbug.com/p/21913 is fixed.
 227     DVLOG(1) << "The first frame should be a key frame. Drop this.";
 228     return WEBRTC_VIDEO_CODEC_ERROR;
 229   }
 230
 231   // Create buffer metadata.
 232   BufferData buffer_data(next_bitstream_buffer_id_,
 233                          inputImage._timeStamp,
 234                          inputImage._length);
 235   // Mask against 30 bits, to avoid (undefined) wraparound on signed integer.
 236   next_bitstream_buffer_id_ = (next_bitstream_buffer_id_ + 1) & ID_LAST;
 237
 238   // If a shared memory segment is available, there are no pending buffers, and
 239   // this isn't a mid-stream resolution change, then send the buffer for decode
 240   // immediately. Otherwise, save the buffer in the queue for later decode.
 241   scoped_ptr<SHMBuffer> shm_buffer;
 242   if (!need_to_reset_for_midstream_resize && pending_buffers_.size() == 0)
 243     shm_buffer = GetSHM_Locked(inputImage._length);
 244   if (!shm_buffer) {
 245     if (!SaveToPendingBuffers_Locked(inputImage, buffer_data))
 246       return WEBRTC_VIDEO_CODEC_ERROR;
 247     if (need_to_reset_for_midstream_resize) {
 248       base::AutoUnlock auto_unlock(lock_);
 249       Reset();
 250     }
 251     return WEBRTC_VIDEO_CODEC_OK;
 252   }
 253
 254   SaveToDecodeBuffers_Locked(inputImage, shm_buffer.Pass(), buffer_data);
 255   factories_->GetTaskRunner()->PostTask(
 256       FROM_HERE,
 257       base::Bind(&RTCVideoDecoder::RequestBufferDecode,
 258                  weak_factory_.GetWeakPtr()));
 259   return WEBRTC_VIDEO_CODEC_OK;
 260 }
 261
 262 int32_t RTCVideoDecoder::RegisterDecodeCompleteCallback(
 263     webrtc::DecodedImageCallback* callback) {
 264   DVLOG(2) << "RegisterDecodeCompleteCallback";
 265   base::AutoLock auto_lock(lock_);
 266   decode_complete_callback_ = callback;
 267   return WEBRTC_VIDEO_CODEC_OK;
 268 }
 269
 270 int32_t RTCVideoDecoder::Release() {
 271   DVLOG(2) << "Release";
 272   // Do not destroy VDA because WebRTC can call InitDecode and start decoding
 273   // again.
 274   return Reset();
 275 }
 276
 277 int32_t RTCVideoDecoder::Reset() {
 278   DVLOG(2) << "Reset";
 279   base::AutoLock auto_lock(lock_);
 280   if (state_ == UNINITIALIZED) {
 281     LOG(ERROR) << "Decoder not initialized.";
 282     return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
 283   }
 284   if (next_bitstream_buffer_id_ != 0)
 285     reset_bitstream_buffer_id_ = next_bitstream_buffer_id_ - 1;
 286   else
 287     reset_bitstream_buffer_id_ = ID_LAST;
 288   // If VDA is already resetting, no need to request the reset again.
 289   if (state_ != RESETTING) {
 290     state_ = RESETTING;
 291     factories_->GetTaskRunner()->PostTask(
 292         FROM_HERE,
 293         base::Bind(&RTCVideoDecoder::ResetInternal,
 294                    weak_factory_.GetWeakPtr()));
 295   }
 296   return WEBRTC_VIDEO_CODEC_OK;
 297 }
 298
 299 void RTCVideoDecoder::ProvidePictureBuffers(uint32 count,
 300                                             const gfx::Size& size,
 301                                             uint32 texture_target) {
 302   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 303   DVLOG(3) << "ProvidePictureBuffers. texture_target=" << texture_target;
 304
 305   if (!vda_)
 306     return;
 307
 308   std::vector<uint32> texture_ids;
 309   std::vector<gpu::Mailbox> texture_mailboxes;
 310   decoder_texture_target_ = texture_target;
 311   if (!factories_->CreateTextures(count,
 312                                   size,
 313                                   &texture_ids,
 314                                   &texture_mailboxes,
 315                                   decoder_texture_target_)) {
 316     NotifyError(media::VideoDecodeAccelerator::PLATFORM_FAILURE);
 317     return;
 318   }
 319   DCHECK_EQ(count, texture_ids.size());
 320   DCHECK_EQ(count, texture_mailboxes.size());
 321
 322   std::vector<media::PictureBuffer> picture_buffers;
 323   for (size_t i = 0; i < texture_ids.size(); ++i) {
 324     picture_buffers.push_back(media::PictureBuffer(
 325         next_picture_buffer_id_++, size, texture_ids[i], texture_mailboxes[i]));
 326     bool inserted = assigned_picture_buffers_.insert(std::make_pair(
 327         picture_buffers.back().id(), picture_buffers.back())).second;
 328     DCHECK(inserted);
 329   }
 330   vda_->AssignPictureBuffers(picture_buffers);
 331 }
 332
 333 void RTCVideoDecoder::DismissPictureBuffer(int32 id) {
 334   DVLOG(3) << "DismissPictureBuffer. id=" << id;
 335   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 336
 337   std::map<int32, media::PictureBuffer>::iterator it =
 338       assigned_picture_buffers_.find(id);
 339   if (it == assigned_picture_buffers_.end()) {
 340     NOTREACHED() << "Missing picture buffer: " << id;
 341     return;
 342   }
 343
 344   media::PictureBuffer buffer_to_dismiss = it->second;
 345   assigned_picture_buffers_.erase(it);
 346
 347   if (!picture_buffers_at_display_.count(id)) {
 348     // We can delete the texture immediately as it's not being displayed.
