在Android camera2下将YUV_420_888转换为位图的图像不正确

回答我自己的问题,实际的问题是,我怀疑我是如何将图像平面转换成ByteBuffer的。接下来是解决方案,它应该适用于NV21和;YV12。由于YUV数据已经在不同的平面中出现,因此只需要根据行和像素步长以正确的方式获取数据。还需要对数据传递到RenderScript内部的方式进行一些小的修改。

注意:对于生产优化的onImageAvailable()不间断流,在进行转换之前,应将图像字节数据复制到单独的缓冲区,并在单独的线程中执行转换(取决于您的要求)。但由于这不是问题的一部分,在下一个代码中,转换直接放在onImageAvailable()中,以简化答案。如果任何人需要知道如何复制图像数据,请创建一个新的问题,让我知道,这样我将分享我的代码。

@Override
public void onImageAvailable(ImageReader reader)
{
    // Get the YUV data

    final Image image = reader.acquireLatestImage();
    final ByteBuffer yuvBytes = this.imageToByteBuffer(image);

    // Convert YUV to RGB

    final RenderScript rs = RenderScript.create(this.mContext);

    final Bitmap        bitmap     = Bitmap.createBitmap(image.getWidth(), image.getHeight(), Bitmap.Config.ARGB_8888);
    final Allocation allocationRgb = Allocation.createFromBitmap(rs, bitmap);

    final Allocation allocationYuv = Allocation.createSized(rs, Element.U8(rs), yuvBytes.array().length);
    allocationYuv.copyFrom(yuvBytes.array());

    ScriptIntrinsicYuvToRGB scriptYuvToRgb = ScriptIntrinsicYuvToRGB.create(rs, Element.U8_4(rs));
    scriptYuvToRgb.setInput(allocationYuv);
    scriptYuvToRgb.forEach(allocationRgb);

    allocationRgb.copyTo(bitmap);

    // Release

    bitmap.recycle();

    allocationYuv.destroy();
    allocationRgb.destroy();
    rs.destroy();

    image.close();
}

private ByteBuffer imageToByteBuffer(final Image image)
{
    final Rect crop   = image.getCropRect();
    final int  width  = crop.width();
    final int  height = crop.height();

    final Image.Plane[] planes     = image.getPlanes();
    final byte[]        rowData    = new byte[planes[0].getRowStride()];
    final int           bufferSize = width * height * ImageFormat.getBitsPerPixel(ImageFormat.YUV_420_888) / 8;
    final ByteBuffer    output     = ByteBuffer.allocateDirect(bufferSize);

    int channelOffset = 0;
    int outputStride = 0;

    for (int planeIndex = 0; planeIndex < 3; planeIndex++)
    {
        if (planeIndex == 0)
        {
            channelOffset = 0;
            outputStride = 1;
        }
        else if (planeIndex == 1)
        {
            channelOffset = width * height + 1;
            outputStride = 2;
        }
        else if (planeIndex == 2)
        {
            channelOffset = width * height;
            outputStride = 2;
        }

        final ByteBuffer buffer      = planes[planeIndex].getBuffer();
        final int        rowStride   = planes[planeIndex].getRowStride();
        final int        pixelStride = planes[planeIndex].getPixelStride();

        final int shift         = (planeIndex == 0) ? 0 : 1;
        final int widthShifted  = width >> shift;
        final int heightShifted = height >> shift;

        buffer.position(rowStride * (crop.top >> shift) + pixelStride * (crop.left >> shift));

        for (int row = 0; row < heightShifted; row++)
        {
            final int length;

            if (pixelStride == 1 && outputStride == 1)
            {
                length = widthShifted;
                buffer.get(output.array(), channelOffset, length);
                channelOffset += length;
            }
            else
            {
                length = (widthShifted - 1) * pixelStride + 1;
                buffer.get(rowData, 0, length);

                for (int col = 0; col < widthShifted; col++)
                {
                    output.array()[channelOffset] = rowData[col * pixelStride];
                    channelOffset += outputStride;
                }
            }

            if (row < heightShifted - 1)
            {
                buffer.position(buffer.position() + rowStride - length);
            }
        }
    }

    return output;
}

RenderScript支持YUV_420_888作为ScriptIntrinsicYuvToRGB的源代码

1. 创建分配(&A);ScriptIntrinsicYuvToRGB

   RenderScript renderScript = RenderScript.create(this);
   ScriptIntrinsicYuvToRGB mScriptIntrinsicYuvToRGB = ScriptIntrinsicYuvToRGB.create(renderScript, Element.YUV(renderScript));
   Allocation mAllocationInYUV = Allocation.createTyped(renderScript, new Type.Builder(renderScript, Element.YUV(renderScript)).setYuvFormat(ImageFormat.YUV_420_888).setX(480).setY(640).create(), Allocation.USAGE_IO_INPUT | Allocation.USAGE_SCRIPT);
   Allocation mAllocationOutRGB = Allocation.createTyped(renderScript, Type.createXY(renderScript, Element.RGBA_8888(renderScript), 480, 640), Allocation.USAGE_SCRIPT | Allocation.USAGE_IO_OUTPUT);
   

2. 设置分配。getSurface()从摄像机接收图像数据

   final CaptureRequest.Builder captureRequest = session.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
   captureRequest.addTarget(mAllocationInYUV.getSurface());
   

3. 输出到TextureView、ImageReader或SurfaceView

   mAllocationOutRGB.setSurface(new Surface(mTextureView.getSurfaceTexture()));
   mAllocationInYUV.setOnBufferAvailableListener(new Allocation.OnBufferAvailableListener() {
       @Override
       public void onBufferAvailable(Allocation a) {
           a.ioReceive();
           mScriptIntrinsicYuvToRGB.setInput(a);
           mScriptIntrinsicYuvToRGB.forEach(mAllocationOutRGB);
           mAllocationOutRGB.ioSend();
       }
   });
   

没有直接的方法将YUV_420_888摄像机帧复制到RS分配中。实际上,截至今天,Renderscript does not support this format .

如果您知道,在引擎盖下,您的帧是NV21或YV12-您可以将整个ByteBuffer复制到一个数组,并将其传递给RS分配。