Mattia Iavarone
5 years ago
parent
06d805cb72
commit
e96c9f0846
@ -0,0 +1,96 @@ |
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package com.otaliastudios.cameraview.internal.utils; |
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import android.graphics.ImageFormat; |
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import android.graphics.Rect; |
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import android.media.Image; |
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import com.otaliastudios.cameraview.size.AspectRatio; |
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import com.otaliastudios.cameraview.size.Size; |
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import java.nio.ByteBuffer; |
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import androidx.annotation.NonNull; |
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import androidx.annotation.RequiresApi; |
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/** |
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* Conversions for {@link android.media.Image}s into byte arrays. |
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*/ |
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@RequiresApi(19) |
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public class ImageHelper { |
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// https://stackoverflow.com/a/52740776/4288782
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public static void convertToNV21(@NonNull Image image, @NonNull byte[] result) { |
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if (image.getFormat() != ImageFormat.YUV_420_888) { |
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throw new IllegalStateException("CAn only convert from YUV_420_888."); |
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} |
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int width = image.getWidth(); |
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int height = image.getHeight(); |
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int ySize = width * height; |
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int uvSize = width * height / 4; |
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ByteBuffer yBuffer = image.getPlanes()[0].getBuffer(); // Y
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ByteBuffer uBuffer = image.getPlanes()[1].getBuffer(); // U
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ByteBuffer vBuffer = image.getPlanes()[2].getBuffer(); // V
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int rowStride = image.getPlanes()[0].getRowStride(); |
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if (image.getPlanes()[0].getPixelStride() != 1) { |
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throw new AssertionError("Something wrong in convertToNV21"); |
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} |
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int pos = 0; |
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if (rowStride == width) { // likely
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yBuffer.get(result, 0, ySize); |
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pos += ySize; |
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} |
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else { |
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int yBufferPos = width - rowStride; // not an actual position
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for (; pos<ySize; pos+=width) { |
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yBufferPos += rowStride - width; |
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yBuffer.position(yBufferPos); |
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yBuffer.get(result, pos, width); |
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} |
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} |
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rowStride = image.getPlanes()[2].getRowStride(); |
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int pixelStride = image.getPlanes()[2].getPixelStride(); |
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if (rowStride != image.getPlanes()[1].getRowStride()) { |
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throw new AssertionError("Something wrong in convertToNV21"); |
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} |
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if (pixelStride != image.getPlanes()[1].getPixelStride()) { |
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throw new AssertionError("Something wrong in convertToNV21"); |
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} |
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if (pixelStride == 2 && rowStride == width && uBuffer.get(0) == vBuffer.get(1)) { |
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// maybe V an U planes overlap as per NV21, which means vBuffer[1] is alias of uBuffer[0]
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byte savePixel = vBuffer.get(1); |
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vBuffer.put(1, (byte)0); |
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if (uBuffer.get(0) == 0) { |
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vBuffer.put(1, (byte)255); |
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//noinspection ConstantConditions
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if (uBuffer.get(0) == 255) { |
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vBuffer.put(1, savePixel); |
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vBuffer.get(result, ySize, uvSize); |
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return; // shortcut
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} |
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} |
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// unfortunately, the check failed. We must save U and V pixel by pixel
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vBuffer.put(1, savePixel); |
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} |
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// other optimizations could check if (pixelStride == 1) or (pixelStride == 2),
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// but performance gain would be less significant
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for (int row=0; row<height/2; row++) { |
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for (int col=0; col<width/2; col++) { |
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int vuPos = col*pixelStride + row*rowStride; |
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result[pos++] = vBuffer.get(vuPos); |
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result[pos++] = uBuffer.get(vuPos); |
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} |
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} |
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} |
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} |
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