Develop Reference

Android : Preview frame, converted from YCbCr_420_SP (NV21) format to RGB render correct picture but in green

I post this question as I didn’t find answers solving my issues in the following posts :
Converting preview frame to bitmap
Android decodeYUV420SP results in green images?
Displaying YUV Image in Android
I got my data and cameraResolution (after selecting BestPreviewSize) from :
public void onPreviewFrame(byte[] data, Camera camera) {
Point cameraResolution = configManager.getCameraResolution();
Handler thePreviewHandler = previewHandler;
if (cameraResolution != null && thePreviewHandler != null) {
Message message = thePreviewHandler.obtainMessage(previewMessage, cameraResolution.x,
cameraResolution.y, data);
message.sendToTarget();
previewHandler = null;
} else {
Log.d(TAG, "Got preview callback, but no handler or resolution available");
}
}
Later from conversion to RGB, I use :
int[] pixels=new int[yuvData.length];
// int size = dataWidth*dataHeight;
// int[] pixels=new int[size]; replacing yuvData.length by size is not working too
pixels=decodeYUV420SP(pixels,yuvData, dataWidth, dataHeight);
Bitmap bitmap = Bitmap.createBitmap(dataWidth, dataHeight, Bitmap.Config.RGB_565);
bitmap.setPixels(pixels, 0, dataWidth, 0, 0, dataWidth, dataHeight);
I tried 2 methods, one with RenderScript and one with decodeYUV420SP:
public Bitmap convertYUV420_NV21toRGB8888_RenderScript(byte [] data,int W, int H, CaptureActivityOCR fragment) {
// https://stackoverflow.com/questions/20358803/how-to-use-scriptintrinsicyuvtorgb-converting-byte-yuv-to-byte-rgba
RenderScript rs;
ScriptIntrinsicYuvToRGB yuvToRgbIntrinsic;
rs = RenderScript.create(fragment.getActivity());
yuvToRgbIntrinsic = ScriptIntrinsicYuvToRGB.create(rs, Element.U8_4(rs)); //Create an intrinsic for converting YUV to RGB.
Type.Builder yuvType = new Type.Builder(rs, Element.U8(rs)).setX(data.length);
Allocation in = Allocation.createTyped(rs, yuvType.create(), Allocation.USAGE_SCRIPT); //an Allocation will be populated with empty data when it is first created
Type.Builder rgbaType = new Type.Builder(rs, Element.RGBA_8888(rs)).setX(W).setY(H);
Allocation out = Allocation.createTyped(rs, rgbaType.create(), Allocation.USAGE_SCRIPT); //an Allocation will be populated with empty data when it is first created
in.copyFrom(data);//Populate Allocations with data.
yuvToRgbIntrinsic.setInput(in); //Set the input yuv allocation, must be U8(RenderScript).
yuvToRgbIntrinsic.forEach(out); //Launch the appropriate kernels,Convert the image to RGB.
Bitmap bmpout = Bitmap.createBitmap(W, H, Bitmap.Config.ARGB_8888);
out.copyTo(bmpout); //Copy data out of Allocation objects.
return bmpout;
}
or
int[] decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height) {
Log.e("camera", " decodeYUV420SP ");
// TODO Auto-generated method stub
final int frameSize = width * height;
for (int j = 0, yp = 0; j < height; j++) {
int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
int y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0) y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
int y1192 = 1192 * y;
int r = (y1192 + 1634 * v);
int g = (y1192 - 833 * v - 400 * u);
int b = (y1192 + 2066 * u);
if (r < 0) r = 0; else if (r > 262143) r = 262143;
if (g < 0) g = 0; else if (g > 262143) g = 262143;
if (b < 0) b = 0; else if (b > 262143) b = 262143;
rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
}
}
return rgb;
}
But still I don't know why I got some good image but in green. (I have another similar method in black and white which is working)
In addition of the links above,i tried all posts linked to this subject on SO , so If someone could help for another tip please? I may be confused with the size to apply?
Somewhere after OnPreviewFrame method and before conversion to RGB method, I use another method with instruction below as I need to rotate the data received. I am wondering if this is not the origin of issue :
byte[] rotatedData = new byte[data.length];
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++)
rotatedData[x * height + height - y - 1] = data[x + y * width];
}
int tmp = width;
width = height;
height = tmp;
Please help me?

