fune/dom/media/platforms/agnostic/BlankDecoderModule.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "BlankDecoderModule.h"

#include "mozilla/CheckedInt.h"
#include "mozilla/UniquePtrExtensions.h"
#include "mozilla/RefPtr.h"
#include "mozilla/gfx/Rect.h"
#include "mozilla/gfx/Point.h"
#include "ImageContainer.h"
#include "MediaData.h"
#include "MediaInfo.h"
#include "VideoUtils.h"

namespace mozilla {

BlankVideoDataCreator::BlankVideoDataCreator(
    uint32_t aFrameWidth, uint32_t aFrameHeight,
    layers::ImageContainer* aImageContainer)
    : mFrameWidth(aFrameWidth),
      mFrameHeight(aFrameHeight),
      mImageContainer(aImageContainer) {
  mInfo.mDisplay = gfx::IntSize(mFrameWidth, mFrameHeight);
  mPicture = gfx::IntRect(0, 0, mFrameWidth, mFrameHeight);
}

already_AddRefed<MediaData> BlankVideoDataCreator::Create(
    MediaRawData* aSample) {
  // Create a fake YUV buffer in a 420 format. That is, an 8bpp Y plane,
  // with a U and V plane that are half the size of the Y plane, i.e 8 bit,
  // 2x2 subsampled. Have the data pointer of each frame point to the
  // first plane, they'll always be zero'd memory anyway.
  const CheckedUint32 size = CheckedUint32(mFrameWidth) * mFrameHeight;
  if (!size.isValid()) {
    // Overflow happened.
    return nullptr;
  }
  auto frame = MakeUniqueFallible<uint8_t[]>(size.value());
  if (!frame) {
    return nullptr;
  }
  memset(frame.get(), 0, mFrameWidth * mFrameHeight);
  VideoData::YCbCrBuffer buffer;

  // Y plane.
  buffer.mPlanes[0].mData = frame.get();
  buffer.mPlanes[0].mStride = mFrameWidth;
  buffer.mPlanes[0].mHeight = mFrameHeight;
  buffer.mPlanes[0].mWidth = mFrameWidth;
  buffer.mPlanes[0].mSkip = 0;

  // Cb plane.
  buffer.mPlanes[1].mData = frame.get();
  buffer.mPlanes[1].mStride = (mFrameWidth + 1) / 2;
  buffer.mPlanes[1].mHeight = (mFrameHeight + 1) / 2;
  buffer.mPlanes[1].mWidth = (mFrameWidth + 1) / 2;
  buffer.mPlanes[1].mSkip = 0;

  // Cr plane.
  buffer.mPlanes[2].mData = frame.get();
  buffer.mPlanes[2].mStride = (mFrameWidth + 1) / 2;
  buffer.mPlanes[2].mHeight = (mFrameHeight + 1) / 2;
  buffer.mPlanes[2].mWidth = (mFrameWidth + 1) / 2;
  buffer.mPlanes[2].mSkip = 0;

  buffer.mChromaSubsampling = gfx::ChromaSubsampling::HALF_WIDTH_AND_HEIGHT;
  buffer.mYUVColorSpace = gfx::YUVColorSpace::BT601;
  buffer.mColorPrimaries = gfx::ColorSpace2::BT709;

  return VideoData::CreateAndCopyData(mInfo, mImageContainer, aSample->mOffset,
                                      aSample->mTime, aSample->mDuration,
                                      buffer, aSample->mKeyframe,
                                      aSample->mTime, mPicture, nullptr);
}

BlankAudioDataCreator::BlankAudioDataCreator(uint32_t aChannelCount,
                                             uint32_t aSampleRate)
    : mFrameSum(0), mChannelCount(aChannelCount), mSampleRate(aSampleRate) {}

already_AddRefed<MediaData> BlankAudioDataCreator::Create(
    MediaRawData* aSample) {
  // Convert duration to frames. We add 1 to duration to account for
  // rounding errors, so we get a consistent tone.
  CheckedInt64 frames =
      UsecsToFrames(aSample->mDuration.ToMicroseconds() + 1, mSampleRate);
  if (!frames.isValid() || !mChannelCount || !mSampleRate ||
      frames.value() > (UINT32_MAX / mChannelCount)) {
    return nullptr;
  }
  AlignedAudioBuffer samples(frames.value() * mChannelCount);
  if (!samples) {
    return nullptr;
  }
  // Fill the sound buffer with an A4 tone.
  static const float pi = 3.14159265f;
  static const float noteHz = 440.0f;
  for (int i = 0; i < frames.value(); i++) {
    float f = sin(2 * pi * noteHz * mFrameSum / mSampleRate);
    for (unsigned c = 0; c < mChannelCount; c++) {
      samples[i * mChannelCount + c] = AudioDataValue(f);
    }
    mFrameSum++;
  }
  RefPtr<AudioData> data(new AudioData(aSample->mOffset, aSample->mTime,
                                       std::move(samples), mChannelCount,
                                       mSampleRate));
  return data.forget();
}

already_AddRefed<MediaDataDecoder> BlankDecoderModule::CreateVideoDecoder(
    const CreateDecoderParams& aParams) {
  const VideoInfo& config = aParams.VideoConfig();
  UniquePtr<DummyDataCreator> creator = MakeUnique<BlankVideoDataCreator>(
      config.mDisplay.width, config.mDisplay.height, aParams.mImageContainer);
  RefPtr<MediaDataDecoder> decoder = new DummyMediaDataDecoder(
      std::move(creator), "blank media data decoder"_ns, aParams);
  return decoder.forget();
}

already_AddRefed<MediaDataDecoder> BlankDecoderModule::CreateAudioDecoder(
    const CreateDecoderParams& aParams) {
  const AudioInfo& config = aParams.AudioConfig();
  UniquePtr<DummyDataCreator> creator =
      MakeUnique<BlankAudioDataCreator>(config.mChannels, config.mRate);
  RefPtr<MediaDataDecoder> decoder = new DummyMediaDataDecoder(
      std::move(creator), "blank media data decoder"_ns, aParams);
  return decoder.forget();
}

media::DecodeSupportSet BlankDecoderModule::SupportsMimeType(
    const nsACString& aMimeType, DecoderDoctorDiagnostics* aDiagnostics) const {
  return media::DecodeSupport::SoftwareDecode;
}

/* static */
already_AddRefed<PlatformDecoderModule> BlankDecoderModule::Create() {
  return MakeAndAddRef<BlankDecoderModule>();
}

}  // namespace mozilla