C++ PlanarYCbCrImage::SetDataNoCopy方法代码示例

uint8_t *
AndroidMediaReader::ImageBufferCallback::CreateI420Image(size_t aWidth,
                                                         size_t aHeight)
{
  mImage = mImageContainer->CreateImage(ImageFormat::PLANAR_YCBCR);
  PlanarYCbCrImage *yuvImage = static_cast<PlanarYCbCrImage *>(mImage.get());

  if (!yuvImage) {
    NS_WARNING("Could not create I420 image");
    return nullptr;
  }

  size_t frameSize = aWidth * aHeight;

  // Allocate enough for one full resolution Y plane
  // and two quarter resolution Cb/Cr planes.
  uint8_t *buffer = yuvImage->AllocateAndGetNewBuffer(frameSize * 3 / 2);

  mozilla::layers::PlanarYCbCrData frameDesc;

  frameDesc.mYChannel = buffer;
  frameDesc.mCbChannel = buffer + frameSize;
  frameDesc.mCrChannel = buffer + frameSize * 5 / 4;

  frameDesc.mYSize = IntSize(aWidth, aHeight);
  frameDesc.mCbCrSize = IntSize(aWidth / 2, aHeight / 2);

  frameDesc.mYStride = aWidth;
  frameDesc.mCbCrStride = aWidth / 2;

  frameDesc.mYSkip = 0;
  frameDesc.mCbSkip = 0;
  frameDesc.mCrSkip = 0;

  frameDesc.mPicX = 0;
  frameDesc.mPicY = 0;
  frameDesc.mPicSize = IntSize(aWidth, aHeight);

  yuvImage->SetDataNoCopy(frameDesc);

  return buffer;
}

//.........这里部分代码省略.........
  if (!aImage && !aContainer) {
    // Create a dummy VideoData with no image. This gives us something to
    // send to media streams if necessary.
    nsAutoPtr<VideoData> v(new VideoData(aOffset,
                                         aTime,
                                         aDuration,
                                         aKeyframe,
                                         aTimecode,
                                         aInfo.mDisplay));
    return v.forget();
  }

  // The following situation should never happen unless there is a bug
  // in the decoder
  if (aBuffer.mPlanes[1].mWidth != aBuffer.mPlanes[2].mWidth ||
      aBuffer.mPlanes[1].mHeight != aBuffer.mPlanes[2].mHeight) {
    NS_ERROR("C planes with different sizes");
    return nullptr;
  }

  // The following situations could be triggered by invalid input
  if (aPicture.width <= 0 || aPicture.height <= 0) {
    NS_WARNING("Empty picture rect");
    return nullptr;
  }
  if (!ValidatePlane(aBuffer.mPlanes[0]) || !ValidatePlane(aBuffer.mPlanes[1]) ||
      !ValidatePlane(aBuffer.mPlanes[2])) {
    NS_WARNING("Invalid plane size");
    return nullptr;
  }

  // Ensure the picture size specified in the headers can be extracted out of
  // the frame we've been supplied without indexing out of bounds.
  CheckedUint32 xLimit = aPicture.x + CheckedUint32(aPicture.width);
  CheckedUint32 yLimit = aPicture.y + CheckedUint32(aPicture.height);
  if (!xLimit.isValid() || xLimit.value() > aBuffer.mPlanes[0].mStride ||
      !yLimit.isValid() || yLimit.value() > aBuffer.mPlanes[0].mHeight)
  {
    // The specified picture dimensions can't be contained inside the video
    // frame, we'll stomp memory if we try to copy it. Fail.
    NS_WARNING("Overflowing picture rect");
    return nullptr;
  }

  nsAutoPtr<VideoData> v(new VideoData(aOffset,
                                       aTime,
                                       aDuration,
                                       aKeyframe,
                                       aTimecode,
                                       aInfo.mDisplay));
  const YCbCrBuffer::Plane &Y = aBuffer.mPlanes[0];
  const YCbCrBuffer::Plane &Cb = aBuffer.mPlanes[1];
  const YCbCrBuffer::Plane &Cr = aBuffer.mPlanes[2];

  if (!aImage) {
    // Currently our decoder only knows how to output to PLANAR_YCBCR
    // format.
    ImageFormat format[2] = {PLANAR_YCBCR, GRALLOC_PLANAR_YCBCR};
    if (IsYV12Format(Y, Cb, Cr)) {
      v->mImage = aContainer->CreateImage(format, 2);
    } else {
      v->mImage = aContainer->CreateImage(format, 1);
    }
  } else {
    v->mImage = aImage;
  }

  if (!v->mImage) {
    return nullptr;
  }
  NS_ASSERTION(v->mImage->GetFormat() == PLANAR_YCBCR ||
               v->mImage->GetFormat() == GRALLOC_PLANAR_YCBCR,
               "Wrong format?");
  PlanarYCbCrImage* videoImage = static_cast<PlanarYCbCrImage*>(v->mImage.get());