I think your rotation routine is wrong.
It works for Luma (Y), hence you get good results for black and white picture but not for chroma. If width and height are dimensions of your picture you do not rotate chroma values at all.
So you will need to add second loop for chroma and move pairs of bytes (V and U).
If you tried it without this rotation and you still have greenish picture the problem might be also in your decodeYUV420SP function.
There is not one universal formula for yuv to rgba conversion. It must match the opposite one.
Look here http://www.codeproject.com/Articles/402391/RGB-to-YUV-conversion-with-different-chroma-sampli and here http://www.fourcc.org/fccyvrgb.php
This one works for me
B = 1.164(Y - 16) + 2.018(U - 128)
G = 1.164(Y - 16) - 0.813(V - 128) - 0.391(U - 128)
R = 1.164(Y - 16) + 1.596(V - 128)
It seems to be the same as you are using only float version so you may try other.

I suggest to rotate the bitmap after RenderScript rotation:
if (bmpout == null) {
bmpout = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
}
rgbaAllocation.copyTo(bmpout);
if (matrixPostRotate90 == null) {
matrixPostRotate90 = new Matrix();
matrixPostRotate90.postRotate(90);
}
Bitmap rotatedBitmap = Bitmap.createBitmap(bmpout, 0, 0, w, h, matrixPostRotate90, true);

Extract frames from a video in real-time android

I'm doing an app to record a video. What I would like is that when the app is recording the video, each frame is also saved in an arraylist of RGB values in order to extract particular information from it. I know that the two processes (video recording and extraction of frames) are asynchronous, but this is not a problem: the process of extraction can finish after the video recording.
Can someone tell me how I can extract the frames from the video?
Thanks very much.

Using the camera object you can override a function setPreviewCallback. from that function you would get an array of byte data. Which you can convert to bitmap or you can save them in an array of array.
Assuming that you were extends SurfaceView and Implements SurfaceHolder.Callback
Code looks like,
mCamera.setPreviewCallback(new PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera camera) {
//do some operations using data
}
});
If you want to get the RGB value you can use this function,
static public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width,
int height) {
final int frameSize = width * height;
for (int j = 0, yp = 0; j < height; j++) {
int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
int y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
int y1192 = 1192 * y;
int r = (y1192 + 1634 * v);
int g = (y1192 - 833 * v - 400 * u);
int b = (y1192 + 2066 * u);
if (r < 0)
r = 0;
else if (r > 262143)
r = 262143;
if (g < 0)
g = 0;
else if (g > 262143)
g = 262143;
if (b < 0)
b = 0;
else if (b > 262143)
b = 262143;
rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000)
| ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
}
}
}
I think this is what you want as an answer. If i am wrong, please let me know whats is your actual requirement
For getting the green value, you can use the below code,
static public void calculateColor(int[] rgb, int[] color,
int width, int height, int component) {
for (int bin = 0; bin < 256; bin++) {
color[bin] = 0;
} // bin
int start = 0;
int end = width * height;
if (component == 0) // red
{
for (int pix = start; pix < end; pix += 3) {
int pixVal = (rgb[pix] >> 16) & 0xff;
color[pixVal]++;
} // pix
} else if (component == 1) // green
{
for (int pix = start; pix < end; pix += 3) {
int pixVal = (rgb[pix] >> 8) & 0xff;
color[pixVal]++;
} // pix
} else // blue
{
for (int pix = start; pix < end; pix += 3) {
int pixVal = rgb[pix] & 0xff;
color[pixVal]++;
} // pix
}
}
Calling this function would return the value of green for every pixel. If you wants the green value for a particular pixel, you have to modify this code.

Sample code for extracting frames from a .mp4 file can be found on the bigflake site. It uses MediaCodec, available on API 16+. If you need to run on older devices, your best bet is probably ffmpeg.
RGB data requires 3 bytes per pixel. 10 seconds of 720p video at 30 fps will require 1280*720*3*30*10 = 791 megabytes. Unless your video frames are fairly small, holding on to a large number of them may not be practical (or possible).