 349     factories_->DeleteTexture(buffer_to_dismiss.texture_id());
 350     return;
 351   }
 352   // Not destroying a texture in display in |picture_buffers_at_display_|.
 353   // Postpone deletion until after it's returned to us.
 354 }
 355
 356 void RTCVideoDecoder::PictureReady(const media::Picture& picture) {
 357   DVLOG(3) << "PictureReady";
 358   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 359
 360   std::map<int32, media::PictureBuffer>::iterator it =
 361       assigned_picture_buffers_.find(picture.picture_buffer_id());
 362   if (it == assigned_picture_buffers_.end()) {
 363     NOTREACHED() << "Missing picture buffer: " << picture.picture_buffer_id();
 364     NotifyError(media::VideoDecodeAccelerator::PLATFORM_FAILURE);
 365     return;
 366   }
 367   const media::PictureBuffer& pb = it->second;
 368
 369   // Validate picture rectangle from GPU.
 370   if (picture.visible_rect().IsEmpty() ||
 371       !gfx::Rect(pb.size()).Contains(picture.visible_rect())) {
 372     NOTREACHED() << "Invalid picture size from VDA: "
 373                  << picture.visible_rect().ToString() << " should fit in "
 374                  << pb.size().ToString();
 375     NotifyError(media::VideoDecodeAccelerator::PLATFORM_FAILURE);
 376     return;
 377   }
 378
 379   // Create a media::VideoFrame.
 380   uint32_t timestamp = 0;
 381   GetBufferData(picture.bitstream_buffer_id(), &timestamp);
 382   scoped_refptr<media::VideoFrame> frame =
 383       CreateVideoFrame(picture, pb, timestamp);
 384   bool inserted =
 385       picture_buffers_at_display_.insert(std::make_pair(
 386                                              picture.picture_buffer_id(),
 387                                              pb.texture_id())).second;
 388   DCHECK(inserted);
 389
 390   // Create a WebRTC video frame.
 391   webrtc::RefCountImpl<NativeHandleImpl>* handle =
 392       new webrtc::RefCountImpl<NativeHandleImpl>(frame);
 393   webrtc::TextureVideoFrame decoded_image(handle,
 394                                           picture.visible_rect().width(),
 395                                           picture.visible_rect().height(),
 396                                           timestamp,
 397                                           0);
 398
 399   // Invoke decode callback. WebRTC expects no callback after Reset or Release.
