media/filters/vpx_video_decoder.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/filters/vpx_video_decoder.h"

#include <stddef.h>
#include <stdint.h>

#include <algorithm>
#include <string>
#include <vector>

#include "base/bind.h"
#include "base/callback_helpers.h"
#include "base/command_line.h"
#include "base/lazy_instance.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/single_thread_task_runner.h"
#include "base/stl_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/sys_byteorder.h"
#include "base/sys_info.h"
#include "base/threading/thread.h"
#include "base/trace_event/memory_allocator_dump.h"
#include "base/trace_event/memory_dump_manager.h"
#include "base/trace_event/memory_dump_provider.h"
#include "base/trace_event/process_memory_dump.h"
#include "base/trace_event/trace_event.h"
#include "media/base/bind_to_current_loop.h"
#include "media/base/decoder_buffer.h"
#include "media/base/media_switches.h"

// Include libvpx header files.
// VPX_CODEC_DISABLE_COMPAT excludes parts of the libvpx API that provide
// backwards compatibility for legacy applications using the library.
#define VPX_CODEC_DISABLE_COMPAT 1
extern "C" {
#include "third_party/libvpx/source/libvpx/vpx/vp8dx.h"
#include "third_party/libvpx/source/libvpx/vpx/vpx_decoder.h"
#include "third_party/libvpx/source/libvpx/vpx/vpx_frame_buffer.h"
}

#include "third_party/libyuv/include/libyuv/convert.h"

namespace media {

// High resolution VP9 decodes can block the main task runner for too long,
// preventing demuxing, audio decoding, and other control activities.  In those
// cases share a thread per process for higher resolution decodes.
//
// All calls into this class must be done on the per-process media thread.
class VpxOffloadThread {
 public:
  VpxOffloadThread() : offload_thread_("VpxOffloadThread") {}
  ~VpxOffloadThread() {}

  scoped_refptr<base::SingleThreadTaskRunner> RequestOffloadThread() {
    DCHECK(thread_checker_.CalledOnValidThread());
    ++offload_thread_users_;
    if (!offload_thread_.IsRunning())
      offload_thread_.Start();

    return offload_thread_.task_runner();
  }

  void WaitForOutstandingTasks() {
    DCHECK(thread_checker_.CalledOnValidThread());
    DCHECK(offload_thread_users_);
    DCHECK(offload_thread_.IsRunning());
    base::WaitableEvent waiter(base::WaitableEvent::ResetPolicy::AUTOMATIC,
                               base::WaitableEvent::InitialState::NOT_SIGNALED);
    offload_thread_.task_runner()->PostTask(
        FROM_HERE,
        base::Bind(&base::WaitableEvent::Signal, base::Unretained(&waiter)));
    waiter.Wait();
  }

  void WaitForOutstandingTasksAndReleaseOffloadThread() {
    DCHECK(thread_checker_.CalledOnValidThread());
    DCHECK(offload_thread_users_);
    DCHECK(offload_thread_.IsRunning());
    WaitForOutstandingTasks();
    if (!--offload_thread_users_) {
      // Don't shut down the thread immediately in case we're in the middle of
      // a configuration change.
      base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
          FROM_HERE, base::Bind(&VpxOffloadThread::ShutdownOffloadThread,
                                base::Unretained(this)),
          base::TimeDelta::FromSeconds(5));
    }
  }

 private:
  void ShutdownOffloadThread() {
    DCHECK(thread_checker_.CalledOnValidThread());
    if (!offload_thread_users_)
      offload_thread_.Stop();
  }

  int offload_thread_users_ = 0;
  base::Thread offload_thread_;
  base::ThreadChecker thread_checker_;

  DISALLOW_COPY_AND_ASSIGN(VpxOffloadThread);
};

static base::LazyInstance<VpxOffloadThread>::Leaky g_vpx_offload_thread =
    LAZY_INSTANCE_INITIALIZER;