It seems to me you want to get the image while video recording is ongoing.
In that case you will need to look into Build your camera app. This page describes how to record a video using android camera class.
You can then get yuv images through Camera preview callback.

Android decodeYUV420SP results in green images?

Ok so my question is pretty much identical to this:
Converting preview frame to bitmap
However his answer is no good, and trying to use it doesn't solve my problem.
So what I'm trying to do at the moment is to send each frame as a bitmap to a method to detect if there are any faces, but first I need to create a bitmap which means I have to use the decodeYUV420sp method, which doesn't seem to be working properly and all my images just come out as a green and yellow tie dye looking image. Here is my code:
This is from onPreviewFrame:
Parameters parameters = cam.getParameters();
Integer width = parameters.getPreviewSize().width;
Integer height = parameters.getPreviewSize().height;
Log.i("preview size: ", String.valueOf(width) + "x" + String.valueOf(height));
int[] mIntArray = new int[width*height];
// Decode Yuv data to integer array
decodeYUV420SP(mIntArray, data, width, height);
//Initialize the bitmap, with the replaced color
Bitmap bmp = Bitmap.createBitmap(mIntArray, width, height, Bitmap.Config.ARGB_8888);
saveImage(bmp);
This is decodeYUV method:
static public void decodeYUV420SP(int[] rgba, byte[] yuv420sp, int width,
int height) {
final int frameSize = width * height;
for (int j = 0, yp = 0; j < height; j++) {
int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
int y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
int y1192 = 1192 * y;
int r = (y1192 + 1634 * v);
int g = (y1192 - 833 * v - 400 * u);
int b = (y1192 + 2066 * u);
if (r < 0)
r = 0;
else if (r > 262143)
r = 262143;
if (g < 0)
g = 0;
else if (g > 262143)
g = 262143;
if (b < 0)
b = 0;
else if (b > 262143)
b = 262143;
// rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) &
// 0xff00) | ((b >> 10) & 0xff);
// rgba, divide 2^10 ( >> 10)
rgba[yp] = ((r << 14) & 0xff000000) | ((g << 6) & 0xff0000)
| ((b >> 2) | 0xff00);
}
}
}
and this is the method I'm calling to save the bitmaps to see what they look like:
private void saveImage(Bitmap bmp) {
File myDir=new File("/sdcard/saved_images");
myDir.mkdirs();
Random generator = new Random();
int n = 10000;
n = generator.nextInt(n);
String fname = "Image-"+ n +".jpg";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
bmp.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
Here is a resulting image:
https://docs.google.com/drawings/d/1kyIvb4oHHInW_c71mjfFSVCxVopBgBWX3k1OR_nMgRA/edit

The key point here is that there are a (large) number of different YUV encodings, and an even larger list of names used for them. A lot of information about all the different variants (and their names) is given by fourcc, although 420SP isn't mentionned explicitly. Looking here, it looks like:
420P is the same as YV12. 'P' appears to stand for planar: there are three 'planes' of data one after the other: Y, U and then V. (Or, in YV21, which is also a 420P encoding, Y, V and then U.)
420SP is the same as NV12 (which is the same as NV21 but with U and V swapped around). 'SP' appears to stand for 'semi-planar', and so '420SP' could, technically, refer to either NV21 or NV12.
In this case, therefore, you are decoding NV12 (as opposed to NV21) and so the order of U and V is swapped around compared to the answer you quote in your answer. In case it helps, I have provided some code here.

Ok so the problem was the decodeYUV method which I got from a different stackoverflow post here:
Converting YUV->RGB(Image processing)->YUV during onPreviewFrame in android? didn't quite work.
But I replaced that with what I think must be the original decodeYUV method from here:
http://code.google.com/p/android/issues/detail?id=823
an

Converting YUV->RGB(Image processing)->YUV during onPreviewFrame in android?