 400   {
 401     base::AutoLock auto_lock(lock_);
 402     DCHECK(decode_complete_callback_ != NULL);
 403     if (IsBufferAfterReset(picture.bitstream_buffer_id(),
 404                            reset_bitstream_buffer_id_)) {
 405       decode_complete_callback_->Decoded(decoded_image);
 406     }
 407   }
 408 }
 409
 410 static void ReadPixelsSyncInner(
 411     const scoped_refptr<media::GpuVideoAcceleratorFactories>& factories,
 412     uint32 texture_id,
 413     const gfx::Rect& visible_rect,
 414     const SkBitmap& pixels,
 415     base::WaitableEvent* event) {
 416   factories->ReadPixels(texture_id, visible_rect, pixels);
 417   event->Signal();
 418 }
 419
 420 static void ReadPixelsSync(
 421     const scoped_refptr<media::GpuVideoAcceleratorFactories>& factories,
 422     uint32 texture_id,
 423     const gfx::Rect& visible_rect,
 424     const SkBitmap& pixels) {
 425   base::WaitableEvent event(true, false);
 426   if (!factories->GetTaskRunner()->PostTask(FROM_HERE,
 427                                             base::Bind(&ReadPixelsSyncInner,
 428                                                        factories,
 429                                                        texture_id,
 430                                                        visible_rect,
 431                                                        pixels,
 432                                                        &event)))
 433     return;
 434   event.Wait();
 435 }
 436
 437 scoped_refptr<media::VideoFrame> RTCVideoDecoder::CreateVideoFrame(
 438     const media::Picture& picture,
 439     const media::PictureBuffer& pb,
 440     uint32_t timestamp) {
 441   gfx::Rect visible_rect(picture.visible_rect());
 442   DCHECK(decoder_texture_target_);
 443   // Convert timestamp from 90KHz to ms.
 444   base::TimeDelta timestamp_ms = base::TimeDelta::FromInternalValue(
 445       base::checked_cast<uint64_t>(timestamp) * 1000 / 90);
 446   return media::VideoFrame::WrapNativeTexture(
 447       make_scoped_ptr(new gpu::MailboxHolder(pb.texture_mailbox(),
 448                                              decoder_texture_target_, 0)),
 449       media::BindToCurrentLoop(base::Bind(
 450           &RTCVideoDecoder::ReleaseMailbox, weak_factory_.GetWeakPtr(),
 451           factories_, picture.picture_buffer_id(), pb.texture_id())),
 452       pb.size(), visible_rect, visible_rect.size(), timestamp_ms,
 453       base::Bind(&ReadPixelsSync, factories_, pb.texture_id(), visible_rect),
 454       picture.allow_overlay());
 455 }
 456
 457 void RTCVideoDecoder::NotifyEndOfBitstreamBuffer(int32 id) {
 458   DVLOG(3) << "NotifyEndOfBitstreamBuffer. id=" << id;
 459   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 460
 461   std::map<int32, SHMBuffer*>::iterator it =
 462       bitstream_buffers_in_decoder_.find(id);
 463   if (it == bitstream_buffers_in_decoder_.end()) {
 464     NotifyError(media::VideoDecodeAccelerator::PLATFORM_FAILURE);
 465     NOTREACHED() << "Missing bitstream buffer: " << id;
 466     return;
 467   }
 468
 469   {
 470     base::AutoLock auto_lock(lock_);
 471     PutSHM_Locked(scoped_ptr<SHMBuffer>(it->second));
 472   }
 473   bitstream_buffers_in_decoder_.erase(it);
 474
 475   RequestBufferDecode();
 476 }
 477
 478 void RTCVideoDecoder::NotifyFlushDone() {
 479   DVLOG(3) << "NotifyFlushDone";
 480   NOTREACHED() << "Unexpected flush done notification.";
 481 }
 482
 483 void RTCVideoDecoder::NotifyResetDone() {
 484   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 485   DVLOG(3) << "NotifyResetDone";
 486
 487   if (!vda_)
 488     return;
 489
 490   input_buffer_data_.clear();
 491   {
 492     base::AutoLock auto_lock(lock_);
 493     state_ = INITIALIZED;
 494   }
 495   // Send the pending buffers for decoding.
 496   RequestBufferDecode();
 497 }
 498
 499 void RTCVideoDecoder::NotifyError(media::VideoDecodeAccelerator::Error error) {
 500   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 501   if (!vda_)
 502     return;
 503
 504   LOG(ERROR) << "VDA Error:" << error;
 505   UMA_HISTOGRAM_ENUMERATION("Media.RTCVideoDecoderError",
 506                             error,
 507                             media::VideoDecodeAccelerator::LARGEST_ERROR_ENUM);
 508   DestroyVDA();
 509
 510   base::AutoLock auto_lock(lock_);
 511   state_ = DECODE_ERROR;
 512 }
 513
 514 void RTCVideoDecoder::RequestBufferDecode() {
 515   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 516   if (!vda_)
 517     return;
 518
 519   MovePendingBuffersToDecodeBuffers();
 520
 521   while (CanMoreDecodeWorkBeDone()) {
 522     // Get a buffer and data from the queue.
