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Save Alby-o/fe87e35bc21d534c8220aed7df028e03 to your computer and use it in GitHub Desktop.
// imgLib -> Image package from https://pub.dartlang.org/packages/image | |
import 'package:image/image.dart' as imglib; | |
import 'package:camera/camera.dart'; | |
Future<List<int>> convertImagetoPng(CameraImage image) async { | |
try { | |
imglib.Image img; | |
if (image.format.group == ImageFormatGroup.yuv420) { | |
img = _convertYUV420(image); | |
} else if (image.format.group == ImageFormatGroup.bgra8888) { | |
img = _convertBGRA8888(image); | |
} | |
imglib.PngEncoder pngEncoder = new imglib.PngEncoder(); | |
// Convert to png | |
List<int> png = pngEncoder.encodeImage(img); | |
return png; | |
} catch (e) { | |
print(">>>>>>>>>>>> ERROR:" + e.toString()); | |
} | |
return null; | |
} | |
// CameraImage BGRA8888 -> PNG | |
// Color | |
imglib.Image _convertBGRA8888(CameraImage image) { | |
return imglib.Image.fromBytes( | |
image.width, | |
image.height, | |
image.planes[0].bytes, | |
format: imglib.Format.bgra, | |
); | |
} | |
// CameraImage YUV420_888 -> PNG -> Image (compresion:0, filter: none) | |
// Black | |
imglib.Image _convertYUV420(CameraImage image) { | |
var img = imglib.Image(image.width, image.height); // Create Image buffer | |
Plane plane = image.planes[0]; | |
const int shift = (0xFF << 24); | |
// Fill image buffer with plane[0] from YUV420_888 | |
for (int x = 0; x < image.width; x++) { | |
for (int planeOffset = 0; | |
planeOffset < image.height * image.width; | |
planeOffset += image.width) { | |
final pixelColor = plane.bytes[planeOffset + x]; | |
// color: 0x FF FF FF FF | |
// A B G R | |
// Calculate pixel color | |
var newVal = shift | (pixelColor << 16) | (pixelColor << 8) | pixelColor; | |
img.data[planeOffset + x] = newVal; | |
} | |
} | |
return img; | |
} |
About a few days of struggling with the CamerImage to Image conversion, I managed to improve the method to include paddnig on different devices. I tested on several devices, checking the conversion at different camera resolutions. And I think it works.
imglib.Image convertYUV420ToImage(CameraImage cameraImage) {
final imageWidth = cameraImage.width;
final imageHeight = cameraImage.height;
final yBuffer = cameraImage.planes[0].bytes;
final uBuffer = cameraImage.planes[1].bytes;
final vBuffer = cameraImage.planes[2].bytes;
final int yRowStride = cameraImage.planes[0].bytesPerRow;
final int yPixelStride = cameraImage.planes[0].bytesPerPixel!;
final int uvRowStride = cameraImage.planes[1].bytesPerRow;
final int uvPixelStride = cameraImage.planes[1].bytesPerPixel!;
final image = imglib.Image(imageWidth, imageHeight);
for (int h = 0; h < imageHeight; h++) {
int uvh = (h / 2).floor();
for (int w = 0; w < imageWidth; w++) {
int uvw = (w / 2).floor();
final yIndex = (h * yRowStride) + (w * yPixelStride);
// Y plane should have positive values belonging to [0...255]
final int y = yBuffer[yIndex];
// U/V Values are subsampled i.e. each pixel in U/V chanel in a
// YUV_420 image act as chroma value for 4 neighbouring pixels
final int uvIndex = (uvh * uvRowStride) + (uvw * uvPixelStride);
// U/V values ideally fall under [-0.5, 0.5] range. To fit them into
// [0, 255] range they are scaled up and centered to 128.
// Operation below brings U/V values to [-128, 127].
final int u = uBuffer[uvIndex];
final int v = vBuffer[uvIndex];
// Compute RGB values per formula above.
int r = (y + v * 1436 / 1024 - 179).round();
int g = (y - u * 46549 / 131072 + 44 - v * 93604 / 131072 + 91).round();
int b = (y + u * 1814 / 1024 - 227).round();
r = r.clamp(0, 255);
g = g.clamp(0, 255);
b = b.clamp(0, 255);
// Use 255 for alpha value, no transparency. ARGB values are
// positioned in each byte of a single 4 byte integer
// [AAAAAAAARRRRRRRRGGGGGGGGBBBBBBBB]
final int argbIndex = h * imageWidth + w;
image.data[argbIndex] = 0xff000000 |
((b << 16) & 0xff0000) |
((g << 8) & 0xff00) |
(r & 0xff);
}
}
return image;
}
This code has some deprecated classes for Flutter 3.7.1:
imglib.Image _convertBGRA8888(CameraImage image)
has to be rewritten because of imglib.Image.fromBytes
doesn't accept direct parameters and the Format enum doesn't have the bgra value.
imglib.Image _convertBGRA8888(CameraImage image) {
return imglib.Image.fromBytes(
image.width,
image.height,
image.planes[0].bytes,
order: ChannelOrder.bgra,
);
}
Hi, 'img.data[index]' seems no longer use, how to modify the code when using convertYUV420ToImage?