I am capturing image using SurfaceView and getting Yuv Raw preview data in public void onPreviewFrame4(byte[] data, Camera camera)
I have to perform some image preprocessing in onPreviewFrame so i need to convert Yuv preview data to RGB data than image preprocessing and back to Yuv data.
I have used both function for encoding and decoding Yuv data to RGB as following :
public void onPreviewFrame(byte[] data, Camera camera) {
Point cameraResolution = configManager.getCameraResolution();
if (data != null) {
Log.i("DEBUG", "data Not Null");
// Preprocessing
Log.i("DEBUG", "Try For Image Processing");
Camera.Parameters mParameters = camera.getParameters();
Size mSize = mParameters.getPreviewSize();
int mWidth = mSize.width;
int mHeight = mSize.height;
int[] mIntArray = new int[mWidth * mHeight];
// Decode Yuv data to integer array
decodeYUV420SP(mIntArray, data, mWidth, mHeight);
// Converting int mIntArray to Bitmap and
// than image preprocessing
// and back to mIntArray.
// Encode intArray to Yuv data
encodeYUV420SP(data, mIntArray, mWidth, mHeight);
}
}
static public void decodeYUV420SP(int[] rgba, byte[] yuv420sp, int width,
int height) {
final int frameSize = width * height;
for (int j = 0, yp = 0; j < height; j++) {
int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
int y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
int y1192 = 1192 * y;
int r = (y1192 + 1634 * v);
int g = (y1192 - 833 * v - 400 * u);
int b = (y1192 + 2066 * u);
if (r < 0)
r = 0;
else if (r > 262143)
r = 262143;
if (g < 0)
g = 0;
else if (g > 262143)
g = 262143;
if (b < 0)
b = 0;
else if (b > 262143)
b = 262143;
// rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) &
// 0xff00) | ((b >> 10) & 0xff);
// rgba, divide 2^10 ( >> 10)
rgba[yp] = ((r << 14) & 0xff000000) | ((g << 6) & 0xff0000)
| ((b >> 2) | 0xff00);
}
}
}
static public void encodeYUV420SP_original(byte[] yuv420sp, int[] rgba,
int width, int height) {
final int frameSize = width * height;
int[] U, V;
U = new int[frameSize];
V = new int[frameSize];
final int uvwidth = width / 2;
int r, g, b, y, u, v;
for (int j = 0; j < height; j++) {
int index = width * j;
for (int i = 0; i < width; i++) {
r = (rgba[index] & 0xff000000) >> 24;
g = (rgba[index] & 0xff0000) >> 16;
b = (rgba[index] & 0xff00) >> 8;
// rgb to yuv
y = (66 * r + 129 * g + 25 * b + 128) >> 8 + 16;
u = (-38 * r - 74 * g + 112 * b + 128) >> 8 + 128;
v = (112 * r - 94 * g - 18 * b + 128) >> 8 + 128;
// clip y
yuv420sp[index++] = (byte) ((y < 0) ? 0 : ((y > 255) ? 255 : y));
U[index] = u;
V[index++] = v;
}
}
The problem is that encoding and decoding Yuv data might have some mistake because if i skip the preprocessing step than also encoded Yuv data are differ from original data of PreviewCallback.
Please help me to resolve this issue. I have to used this code in OCR scanning so i need to implement this type of logic.
If any other way of doing same thing than please provide me.
Thanks in advance. :)