 523     SHMBuffer* shm_buffer = NULL;
 524     BufferData buffer_data;
 525     {
 526       base::AutoLock auto_lock(lock_);
 527       // Do not request decode if VDA is resetting.
 528       if (decode_buffers_.size() == 0 || state_ == RESETTING)
 529         return;
 530       shm_buffer = decode_buffers_.front().first;
 531       buffer_data = decode_buffers_.front().second;
 532       decode_buffers_.pop_front();
 533       // Drop the buffers before Reset or Release is called.
 534       if (!IsBufferAfterReset(buffer_data.bitstream_buffer_id,
 535                               reset_bitstream_buffer_id_)) {
 536         PutSHM_Locked(scoped_ptr<SHMBuffer>(shm_buffer));
 537         continue;
 538       }
 539     }
 540
 541     // Create a BitstreamBuffer and send to VDA to decode.
 542     media::BitstreamBuffer bitstream_buffer(buffer_data.bitstream_buffer_id,
 543                                             shm_buffer->shm->handle(),
 544                                             buffer_data.size);
 545     bool inserted = bitstream_buffers_in_decoder_
 546         .insert(std::make_pair(bitstream_buffer.id(), shm_buffer)).second;
 547     DCHECK(inserted);
 548     RecordBufferData(buffer_data);
 549     vda_->Decode(bitstream_buffer);
 550   }
 551 }
 552
 553 bool RTCVideoDecoder::CanMoreDecodeWorkBeDone() {
 554   return bitstream_buffers_in_decoder_.size() < kMaxInFlightDecodes;
 555 }
 556
 557 bool RTCVideoDecoder::IsBufferAfterReset(int32 id_buffer, int32 id_reset) {
 558   if (id_reset == ID_INVALID)
 559     return true;
 560   int32 diff = id_buffer - id_reset;
 561   if (diff <= 0)
 562     diff += ID_LAST + 1;
 563   return diff < ID_HALF;
 564 }
 565
 566 bool RTCVideoDecoder::IsFirstBufferAfterReset(int32 id_buffer, int32 id_reset) {
 567   if (id_reset == ID_INVALID)
 568     return id_buffer == 0;
 569   return id_buffer == ((id_reset + 1) & ID_LAST);
 570 }
 571
 572 void RTCVideoDecoder::SaveToDecodeBuffers_Locked(
 573     const webrtc::EncodedImage& input_image,
 574     scoped_ptr<SHMBuffer> shm_buffer,
 575     const BufferData& buffer_data) {
 576   memcpy(shm_buffer->shm->memory(), input_image._buffer, input_image._length);
 577   std::pair<SHMBuffer*, BufferData> buffer_pair =
 578       std::make_pair(shm_buffer.release(), buffer_data);
 579
 580   // Store the buffer and the metadata to the queue.
 581   decode_buffers_.push_back(buffer_pair);
 582 }
 583
 584 bool RTCVideoDecoder::SaveToPendingBuffers_Locked(
 585     const webrtc::EncodedImage& input_image,
 586     const BufferData& buffer_data) {
 587   DVLOG(2) << "SaveToPendingBuffers_Locked"
 588            << ". pending_buffers size=" << pending_buffers_.size()
 589            << ". decode_buffers_ size=" << decode_buffers_.size()
 590            << ". available_shm size=" << available_shm_segments_.size();
 591   // Queued too many buffers. Something goes wrong.
 592   if (pending_buffers_.size() >= kMaxNumOfPendingBuffers) {
 593     LOG(WARNING) << "Too many pending buffers!";
 594     return false;
 595   }
 596
 597   // Clone the input image and save it to the queue.
 598   uint8_t* buffer = new uint8_t[input_image._length];
 599   // TODO(wuchengli): avoid memcpy. Extend webrtc::VideoDecoder::Decode()
 600   // interface to take a non-const ptr to the frame and add a method to the
 601   // frame that will swap buffers with another.
 602   memcpy(buffer, input_image._buffer, input_image._length);
 603   webrtc::EncodedImage encoded_image(
 604       buffer, input_image._length, input_image._length);
 605   std::pair<webrtc::EncodedImage, BufferData> buffer_pair =
 606       std::make_pair(encoded_image, buffer_data);
 607
 608   pending_buffers_.push_back(buffer_pair);
 609   return true;
 610 }
 611
 612 void RTCVideoDecoder::MovePendingBuffersToDecodeBuffers() {
 613   base::AutoLock auto_lock(lock_);
 614   while (pending_buffers_.size() > 0) {
 615     // Get a pending buffer from the queue.