Hi, 'img.data[index]' seems no longer use, how to modify the code when using convertYUV420ToImage?
I have the same problem
Hi, 'img.data[index]' seems no longer use, how to modify the code when using convertYUV420ToImage?
I have the same problem
Hi juanlabrador
I found a way and it's work well. Replace 'img.data[index]' to 'img.setPixelRgba(x, y, r, g, b, hexFF);'
Hi, 'img.data[index]' seems no longer use, how to modify the code when using convertYUV420ToImage?
I have the same problem
Hi juanlabrador
I found a way and it's work well. Replace 'img.data[index]' to 'img.setPixelRgba(x, y, r, g, b, hexFF);'
And what should go into each value?
imglib.Image _convertBGRA8888(CameraImage image) { return imglib.Image.fromBytes( image.width, image.height, image.planes[0].bytes, order: ChannelOrder.bgra, ); }
the image result is all broken.
@neoacevedo I used this function.
static imglib.Image convertBGRA8888ToImage(CameraImage cameraImage) {
return imglib.Image.fromBytes(
width: cameraImage.planes[0].width!,
height: cameraImage.planes[0].height!,
bytes: cameraImage.planes[0].bytes.buffer,
order: imglib.ChannelOrder.bgra,
);
}
I used this function.
static imglib.Image convertBGRA8888ToImage(CameraImage cameraImage) {
return imglib.Image.fromBytes(
width: cameraImage.planes[0].width!,
height: cameraImage.planes[0].height!,
bytes: cameraImage.planes[0].bytes.buffer,
order: imglib.ChannelOrder.bgra,
);
}
its working for iOS, but not on Android.
What imageFormatGroup did you use to create the Camera Controller?
federico-amura-kenility I think on Android you should use convertYUV420ToImage. I modify my class after update Image lib, please try this code.
part of object_detection;
/// ImageUtils
class ImageUtils {
///
/// Converts a [CameraImage] in YUV420 format to [image_lib.Image] in RGB format
///
static imglib.Image convertCameraImage(CameraImage cameraImage) {
if (cameraImage.format.group == ImageFormatGroup.yuv420) {
return convertYUV420ToImage(cameraImage);
} else if (cameraImage.format.group == ImageFormatGroup.bgra8888) {
return convertBGRA8888ToImage(cameraImage);
} else {
throw Exception('Undefined image type.');
}
}
///
/// Converts a [CameraImage] in BGRA888 format to [image_lib.Image] in RGB format
///
static imglib.Image convertBGRA8888ToImage(CameraImage cameraImage) {
return imglib.Image.fromBytes(
width: cameraImage.planes[0].width!,
height: cameraImage.planes[0].height!,
bytes: cameraImage.planes[0].bytes.buffer,
order: imglib.ChannelOrder.bgra,
);
}
///
/// Converts a [CameraImage] in YUV420 format to [image_lib.Image] in RGB format
///
static imglib.Image convertYUV420ToImage(CameraImage cameraImage) {
final imageWidth = cameraImage.width;
final imageHeight = cameraImage.height;
final yBuffer = cameraImage.planes[0].bytes;
final uBuffer = cameraImage.planes[1].bytes;
final vBuffer = cameraImage.planes[2].bytes;
final int yRowStride = cameraImage.planes[0].bytesPerRow;
final int yPixelStride = cameraImage.planes[0].bytesPerPixel!;
final int uvRowStride = cameraImage.planes[1].bytesPerRow;
final int uvPixelStride = cameraImage.planes[1].bytesPerPixel!;
final image = imglib.Image(width: imageWidth, height: imageHeight);
for (int h = 0; h < imageHeight; h++) {
int uvh = (h / 2).floor();
for (int w = 0; w < imageWidth; w++) {
int uvw = (w / 2).floor();
final yIndex = (h * yRowStride) + (w * yPixelStride);
// Y plane should have positive values belonging to [0...255]
final int y = yBuffer[yIndex];
// U/V Values are subsampled i.e. each pixel in U/V chanel in a
// YUV_420 image act as chroma value for 4 neighbouring pixels
final int uvIndex = (uvh * uvRowStride) + (uvw * uvPixelStride);
// U/V values ideally fall under [-0.5, 0.5] range. To fit them into
// [0, 255] range they are scaled up and centered to 128.