Although the documentation suggests that you can set which format the image data should arrive from the camera in, in practice you often have a choice of one: NV21, a YUV format. For lots of information on this format see http://www.fourcc.org/yuv.php#NV21 and for information on the theory behind converting it to RGB see http://www.fourcc.org/fccyvrgb.php. There is a picture based explanation at Extract black and white image from android camera's NV21 format. There is an android specific section on a wikipedia page about the subject (thanks #AlexCohn): YUV#Y'UV420sp (NV21) to RGB conversion (Android).
However, once you've set up your onPreviewFrame routine, the mechanics of going from the byte array it sends you to useful data is somewhat, ummmm, unclear. From API 8 onwards, the following solution is available, to get to a ByteStream holiding a JPEG of the image (compressToJpeg is the only conversion option offered by YuvImage):
// pWidth and pHeight define the size of the preview Frame
ByteArrayOutputStream out = new ByteArrayOutputStream();
// Alter the second parameter of this to the actual format you are receiving
YuvImage yuv = new YuvImage(data, ImageFormat.NV21, pWidth, pHeight, null);
// bWidth and bHeight define the size of the bitmap you wish the fill with the preview image
yuv.compressToJpeg(new Rect(0, 0, bWidth, bHeight), 50, out);
This JPEG may then need to be converted into the format you want. If you want a Bitmap:
byte[] bytes = out.toByteArray();
Bitmap bitmap= BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
If, for whatever reason, you are unable to do this, you can do the conversion manually. Some problems to be overcome in doing this:
The data arrives in a byte array. By definition, bytes are signed numbers, meaning that they go from -128 to 127. However, the data is actually unsigned bytes (0 to 255). If this isn't dealt with, the outcome is doomed to have some odd clipping effects.
The data is in a very specific order (as per the previously mentioned web pages) and each pixel needs to be extracted carefully.
Each pixel needs to be put into the right place on a bitmap, say. This also requires a rather messy (in my view) approach of building a buffer of the data and then filling a bitmap from it.
In principle, the values should be stored [16..240], but it appears that they are stored [0..255] in the data sent to onPreviewFrame
Just about every web page on the matter proposes different coefficients, even allowing for [16..240] vs [0..255] options.
If you've actually got NV12 (another variant on YUV420), then you will need to swap the reads for U and V.
I present a solution (which seems to work), with requests for corrections, improvements and ways of making the whole thing less costly to run. I have set it out to hopefully make clear what is happening, rather than to optimise it for speed. It creates a bitmap the size of the preview image:
The data variable is coming from the call to onPreviewFrame
// Define whether expecting [16..240] or [0..255]
boolean dataIs16To240 = false;
// the bitmap we want to fill with the image
Bitmap bitmap = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ARGB_8888);
int numPixels = imageWidth*imageHeight;
// the buffer we fill up which we then fill the bitmap with
IntBuffer intBuffer = IntBuffer.allocate(imageWidth*imageHeight);
// If you're reusing a buffer, next line imperative to refill from the start,
// if not good practice
intBuffer.position(0);
// Set the alpha for the image: 0 is transparent, 255 fully opaque
final byte alpha = (byte) 255;
// Holding variables for the loop calculation
int R = 0;
int G = 0;
int B = 0;
// Get each pixel, one at a time
for (int y = 0; y < imageHeight; y++) {
for (int x = 0; x < imageWidth; x++) {
// Get the Y value, stored in the first block of data
// The logical "AND 0xff" is needed to deal with the signed issue
float Y = (float) (data[y*imageWidth + x] & 0xff);
// Get U and V values, stored after Y values, one per 2x2 block
// of pixels, interleaved. Prepare them as floats with correct range
// ready for calculation later.
int xby2 = x/2;
int yby2 = y/2;
// make this V for NV12/420SP
float U = (float)(data[numPixels + 2*xby2 + yby2*imageWidth] & 0xff) - 128.0f;
// make this U for NV12/420SP
float V = (float)(data[numPixels + 2*xby2 + 1 + yby2*imageWidth] & 0xff) - 128.0f;
if (dataIs16To240) {
// Correct Y to allow for the fact that it is [16..235] and not [0..255]
Y = 1.164*(Y - 16.0);
// Do the YUV -> RGB conversion
// These seem to work, but other variations are quoted
// out there.
R = (int)(Yf + 1.596f*V);
G = (int)(Yf - 0.813f*V - 0.391f*U);
B = (int)(Yf + 2.018f*U);
}
else {
// No need to correct Y
// These are the coefficients proposed by #AlexCohn
// for [0..255], as per the wikipedia page referenced
// above
R = (int)(Yf + 1.370705f*V);
G = (int)(Yf - 0.698001f*V - 0.337633f*U);
B = (int)(Yf + 1.732446f*U);
}
// Clip rgb values to 0-255
R = R < 0 ? 0 : R > 255 ? 255 : R;
G = G < 0 ? 0 : G > 255 ? 255 : G;
B = B < 0 ? 0 : B > 255 ? 255 : B;
// Put that pixel in the buffer
intBuffer.put(alpha*16777216 + R*65536 + G*256 + B);
}
}
// Get buffer ready to be read
intBuffer.flip();
// Push the pixel information from the buffer onto the bitmap.
bitmap.copyPixelsFromBuffer(intBuffer);
As #Timmmm points out below, you could do the conversion in int by multiplying the scaling factors by 1000 (ie. 1.164 becomes 1164) and then dividng the end results by 1000.

