YUV（NV21）图像皈依位图 [英] Yuv (NV21) image convertion to bitmap

问题描述

我试图捕捉摄像头preVIEW图片及它的一些图纸。问题是，我从相机preVIEW大约只有3-4 fps的绘画，有一半的帧处理时间接收和解码NV21形象，转换为位图。我有一个code做这个任务，这是我的另一个问题堆栈中。它似乎没有要快，但我不知道，如何优化它。大约需要100-150毫秒。三星注3，图像尺寸1920×1080。我怎样才能使它工作得更快？

I am trying to capture images from camera preview and do some drawing on it. The problem is, I have only about 3-4 fps of drawing, and half of the frame processing time is receiving and decoding NV21 image from camera preview and converting to bitmap. I have a code to do this task, which I found on another stack question. It does not seem to be fast, but I do not know, how to optimize it. It takes about 100-150 ms. on Samsung Note 3, image size 1920x1080. How can I make it work faster?

code：

public Bitmap curFrameImage(byte[] data, Camera camera)
{
    Camera.Parameters parameters = camera.getParameters();
    int imageFormat = parameters.getPreviewFormat();

    if (imageFormat == ImageFormat.NV21)
    {
        YuvImage img = new YuvImage(data, ImageFormat.NV21, prevSizeW, prevSizeH, null);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        img.compressToJpeg(new android.graphics.Rect(0, 0, img.getWidth(), img.getHeight()), 50, out);
        byte[] imageBytes = out.toByteArray();
        return BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
    }
    else
    {
        Log.i(TAG, "Preview image not NV21");
        return null;
    }
}

图像的最终格式必须是位图，这样的话我可以做它的处理。我试着Camera.Parameters.set previewFormat设置为RGB_565，但不能指定相机PARAMS相机，我读过也是NV21是唯一可用的格式。我不知道这件事，是否有可能找到这些格式更改的解决方案。

The final format of image has to be bitmap, so I could then do processing on it. I've tried to set Camera.Parameters.setPreviewFormat to RGB_565, but could not assign camera params to camera, I've read also that NV21 is the only available format. I am not sure about that, whether it is possible to find solution in these format changes.

感谢您提前。

推荐答案

感谢您，亚历克斯·科恩，帮我做这做皈依更快。我实现了你的建议的方法（RenderScript内部函数）。这code，与RenderScript内在制成，转换YUV图像为位图一下〜5倍的速度。 previous code拿了100-150毫秒。三星注3，这需要15-30左右。 如果有人需要做同样的任务，有code：

Thank you, Alex Cohn, for helping me to do make this convertion faster. I implemented your suggested methods (RenderScript intrinsics). This code, made with RenderScript intrinsics, converts YUV image to bitmap about ~5 times faster. Previous code took 100-150 ms. on Samsung Note 3, this takes 15-30 or so. If someone needs to do the same task, there is the code:

这些将被使用：

private RenderScript rs;
private ScriptIntrinsicYuvToRGB yuvToRgbIntrinsic;
private Type.Builder yuvType, rgbaType;
private Allocation in, out;

在上创建函数初始化我..：

In on create function I initialize..:

rs = RenderScript.create(this);
yuvToRgbIntrinsic = ScriptIntrinsicYuvToRGB.create(rs, Element.U8_4(rs));

和整体上previewFrame看起来像这样（我在这里接收和转换图像）：

And the whole onPreviewFrame looks like this (here I receive and convert the image):

if (yuvType == null)
{
    yuvType = new Type.Builder(rs, Element.U8(rs)).setX(dataLength);
    in = Allocation.createTyped(rs, yuvType.create(), Allocation.USAGE_SCRIPT);

    rgbaType = new Type.Builder(rs, Element.RGBA_8888(rs)).setX(prevSizeW).setY(prevSizeH);
    out = Allocation.createTyped(rs, rgbaType.create(), Allocation.USAGE_SCRIPT);
}

in.copyFrom(data);

yuvToRgbIntrinsic.setInput(in);
yuvToRgbIntrinsic.forEach(out);

Bitmap bmpout = Bitmap.createBitmap(prevSizeW, prevSizeH, Bitmap.Config.ARGB_8888);
out.copyTo(bmpout);

这篇关于YUV（NV21）图像皈依位图的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！