// Always try to use three threads for video decoding.  There is little reason
// not to since current day CPUs tend to be multi-core and we measured
// performance benefits on older machines such as P4s with hyperthreading.
static const int kDecodeThreads = 2;
static const int kMaxDecodeThreads = 16;

// Returns the number of threads.
static int GetThreadCount(const VideoDecoderConfig& config) {
  // Refer to http://crbug.com/93932 for tsan suppressions on decoding.
  int decode_threads = kDecodeThreads;

  const base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
  std::string threads(cmd_line->GetSwitchValueASCII(switches::kVideoThreads));
  if (threads.empty() || !base::StringToInt(threads, &decode_threads)) {
    if (config.codec() == kCodecVP9) {
      // For VP9 decode when using the default thread count, increase the number
      // of decode threads to equal the maximum number of tiles possible for
      // higher resolution streams.
      if (config.coded_size().width() >= 2048)
        decode_threads = 8;
      else if (config.coded_size().width() >= 1024)
        decode_threads = 4;
    }

    decode_threads = std::min(decode_threads,
                              base::SysInfo::NumberOfProcessors());
    return decode_threads;
  }

  decode_threads = std::max(decode_threads, 0);
  decode_threads = std::min(decode_threads, kMaxDecodeThreads);
  return decode_threads;
}

static vpx_codec_ctx* InitializeVpxContext(vpx_codec_ctx* context,
                                           const VideoDecoderConfig& config) {
  context = new vpx_codec_ctx();
  vpx_codec_dec_cfg_t vpx_config = {0};
  vpx_config.w = config.coded_size().width();
  vpx_config.h = config.coded_size().height();
  vpx_config.threads = GetThreadCount(config);

  vpx_codec_err_t status = vpx_codec_dec_init(
      context,
      config.codec() == kCodecVP9 ? vpx_codec_vp9_dx() : vpx_codec_vp8_dx(),
      &vpx_config, 0 /* flags */);
  if (status == VPX_CODEC_OK)
    return context;

  DLOG(ERROR) << "vpx_codec_dec_init() failed: " << vpx_codec_error(context);
  delete context;
  return nullptr;
}

// MemoryPool is a pool of simple CPU memory, allocated by hand and used by both
// VP9 and any data consumers. This class needs to be ref-counted to hold on to
// allocated memory via the memory-release callback of CreateFrameCallback().
class VpxVideoDecoder::MemoryPool
    : public base::RefCountedThreadSafe<VpxVideoDecoder::MemoryPool>,
      public base::trace_event::MemoryDumpProvider {
 public:
  MemoryPool();

  // Callback that will be called by libvpx when it needs a frame buffer.
  // Parameters:
  // |user_priv|  Private data passed to libvpx (pointer to memory pool).
  // |min_size|   Minimum size needed by libvpx to decompress the next frame.
  // |fb|         Pointer to the frame buffer to update.
  // Returns 0 on success. Returns < 0 on failure.
  static int32_t GetVP9FrameBuffer(void* user_priv,
                                   size_t min_size,
                                   vpx_codec_frame_buffer* fb);

  // Callback that will be called by libvpx when the frame buffer is no longer
  // being used by libvpx. Can be called with NULL user data when decode stops
  // because of an invalid bitstream.
  // Parameters:
  // |user_priv|  Private data passed to libvpx (pointer to memory pool).
  // |fb|         Pointer to the frame buffer that's being released.
  // Returns 0 on success. Returns < 0 on failure.
  static int32_t ReleaseVP9FrameBuffer(void* user_priv,
                                       vpx_codec_frame_buffer* fb);

  // Generates a "no_longer_needed" closure that holds a reference to this pool.
  base::Closure CreateFrameCallback(void* fb_priv_data);

  // base::MemoryDumpProvider.
  bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
                    base::trace_event::ProcessMemoryDump* pmd) override;

 private:
  friend class base::RefCountedThreadSafe<VpxVideoDecoder::MemoryPool>;
  ~MemoryPool() override;