Why not specify that camera preview should provide RGB images?
i.e. Camera.Parameters.setPreviewFormat(ImageFormat.RGB_565);

You can use RenderScript -> ScriptIntrinsicYuvToRGB
Kotlin Sample
val rs = RenderScript.create(CONTEXT_HERE)
val yuvToRgbIntrinsic = ScriptIntrinsicYuvToRGB.create(rs, Element.U8_4(rs))
val yuvType = Type.Builder(rs, Element.U8(rs)).setX(byteArray.size)
val inData = Allocation.createTyped(rs, yuvType.create(), Allocation.USAGE_SCRIPT)
val rgbaType = Type.Builder(rs, Element.RGBA_8888(rs)).setX(width).setY(height)
val outData = Allocation.createTyped(rs, rgbaType.create(), Allocation.USAGE_SCRIPT)
inData.copyFrom(byteArray)
yuvToRgbIntrinsic.setInput(inData)
yuvToRgbIntrinsic.forEach(outData)
val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
outData.copyTo(bitmap)

After some tests on Samsung S4 mini fastest code is (120% faster then Neil's [floats!] and 30% faster then original Hitesh's):
static public void decodeYUV420SP(int[] rgba, byte[] yuv420sp, int width,
int height) {
final int frameSize = width * height;
// define variables before loops (+ 20-30% faster algorithm o0`)
int r, g, b, y1192, y, i, uvp, u, v;
for (int j = 0, yp = 0; j < height; j++) {
uvp = frameSize + (j >> 1) * width;
u = 0;
v = 0;
for (i = 0; i < width; i++, yp++) {
y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
y1192 = 1192 * y;
r = (y1192 + 1634 * v);
g = (y1192 - 833 * v - 400 * u);
b = (y1192 + 2066 * u);
// Java's functions are faster then 'IFs'
r = Math.max(0, Math.min(r, 262143));
g = Math.max(0, Math.min(g, 262143));
b = Math.max(0, Math.min(b, 262143));
// rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) &
// 0xff00) | ((b >> 10) & 0xff);
// rgba, divide 2^10 ( >> 10)
rgba[yp] = ((r << 14) & 0xff000000) | ((g << 6) & 0xff0000)
| ((b >> 2) | 0xff00);
}
}
}
Speed is comparable to YuvImage.compressToJpeg() with ByteArrayOutputStream as output (30-50 ms for 640x480 image).
Result: Samsung S4 mini (2x1.7GHz) can't compress to JPEG/convert YUV to RGB in real time (640x480#30fps)

Java implementation is 10 times slow than the c version, I suggest you use GPUImage library or just move this part of code.
There is a android version of GPUImage:
https://github.com/CyberAgent/android-gpuimage
You can include this library if you use gradle, and call the method:
GPUImageNativeLibrary.YUVtoRBGA( inputArray, WIDTH, HEIGHT, outputArray);
I compare the time, for a NV21 image which is 960x540, use above java code, it cost 200ms+, with GPUImage version, just 10ms~20ms.

You can use ColorHelper library for this:
using ColorHelper;
YUV yuv = new YUV(0.1, 0.1, 0.2);
RGB rgb = ColorConverter.YuvToRgb(yuv);
Links:
Github
Nuget

Fixup the above code snippet
static public void decodeYUV420SP(int[] rgba, byte[] yuv420sp, int width,
int height) {
final int frameSize = width * height;
int r, g, b, y1192, y, i, uvp, u, v;
for (int j = 0, yp = 0; j < height; j++) {
uvp = frameSize + (j >> 1) * width;
u = 0;
v = 0;
for (i = 0; i < width; i++, yp++) {
y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
// above answer is wrong at the following lines. just swap ***u*** and ***v***
u = (0xff & yuv420sp[uvp++]) - 128;
v = (0xff & yuv420sp[uvp++]) - 128;
}
y1192 = 1192 * y;
r = (y1192 + 1634 * v);
g = (y1192 - 833 * v - 400 * u);
b = (y1192 + 2066 * u);
r = Math.max(0, Math.min(r, 262143));
g = Math.max(0, Math.min(g, 262143));
b = Math.max(0, Math.min(b, 262143));
// combine ARGB
rgba[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00)
| ((b >> 10) | 0xff);
}
}
}