 616     const webrtc::EncodedImage& input_image = pending_buffers_.front().first;
 617     const BufferData& buffer_data = pending_buffers_.front().second;
 618
 619     // Drop the frame if it comes before Reset or Release.
 620     if (!IsBufferAfterReset(buffer_data.bitstream_buffer_id,
 621                             reset_bitstream_buffer_id_)) {
 622       delete[] input_image._buffer;
 623       pending_buffers_.pop_front();
 624       continue;
 625     }
 626     // Get shared memory and save it to decode buffers.
 627     scoped_ptr<SHMBuffer> shm_buffer = GetSHM_Locked(input_image._length);
 628     if (!shm_buffer)
 629       return;
 630     SaveToDecodeBuffers_Locked(input_image, shm_buffer.Pass(), buffer_data);
 631     delete[] input_image._buffer;
 632     pending_buffers_.pop_front();
 633   }
 634 }
 635
 636 void RTCVideoDecoder::ResetInternal() {
 637   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 638   DVLOG(2) << "ResetInternal";
 639   if (vda_)
 640     vda_->Reset();
 641 }
 642
 643 // static
 644 void RTCVideoDecoder::ReleaseMailbox(
 645     base::WeakPtr<RTCVideoDecoder> decoder,
 646     const scoped_refptr<media::GpuVideoAcceleratorFactories>& factories,
 647     int64 picture_buffer_id,
 648     uint32 texture_id,
 649     uint32 release_sync_point) {
 650   DCHECK(factories->GetTaskRunner()->BelongsToCurrentThread());
 651   factories->WaitSyncPoint(release_sync_point);
 652
 653   if (decoder) {
 654     decoder->ReusePictureBuffer(picture_buffer_id);
 655     return;
 656   }
 657   // It's the last chance to delete the texture after display,
 658   // because RTCVideoDecoder was destructed.
 659   factories->DeleteTexture(texture_id);
 660 }
 661
 662 void RTCVideoDecoder::ReusePictureBuffer(int64 picture_buffer_id) {
 663   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 664   DVLOG(3) << "ReusePictureBuffer. id=" << picture_buffer_id;
 665
 666   DCHECK(!picture_buffers_at_display_.empty());
 667   PictureBufferTextureMap::iterator display_iterator =
 668       picture_buffers_at_display_.find(picture_buffer_id);
 669   uint32 texture_id = display_iterator->second;
 670   DCHECK(display_iterator != picture_buffers_at_display_.end());
 671   picture_buffers_at_display_.erase(display_iterator);
 672
 673   if (!assigned_picture_buffers_.count(picture_buffer_id)) {
 674     // This picture was dismissed while in display, so we postponed deletion.
 675     factories_->DeleteTexture(texture_id);
 676     return;
 677   }
 678
 679   // DestroyVDA() might already have been called.
 680   if (vda_)
 681     vda_->ReusePictureBuffer(picture_buffer_id);
 682 }
 683
 684 void RTCVideoDecoder::CreateVDA(media::VideoCodecProfile profile,
 685                                 base::WaitableEvent* waiter) {
 686   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 687   vda_ = factories_->CreateVideoDecodeAccelerator();
 688   if (vda_ && !vda_->Initialize(profile, this))
 689     vda_.release()->Destroy();
 690   waiter->Signal();
 691 }
 692
 693 void RTCVideoDecoder::DestroyTextures() {
 694   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 695
 696   // Not destroying PictureBuffers in |picture_buffers_at_display_| yet, since
 697   // their textures may still be in use by the user of this RTCVideoDecoder.
 698   for (PictureBufferTextureMap::iterator it =
 699            picture_buffers_at_display_.begin();
 700        it != picture_buffers_at_display_.end();
 701        ++it) {
 702     assigned_picture_buffers_.erase(it->first);
 703   }
 704
 705   for (std::map<int32, media::PictureBuffer>::iterator it =
 706            assigned_picture_buffers_.begin();
 707        it != assigned_picture_buffers_.end();
 708        ++it) {
 709     factories_->DeleteTexture(it->second.texture_id());
 710   }
 711   assigned_picture_buffers_.clear();
 712 }
 713
 714 void RTCVideoDecoder::DestroyVDA() {
 715   DVLOG(2) << "DestroyVDA";
 716   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 717   if (vda_)
 718     vda_.release()->Destroy();
 719   DestroyTextures();
 720   base::AutoLock auto_lock(lock_);
 721   state_ = UNINITIALIZED;
 722 }
 723
 724 scoped_ptr<RTCVideoDecoder::SHMBuffer> RTCVideoDecoder::GetSHM_Locked(
 725     size_t min_size) {
 726   // Reuse a SHM if possible.