// Operation below brings U/V values to [-128, 127].
final int u = uBuffer[uvIndex];
final int v = vBuffer[uvIndex];
// Compute RGB values per formula above.
int r = (y + v * 1436 / 1024 - 179).round();
int g = (y - u * 46549 / 131072 + 44 - v * 93604 / 131072 + 91).round();
int b = (y + u * 1814 / 1024 - 227).round();
r = r.clamp(0, 255);
g = g.clamp(0, 255);
b = b.clamp(0, 255);
image.setPixelRgb(w, h, r, g, b);
}
}
return image;
}
}
After some trial and error, I found the perfect solution for iOS:
const IOS_BYTES_OFFSET = 28;
static Image _convertBGRA8888ToImage(CameraImage cameraImage) {
final plane = cameraImage.planes[0];
return Image.fromBytes(
width: cameraImage.width,
height: cameraImage.height,
bytes: plane.bytes.buffer,
rowStride: plane.bytesPerRow,
bytesOffset: IOS_BYTES_OFFSET,
order: ChannelOrder.bgra,
);
}
The other solution produced a 1088 wide image with a 8px black bar. By adding rowStride
and bytesOffset
, it is now 1080 width with no black bars.
I have no idea where the offset of 28 comes from. Does anyone know why 28 works?
@saad-palapa Does anyone know why 28 works?
Now that we know the answer, the explanation is rather easy. 28 bytes is 8 pixels of BGRA. The image in memory is 1088 pixel wide with a black bar before the first column (the illustration keeps the 8 "black" extra pixels, but does not go keep the real dimensions):
XXXXXXXX......................
XXXXXXXX.......... _ .........
XXXXXXXX........ _( )_ .......
XXXXXXXX....... (_(%)_) ......
XXXXXXXX......... (_)\ .......
XXXXXXXX............. | __ ...
XXXXXXXX............. |/_/ ...
XXXXXXXX............. | ......
XXXXXXXX............. | ......
XXXXXXXX......................
XXXXXXXX......................
By adding the offset, you feed to Image.fromBytes()
something like
......................XXXXXXXX
.......... _ .........XXXXXXXX
........ _( )_ .......XXXXXXXX
....... (_(%)_) ......XXXXXXXX
......... (_)\ .......XXXXXXXX
............. | __ ...XXXXXXXX
............. |/_/ ...XXXXXXXX
............. | ......XXXXXXXX
............. | ......XXXXXXXX
......................XXXXXXXX
......................
The function is smart enough to throw away the extra pixels on the right when the width
parameter is 1080 and rowStride
is 1088.
Hello, I meet another problem. Does anyone try to convert NV21 from cameraImage to image ?
Some device (Xiaomi, Motorola) will have the NV21 format. Anyone can help?
@rraayy you can see how this can be efficiently done with ffi on medium. The sample code is available at https://github.com/Hugand/camera_tutorial
@rraayy you can see how this can be efficiently done with ffi on medium. The sample code is available at https://github.com/Hugand/camera_tutorial
Thanks so much @alexcohn , I will try it with ffi!
federico-amura-kenility I think on Android you should use convertYUV420ToImage. I modify my class after update Image lib, please try this code.
This works on Android, thank you very much.
@rraayy Any luck converting NV21 to Image? I'm having the same difficulties. The NV21 formatted CameraImage object only has one plane.
@owjoh here @camsim99 claims that the issue with NV21 for Motorola and Xiaomi has been fixed in a recent CameraX implementation.
Alternatively, convertImage function could be tuned to handle single-plane images, but I don't know their actual layout.
can anyone help me with yuv420 to RGB conversion on iOS ?
About a few days of struggling with the CamerImage to Image conversion, I managed to improve the method to include paddnig on different devices. I tested on several devices, checking the conversion at different camera resolutions. And I think it works.