  // Reference counted frame buffers used for VP9 decoding. Reference counting
  // is done manually because both chromium and libvpx has to release this
  // before a buffer can be re-used.
  struct VP9FrameBuffer {
    VP9FrameBuffer() : ref_cnt(0) {}
    std::vector<uint8_t> data;
    uint32_t ref_cnt;
  };

  // Gets the next available frame buffer for use by libvpx.
  VP9FrameBuffer* GetFreeFrameBuffer(size_t min_size);

  // Method that gets called when a VideoFrame that references this pool gets
  // destroyed.
  void OnVideoFrameDestroyed(VP9FrameBuffer* frame_buffer);

  // Frame buffers to be used by libvpx for VP9 Decoding.
  std::vector<VP9FrameBuffer*> frame_buffers_;

  DISALLOW_COPY_AND_ASSIGN(MemoryPool);
};

VpxVideoDecoder::MemoryPool::MemoryPool() {
  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
      this, "VpxVideoDecoder", base::ThreadTaskRunnerHandle::Get());
}

VpxVideoDecoder::MemoryPool::~MemoryPool() {
  STLDeleteElements(&frame_buffers_);
  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
      this);
}

VpxVideoDecoder::MemoryPool::VP9FrameBuffer*
VpxVideoDecoder::MemoryPool::GetFreeFrameBuffer(size_t min_size) {
  // Check if a free frame buffer exists.
  size_t i = 0;
  for (; i < frame_buffers_.size(); ++i) {
    if (frame_buffers_[i]->ref_cnt == 0)
      break;
  }

  if (i == frame_buffers_.size()) {
    // Create a new frame buffer.
    frame_buffers_.push_back(new VP9FrameBuffer());
  }

  // Resize the frame buffer if necessary.
  if (frame_buffers_[i]->data.size() < min_size)
    frame_buffers_[i]->data.resize(min_size);
  return frame_buffers_[i];
}

int32_t VpxVideoDecoder::MemoryPool::GetVP9FrameBuffer(
    void* user_priv,
    size_t min_size,
    vpx_codec_frame_buffer* fb) {
  DCHECK(user_priv);
  DCHECK(fb);

  VpxVideoDecoder::MemoryPool* memory_pool =
      static_cast<VpxVideoDecoder::MemoryPool*>(user_priv);

  VP9FrameBuffer* fb_to_use = memory_pool->GetFreeFrameBuffer(min_size);
  if (fb_to_use == NULL)
    return -1;

  fb->data = &fb_to_use->data[0];
  fb->size = fb_to_use->data.size();
  ++fb_to_use->ref_cnt;

  // Set the frame buffer's private data to point at the external frame buffer.
  fb->priv = static_cast<void*>(fb_to_use);
  return 0;
}

int32_t VpxVideoDecoder::MemoryPool::ReleaseVP9FrameBuffer(
    void* user_priv,
    vpx_codec_frame_buffer* fb) {
  DCHECK(user_priv);
  DCHECK(fb);

  if (!fb->priv)
    return -1;

  VP9FrameBuffer* frame_buffer = static_cast<VP9FrameBuffer*>(fb->priv);
  --frame_buffer->ref_cnt;
  return 0;
}

base::Closure VpxVideoDecoder::MemoryPool::CreateFrameCallback(
    void* fb_priv_data) {
  VP9FrameBuffer* frame_buffer = static_cast<VP9FrameBuffer*>(fb_priv_data);
  ++frame_buffer->ref_cnt;
  return BindToCurrentLoop(
      base::Bind(&MemoryPool::OnVideoFrameDestroyed, this, frame_buffer));
}

bool VpxVideoDecoder::MemoryPool::OnMemoryDump(
    const base::trace_event::MemoryDumpArgs& args,
    base::trace_event::ProcessMemoryDump* pmd) {
  base::trace_event::MemoryAllocatorDump* memory_dump =
      pmd->CreateAllocatorDump("media/vpx/memory_pool");
  base::trace_event::MemoryAllocatorDump* used_memory_dump =
      pmd->CreateAllocatorDump("media/vpx/memory_pool/used");