Try RenderScript ScriptIntrinsicYuvToRGB, which comes with JellyBean 4.2 (Api 17+).
https://developer.android.com/reference/android/renderscript/ScriptIntrinsicYuvToRGB.html
On Nexus 7 (2013, JellyBean 4.3) a 1920x1080 image conversion (full HD camera preview) takes about 7 ms.

You can get the bitmap directly from the TextureView. Which is really fast.
Bitmap bitmap = textureview.getBitmap()

After reading many suggested links, articles, etc. I found the following great Android example app which captures the YUV Image from the camera and converts it into RGB Bitmap:
https://github.com/android/camera-samples/tree/main/CameraXTfLite
Nice things about this:
It uses the aforementioned RenderScript framework and the code can be easily reused - check out the YuvToRgbConverter.kt class
according to their documentation, this code achieves " ~30 FPS # 640x480 on a Pixel 3 phone"
After switching to this code (especially the YUV to RGB conversion part) my framerate doubled! I am not quite reaching 30 FPS overall since I am doing a bit more things after capturing the image, but the speed-up is remarkable!

Android YUV Image format

In our application, we need to transfer video, we are using Camera class to capture the buffer and send to destination,
I have set format is YV12 as a Camera parameter to receive the buffer,
for the 500X300 buffer, we receive buffer of 230400 bytes,
i want to know , is this expected buffer size ?
I believe the size would be
Y Plane = width * height = 500X300 = 150000
U Plane = width/2 * height/2 = = 37500
V Plane = width/2 * height/2 = = 37500
========
225000
========
Can anyone explain me, if i need to get stride values of each component, how can i get that
Is there any way to get it ?

I can show you how you can get int rgb[] from this:
public int[] decodeYUV420SP(byte[] yuv420sp, int width, int height) {
final int frameSize = width * height;
int rgb[] = new int[width * height];
for (int j = 0, yp = 0; j < height; j++) {
int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
int y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
int y1192 = 1192 * y;
int r = (y1192 + 1634 * v);
int g = (y1192 - 833 * v - 400 * u);
int b = (y1192 + 2066 * u);
if (r < 0)
r = 0;
else if (r > 262143)
r = 262143;
if (g < 0)
g = 0;
else if (g > 262143)
g = 262143;
if (b < 0)
b = 0;
else if (b > 262143)
b = 262143;
rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000)
| ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
}
}
return rgb;
}

I guess Android document is already explained it:
http://developer.android.com/reference/android/graphics/ImageFormat.html#YV12

I think this is simple.
chekout YUVImage class from android. You can construct an YUV Image from byte[]data coming from camera preview.
You can write like this:
//width and height you get it from camera properties, image width and height of camera preview
YuvImage image=new YuvImage(data, ImageFormat.NV21, int width, int height, null);
byte[] newData = image.getYuvData();
//or if you want int format = image.getYuvFormat();

It's a quite old question, but I've struggled with the same issue for a few days. So I decided to write some comments to help others.
YV12 described in the Android developer site(here) seems not a kind of YV12 but IMC1. The page says that both of the y-stride and the uv-stride should be aligned in 16bytes.
And also this page says that:
For YV12, the image buffer that is received is not necessarily tightly
packed, as there may be padding at the end of each row of pixel data,
as described in YV12.
Based on the above comments, I calculated it using python command line:
>>> w = 500
>>> h = 300
>>> y_stride = (500 + 15) / 16 * 16.0
>>> y_stride
512.0
>>> y_size = y_stride * h
>>> y_size
153600.0
>>> uv_stride = (500 / 2 + 15) / 16 * 16.0
>>> uv_stride
256.0
>>> u_size = uv_stride * h / 2
>>> v_size = uv_stride * h / 2
>>> size = y_size + u_size + v_size
>>> size
230400.0