 727   SHMBuffer* ret = NULL;
 728   if (!available_shm_segments_.empty() &&
 729       available_shm_segments_.back()->size >= min_size) {
 730     ret = available_shm_segments_.back();
 731     available_shm_segments_.pop_back();
 732   }
 733   // Post to vda thread to create shared memory if SHM cannot be reused or the
 734   // queue is almost empty.
 735   if (num_shm_buffers_ < kMaxNumSharedMemorySegments &&
 736       (ret == NULL || available_shm_segments_.size() <= 1)) {
 737     factories_->GetTaskRunner()->PostTask(
 738         FROM_HERE,
 739         base::Bind(&RTCVideoDecoder::CreateSHM,
 740                    weak_factory_.GetWeakPtr(),
 741                    1,
 742                    min_size));
 743   }
 744   return scoped_ptr<SHMBuffer>(ret);
 745 }
 746
 747 void RTCVideoDecoder::PutSHM_Locked(scoped_ptr<SHMBuffer> shm_buffer) {
 748   available_shm_segments_.push_back(shm_buffer.release());
 749 }
 750
 751 void RTCVideoDecoder::CreateSHM(int number, size_t min_size) {
 752   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 753   DVLOG(2) << "CreateSHM. size=" << min_size;
 754   int number_to_allocate;
 755   {
 756     base::AutoLock auto_lock(lock_);
 757     number_to_allocate =
 758         std::min(kMaxNumSharedMemorySegments - num_shm_buffers_, number);
 759   }
 760   size_t size_to_allocate = std::max(min_size, kSharedMemorySegmentBytes);
 761   for (int i = 0; i < number_to_allocate; i++) {
 762     scoped_ptr<base::SharedMemory> shm =
 763         factories_->CreateSharedMemory(size_to_allocate);
 764     if (shm) {
 765       base::AutoLock auto_lock(lock_);
 766       num_shm_buffers_++;
 767       PutSHM_Locked(
 768           scoped_ptr<SHMBuffer>(new SHMBuffer(shm.Pass(), size_to_allocate)));
 769     }
 770   }
 771   // Kick off the decoding.
 772   RequestBufferDecode();
 773 }
 774
 775 void RTCVideoDecoder::RecordBufferData(const BufferData& buffer_data) {
 776   input_buffer_data_.push_front(buffer_data);
 777   // Why this value?  Because why not.  avformat.h:MAX_REORDER_DELAY is 16, but
 778   // that's too small for some pathological B-frame test videos.  The cost of
 779   // using too-high a value is low (192 bits per extra slot).
 780   static const size_t kMaxInputBufferDataSize = 128;
 781   // Pop from the back of the list, because that's the oldest and least likely
 782   // to be useful in the future data.
 783   if (input_buffer_data_.size() > kMaxInputBufferDataSize)
 784     input_buffer_data_.pop_back();
 785 }
 786
 787 void RTCVideoDecoder::GetBufferData(int32 bitstream_buffer_id,
 788                                     uint32_t* timestamp) {
 789   for (std::list<BufferData>::iterator it = input_buffer_data_.begin();
 790        it != input_buffer_data_.end();
 791        ++it) {
 792     if (it->bitstream_buffer_id != bitstream_buffer_id)
 793       continue;
 794     *timestamp = it->timestamp;
 795     return;
 796   }
 797   NOTREACHED() << "Missing bitstream buffer id: " << bitstream_buffer_id;
 798 }
 799
 800 int32_t RTCVideoDecoder::RecordInitDecodeUMA(int32_t status) {
 801   // Logging boolean is enough to know if HW decoding has been used. Also,
 802   // InitDecode is less likely to return an error so enum is not used here.
 803   bool sample = (status == WEBRTC_VIDEO_CODEC_OK) ? true : false;
 804   UMA_HISTOGRAM_BOOLEAN("Media.RTCVideoDecoderInitDecodeSuccess", sample);
 805   return status;
 806 }
 807
 808 void RTCVideoDecoder::DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent()
 809     const {
 810   DCHECK(factories_->GetTaskRunner()->BelongsToCurrentThread());
 811 }
 812
 813 }  // namespace content