  pmd->AddSuballocation(memory_dump->guid(),
                        base::trace_event::MemoryDumpManager::GetInstance()
                            ->system_allocator_pool_name());
  size_t bytes_used = 0;
  size_t bytes_reserved = 0;
  for (const VP9FrameBuffer* frame_buffer : frame_buffers_) {
    if (frame_buffer->ref_cnt)
      bytes_used += frame_buffer->data.size();
    bytes_reserved += frame_buffer->data.size();
  }

  memory_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                         base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                         bytes_reserved);
  used_memory_dump->AddScalar(
      base::trace_event::MemoryAllocatorDump::kNameSize,
      base::trace_event::MemoryAllocatorDump::kUnitsBytes, bytes_used);

  return true;
}

void VpxVideoDecoder::MemoryPool::OnVideoFrameDestroyed(
    VP9FrameBuffer* frame_buffer) {
  --frame_buffer->ref_cnt;
}

VpxVideoDecoder::VpxVideoDecoder()
    : state_(kUninitialized), vpx_codec_(nullptr), vpx_codec_alpha_(nullptr) {
  thread_checker_.DetachFromThread();
}

VpxVideoDecoder::~VpxVideoDecoder() {
  DCHECK(thread_checker_.CalledOnValidThread());
  CloseDecoder();
  // Ensure CloseDecoder() released the offload thread.
  DCHECK(!offload_task_runner_);
}

std::string VpxVideoDecoder::GetDisplayName() const {
  return "VpxVideoDecoder";
}

void VpxVideoDecoder::Initialize(const VideoDecoderConfig& config,
                                 bool /* low_delay */,
                                 CdmContext* /* cdm_context */,
                                 const InitCB& init_cb,
                                 const OutputCB& output_cb) {
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK(config.IsValidConfig());

  InitCB bound_init_cb = BindToCurrentLoop(init_cb);

  if (config.is_encrypted() || !ConfigureDecoder(config)) {
    bound_init_cb.Run(false);
    return;
  }

  // Success!
  config_ = config;
  state_ = kNormal;
  output_cb_ = offload_task_runner_ ? BindToCurrentLoop(output_cb) : output_cb;
  bound_init_cb.Run(true);
}

void VpxVideoDecoder::DecodeBuffer(const scoped_refptr<DecoderBuffer>& buffer,
                                   const DecodeCB& bound_decode_cb) {
  DCHECK_NE(state_, kUninitialized)
      << "Called Decode() before successful Initialize()";

  if (state_ == kError) {
    bound_decode_cb.Run(DecodeStatus::DECODE_ERROR);
    return;
  }

  if (state_ == kDecodeFinished) {
    bound_decode_cb.Run(DecodeStatus::OK);
    return;
  }

  if (state_ == kNormal && buffer->end_of_stream()) {
    state_ = kDecodeFinished;
    bound_decode_cb.Run(DecodeStatus::OK);
    return;
  }

  scoped_refptr<VideoFrame> video_frame;
  if (!VpxDecode(buffer, &video_frame)) {
    state_ = kError;
    bound_decode_cb.Run(DecodeStatus::DECODE_ERROR);
    return;
  }

  // We might get a successful VpxDecode but not a frame if only a partial
  // decode happened.
  if (video_frame) {
    // Safe to call |output_cb_| here even if we're on the offload thread since
    // it is only set once during Initialize() and never changed.
    output_cb_.Run(video_frame);
  }

  // VideoDecoderShim expects |decode_cb| call after |output_cb_|.
  bound_decode_cb.Run(DecodeStatus::OK);
}

void VpxVideoDecoder::Decode(const scoped_refptr<DecoderBuffer>& buffer,
                             const DecodeCB& decode_cb) {
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK(buffer.get());
  DCHECK(!decode_cb.is_null());