  PlanarYCbCrData data;
  data.mYChannel = Y.mData + Y.mOffset;
  data.mYSize = gfxIntSize(Y.mWidth, Y.mHeight);
  data.mYStride = Y.mStride;
  data.mYSkip = Y.mSkip;
  data.mCbChannel = Cb.mData + Cb.mOffset;
  data.mCrChannel = Cr.mData + Cr.mOffset;
  data.mCbCrSize = gfxIntSize(Cb.mWidth, Cb.mHeight);
  data.mCbCrStride = Cb.mStride;
  data.mCbSkip = Cb.mSkip;
  data.mCrSkip = Cr.mSkip;
  data.mPicX = aPicture.x;
  data.mPicY = aPicture.y;
  data.mPicSize = gfxIntSize(aPicture.width, aPicture.height);
  data.mStereoMode = aInfo.mStereoMode;

  videoImage->SetDelayedConversion(true);
  if (!aImage) {
    videoImage->SetData(data);
  } else {
    videoImage->SetDataNoCopy(data);
  }

  return v.forget();
}

int
FFmpegH264Decoder::AllocateYUV420PVideoBuffer(AVCodecContext* aCodecContext,
                                              AVFrame* aFrame)
{
  // Older versions of ffmpeg require that edges be allocated* around* the
  // actual image.
  int edgeWidth = avcodec_get_edge_width();
  int decodeWidth = aCodecContext->width + edgeWidth * 2;
  int decodeHeight = aCodecContext->height + edgeWidth * 2;

  // Align width and height to possibly speed up decode.
  int stride_align[AV_NUM_DATA_POINTERS];
  avcodec_align_dimensions2(aCodecContext, &decodeWidth, &decodeHeight,
                            stride_align);

  // Get strides for each plane.
  av_image_fill_linesizes(aFrame->linesize, aCodecContext->pix_fmt,
                          decodeWidth);

  // Let FFmpeg set up its YUV plane pointers and tell us how much memory we
  // need.
  // Note that we're passing |nullptr| here as the base address as we haven't
  // allocated our image yet. We will adjust |aFrame->data| below.
  size_t allocSize =
    av_image_fill_pointers(aFrame->data, aCodecContext->pix_fmt, decodeHeight,
                           nullptr /* base address */, aFrame->linesize);

  nsRefPtr<Image> image =
    mImageContainer->CreateImage(ImageFormat::PLANAR_YCBCR);
  PlanarYCbCrImage* ycbcr = reinterpret_cast<PlanarYCbCrImage*>(image.get());
  uint8_t* buffer = ycbcr->AllocateAndGetNewBuffer(allocSize);

  if (!buffer) {
    NS_WARNING("Failed to allocate buffer for FFmpeg video decoding");
    return -1;
  }

  // Now that we've allocated our image, we can add its address to the offsets
  // set by |av_image_fill_pointers| above. We also have to add |edgeWidth|
  // pixels of padding here.
  for (uint32_t i = 0; i < AV_NUM_DATA_POINTERS; i++) {
    // The C planes are half the resolution of the Y plane, so we need to halve
    // the edge width here.
    uint32_t planeEdgeWidth = edgeWidth / (i ? 2 : 1);

    // Add buffer offset, plus a horizontal bar |edgeWidth| pixels high at the
    // top of the frame, plus |edgeWidth| pixels from the left of the frame.
    aFrame->data[i] += reinterpret_cast<ptrdiff_t>(
      buffer + planeEdgeWidth * aFrame->linesize[i] + planeEdgeWidth);
  }

  // Unused, but needs to be non-zero to keep ffmpeg happy.
  aFrame->type = GECKO_FRAME_TYPE;

  aFrame->extended_data = aFrame->data;
  aFrame->width = aCodecContext->width;
  aFrame->height = aCodecContext->height;

  mozilla::layers::PlanarYCbCrData data;
  PlanarYCbCrDataFromAVFrame(data, aFrame);
  ycbcr->SetDataNoCopy(data);

  mCurrentImage.swap(image);

  return 0;
}