  DecodeCB bound_decode_cb = BindToCurrentLoop(decode_cb);

  if (offload_task_runner_) {
    offload_task_runner_->PostTask(
        FROM_HERE, base::Bind(&VpxVideoDecoder::DecodeBuffer,
                              base::Unretained(this), buffer, bound_decode_cb));
  } else {
    DecodeBuffer(buffer, bound_decode_cb);
  }
}

void VpxVideoDecoder::Reset(const base::Closure& closure) {
  DCHECK(thread_checker_.CalledOnValidThread());
  if (offload_task_runner_)
    g_vpx_offload_thread.Pointer()->WaitForOutstandingTasks();

  state_ = kNormal;
  // PostTask() to avoid calling |closure| inmediately.
  base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE, closure);
}

bool VpxVideoDecoder::ConfigureDecoder(const VideoDecoderConfig& config) {
  if (config.codec() != kCodecVP8 && config.codec() != kCodecVP9)
    return false;

  // These are the combinations of codec-pixel format supported in principle.
  // Note that VP9 does not support Alpha in the current implementation.
  DCHECK(
      (config.codec() == kCodecVP8 && config.format() == PIXEL_FORMAT_YV12) ||
      (config.codec() == kCodecVP8 && config.format() == PIXEL_FORMAT_YV12A) ||
      (config.codec() == kCodecVP9 && config.format() == PIXEL_FORMAT_YV12) ||
      (config.codec() == kCodecVP9 && config.format() == PIXEL_FORMAT_YV24));

#if !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
  // When FFmpegVideoDecoder is available it handles VP8 that doesn't have
  // alpha, and VpxVideoDecoder will handle VP8 with alpha.
  if (config.codec() == kCodecVP8 && config.format() != PIXEL_FORMAT_YV12A)
    return false;
#endif

  CloseDecoder();

  vpx_codec_ = InitializeVpxContext(vpx_codec_, config);
  if (!vpx_codec_)
    return false;

  // Configure VP9 to decode on our buffers to skip a data copy on decoding.
  if (config.codec() == kCodecVP9) {
    DCHECK_NE(PIXEL_FORMAT_YV12A, config.format());
    DCHECK(vpx_codec_get_caps(vpx_codec_->iface) &
           VPX_CODEC_CAP_EXTERNAL_FRAME_BUFFER);

    // Move high resolution vp9 decodes off of the main media thread (otherwise
    // decode may block audio decoding, demuxing, and other control activities).
    if (config.coded_size().width() >= 1024) {
      offload_task_runner_ =
          g_vpx_offload_thread.Pointer()->RequestOffloadThread();
    }

    memory_pool_ = new MemoryPool();
    if (vpx_codec_set_frame_buffer_functions(vpx_codec_,
                                             &MemoryPool::GetVP9FrameBuffer,
                                             &MemoryPool::ReleaseVP9FrameBuffer,
                                             memory_pool_.get())) {
      DLOG(ERROR) << "Failed to configure external buffers. "
                  << vpx_codec_error(vpx_codec_);
      return false;
    }
  }

  if (config.format() != PIXEL_FORMAT_YV12A)
    return true;

  vpx_codec_alpha_ = InitializeVpxContext(vpx_codec_alpha_, config);
  return !!vpx_codec_alpha_;
}

void VpxVideoDecoder::CloseDecoder() {
  if (offload_task_runner_) {
    g_vpx_offload_thread.Pointer()
        ->WaitForOutstandingTasksAndReleaseOffloadThread();
    offload_task_runner_ = nullptr;
  }

  if (vpx_codec_) {
    vpx_codec_destroy(vpx_codec_);
    delete vpx_codec_;
    vpx_codec_ = nullptr;
    memory_pool_ = nullptr;
  }
  if (vpx_codec_alpha_) {
    vpx_codec_destroy(vpx_codec_alpha_);
    delete vpx_codec_alpha_;
    vpx_codec_alpha_ = nullptr;
  }
}

bool VpxVideoDecoder::VpxDecode(const scoped_refptr<DecoderBuffer>& buffer,
                                scoped_refptr<VideoFrame>* video_frame) {
  DCHECK(video_frame);
  DCHECK(!buffer->end_of_stream());

  int64_t timestamp = buffer->timestamp().InMicroseconds();
  void* user_priv = reinterpret_cast<void*>(&timestamp);
  {
    TRACE_EVENT1("media", "vpx_codec_decode", "timestamp", timestamp);
    vpx_codec_err_t status =
        vpx_codec_decode(vpx_codec_, buffer->data(), buffer->data_size(),
                         user_priv, 0 /* deadline */);
    if (status != VPX_CODEC_OK) {
      DLOG(ERROR) << "vpx_codec_decode() error: "
                  << vpx_codec_err_to_string(status);
      return false;
    }
  }

  // Gets pointer to decoded data.
  vpx_codec_iter_t iter = NULL;
  const vpx_image_t* vpx_image = vpx_codec_get_frame(vpx_codec_, &iter);
  if (!vpx_image) {
    *video_frame = nullptr;
    return true;
  }

  if (vpx_image->user_priv != user_priv) {
    DLOG(ERROR) << "Invalid output timestamp.";
    return false;
  }

  if (!CopyVpxImageToVideoFrame(vpx_image, video_frame))
    return false;

  (*video_frame)->set_timestamp(base::TimeDelta::FromMicroseconds(timestamp));

  // Default to the color space from the config, but if the bistream specifies
  // one, prefer that instead.
  ColorSpace color_space = config_.color_space();
  if (vpx_image->cs == VPX_CS_BT_709)
    color_space = COLOR_SPACE_HD_REC709;
  else if (vpx_image->cs == VPX_CS_BT_601)
    color_space = COLOR_SPACE_SD_REC601;
  (*video_frame)
      ->metadata()
      ->SetInteger(VideoFrameMetadata::COLOR_SPACE, color_space);

  if (!vpx_codec_alpha_)
    return true;

  if (buffer->side_data_size() < 8) {
    // TODO(mcasas): Is this a warning or an error?
    DLOG(WARNING) << "Making Alpha channel opaque due to missing input";
    const uint32_t kAlphaOpaqueValue = 255;
    libyuv::SetPlane((*video_frame)->visible_data(VideoFrame::kAPlane),
                     (*video_frame)->stride(VideoFrame::kAPlane),
                     (*video_frame)->visible_rect().width(),
                     (*video_frame)->visible_rect().height(),
                     kAlphaOpaqueValue);
    return true;
  }

  // First 8 bytes of side data is |side_data_id| in big endian.
  const uint64_t side_data_id = base::NetToHost64(
      *(reinterpret_cast<const uint64_t*>(buffer->side_data())));
  if (side_data_id != 1)
    return true;

  // Try and decode buffer->side_data() minus the first 8 bytes as a full frame.
  int64_t timestamp_alpha = buffer->timestamp().InMicroseconds();
  void* user_priv_alpha = reinterpret_cast<void*>(&timestamp_alpha);
  {
    TRACE_EVENT1("media", "vpx_codec_decode_alpha", "timestamp_alpha",
                 timestamp_alpha);
    vpx_codec_err_t status = vpx_codec_decode(
        vpx_codec_alpha_, buffer->side_data() + 8, buffer->side_data_size() - 8,
        user_priv_alpha, 0 /* deadline */);
    if (status != VPX_CODEC_OK) {
      DLOG(ERROR) << "vpx_codec_decode() failed for the alpha: "
                  << vpx_codec_error(vpx_codec_);
      return false;
    }
  }

  vpx_codec_iter_t iter_alpha = NULL;
  const vpx_image_t* vpx_image_alpha =
      vpx_codec_get_frame(vpx_codec_alpha_, &iter_alpha);
  if (!vpx_image_alpha) {
    *video_frame = nullptr;
    return true;
  }

  if (vpx_image_alpha->user_priv != user_priv_alpha) {
    DLOG(ERROR) << "Invalid output timestamp on alpha.";
    return false;
  }

  if (vpx_image_alpha->d_h != vpx_image->d_h ||
      vpx_image_alpha->d_w != vpx_image->d_w) {
    DLOG(ERROR) << "The alpha plane dimensions are not the same as the "
                   "image dimensions.";
    return false;
  }

  libyuv::CopyPlane(vpx_image_alpha->planes[VPX_PLANE_Y],
                    vpx_image_alpha->stride[VPX_PLANE_Y],
                    (*video_frame)->visible_data(VideoFrame::kAPlane),
                    (*video_frame)->stride(VideoFrame::kAPlane),
                    (*video_frame)->visible_rect().width(),
                    (*video_frame)->visible_rect().height());
  return true;
}

bool VpxVideoDecoder::CopyVpxImageToVideoFrame(
    const struct vpx_image* vpx_image,
    scoped_refptr<VideoFrame>* video_frame) {
  DCHECK(vpx_image);

  VideoPixelFormat codec_format;
  switch (vpx_image->fmt) {
    case VPX_IMG_FMT_I420:
      codec_format = vpx_codec_alpha_ ? PIXEL_FORMAT_YV12A : PIXEL_FORMAT_YV12;
      break;

    case VPX_IMG_FMT_I444:
      codec_format = PIXEL_FORMAT_YV24;
      break;

    default:
      DLOG(ERROR) << "Unsupported pixel format: " << vpx_image->fmt;
      return false;
  }

  // The mixed |w|/|d_h| in |coded_size| is intentional. Setting the correct
  // coded width is necessary to allow coalesced memory access, which may avoid
  // frame copies. Setting the correct coded height however does not have any
  // benefit, and only risk copying too much data.
  const gfx::Size coded_size(vpx_image->w, vpx_image->d_h);
  const gfx::Size visible_size(vpx_image->d_w, vpx_image->d_h);

  if (memory_pool_.get()) {
    DCHECK_EQ(kCodecVP9, config_.codec());
    DCHECK(!vpx_codec_alpha_) << "Uh-oh, VP9 and Alpha shouldn't coexist.";
    *video_frame = VideoFrame::WrapExternalYuvData(
        codec_format,
        coded_size, gfx::Rect(visible_size), config_.natural_size(),
        vpx_image->stride[VPX_PLANE_Y],
        vpx_image->stride[VPX_PLANE_U],
        vpx_image->stride[VPX_PLANE_V],
        vpx_image->planes[VPX_PLANE_Y],
        vpx_image->planes[VPX_PLANE_U],
        vpx_image->planes[VPX_PLANE_V],
        kNoTimestamp());
    if (!(*video_frame))
      return false;

    video_frame->get()->AddDestructionObserver(
        memory_pool_->CreateFrameCallback(vpx_image->fb_priv));
    return true;
  }

  DCHECK(codec_format == PIXEL_FORMAT_YV12 ||
         codec_format == PIXEL_FORMAT_YV12A);

  *video_frame = frame_pool_.CreateFrame(
      codec_format, visible_size, gfx::Rect(visible_size),
      config_.natural_size(), kNoTimestamp());
  if (!(*video_frame))
    return false;

  libyuv::I420Copy(
      vpx_image->planes[VPX_PLANE_Y], vpx_image->stride[VPX_PLANE_Y],
      vpx_image->planes[VPX_PLANE_U], vpx_image->stride[VPX_PLANE_U],
      vpx_image->planes[VPX_PLANE_V], vpx_image->stride[VPX_PLANE_V],
      (*video_frame)->visible_data(VideoFrame::kYPlane),
      (*video_frame)->stride(VideoFrame::kYPlane),
      (*video_frame)->visible_data(VideoFrame::kUPlane),
      (*video_frame)->stride(VideoFrame::kUPlane),
      (*video_frame)->visible_data(VideoFrame::kVPlane),
      (*video_frame)->stride(VideoFrame::kVPlane), coded_size.width(),
      coded_size.height());

  return true;
}

}  // namespace media