imglib.Image convertYUV420ToImage(CameraImage cameraImage) { final imageWidth = cameraImage.width; final imageHeight = cameraImage.height; final yBuffer = cameraImage.planes[0].bytes; final uBuffer = cameraImage.planes[1].bytes; final vBuffer = cameraImage.planes[2].bytes; final int yRowStride = cameraImage.planes[0].bytesPerRow; final int yPixelStride = cameraImage.planes[0].bytesPerPixel!; final int uvRowStride = cameraImage.planes[1].bytesPerRow; final int uvPixelStride = cameraImage.planes[1].bytesPerPixel!; final image = imglib.Image(imageWidth, imageHeight); for (int h = 0; h < imageHeight; h++) { int uvh = (h / 2).floor(); for (int w = 0; w < imageWidth; w++) { int uvw = (w / 2).floor(); final yIndex = (h * yRowStride) + (w * yPixelStride); // Y plane should have positive values belonging to [0...255] final int y = yBuffer[yIndex]; // U/V Values are subsampled i.e. each pixel in U/V chanel in a // YUV_420 image act as chroma value for 4 neighbouring pixels final int uvIndex = (uvh * uvRowStride) + (uvw * uvPixelStride); // U/V values ideally fall under [-0.5, 0.5] range. To fit them into // [0, 255] range they are scaled up and centered to 128. // Operation below brings U/V values to [-128, 127]. final int u = uBuffer[uvIndex]; final int v = vBuffer[uvIndex]; // Compute RGB values per formula above. int r = (y + v * 1436 / 1024 - 179).round(); int g = (y - u * 46549 / 131072 + 44 - v * 93604 / 131072 + 91).round(); int b = (y + u * 1814 / 1024 - 227).round(); r = r.clamp(0, 255); g = g.clamp(0, 255); b = b.clamp(0, 255); // Use 255 for alpha value, no transparency. ARGB values are // positioned in each byte of a single 4 byte integer // [AAAAAAAARRRRRRRRGGGGGGGGBBBBBBBB] final int argbIndex = h * imageWidth + w; image.data[argbIndex] = 0xff000000 | ((b << 16) & 0xff0000) | ((g << 8) & 0xff00) | (r & 0xff); } } return image; }
Does this work for iOS ?
Hi @prkhrv,
Please take a look at nv21 to Image
In my project, the solution is work for me.
i fix it with use image.setPixelRgb it got valid image
by
"
imglib.Image convertYUV420ToImage(CameraImage cameraImage) {
final imageWidth = cameraImage.width;
final imageHeight = cameraImage.height;
final yBuffer = cameraImage.planes[0].bytes;
final uBuffer = cameraImage.planes[1].bytes;
final vBuffer = cameraImage.planes[2].bytes;
final int yRowStride = cameraImage.planes[0].bytesPerRow;
final int yPixelStride = cameraImage.planes[0].bytesPerPixel!;
final int uvRowStride = cameraImage.planes[1].bytesPerRow;
final int uvPixelStride = cameraImage.planes[1].bytesPerPixel!;
final image = imglib.Image(width: imageWidth, height: imageHeight);
for (int h = 0; h < imageHeight; h++) {
int uvh = (h / 2).floor();
for (int w = 0; w < imageWidth; w++) {
int uvw = (w / 2).floor();
final yIndex = (h * yRowStride) + (w * yPixelStride);
// Y plane should have positive values belonging to [0...255]
final int y = yBuffer[yIndex];
// U/V Values are subsampled i.e. each pixel in U/V chanel in a
// YUV_420 image act as chroma value for 4 neighbouring pixels
final int uvIndex = (uvh * uvRowStride) + (uvw * uvPixelStride);
// U/V values ideally fall under [-0.5, 0.5] range. To fit them into
// [0, 255] range they are scaled up and centered to 128.
// Operation below brings U/V values to [-128, 127].
final int u = uBuffer[uvIndex];
final int v = vBuffer[uvIndex];
// Compute RGB values per formula above.
int r = (y + v * 1436 / 1024 - 179).round();
int g = (y - u * 46549 / 131072 + 44 - v * 93604 / 131072 + 91).round();
int b = (y + u * 1814 / 1024 - 227).round();
r = r.clamp(0, 255);
g = g.clamp(0, 255);
b = b.clamp(0, 255);
// Use 255 for alpha value, no transparency.
image.setPixelRgb(w, h, r, g, b);
}
}
return image;
}
"
but it still rotate the image by 270 degrees
you can fix it by rotate but i don't know how to to i just rotate in python backend !
imglib.Image _convertYUV420(CameraImage image) { var img = imglib.Image(image.width, image.height); // Create Image buffer final int width = image.width; final int height = image.height; final int uvRowStride = image.planes[1].bytesPerRow; final int uvPixelStride = image.planes[1].bytesPerPixel; const shift = (0xFF << 24); for(int x=0; x < width; x++) { for(int y=0; y < height; y++) { final int uvIndex = uvPixelStride * (x/2).floor() + uvRowStride*(y/2).floor(); final int index = y * width + x; final yp = image.planes[0].bytes[index]; final up = image.planes[1].bytes[uvIndex]; final vp = image.planes[2].bytes[uvIndex]; // Calculate pixel color int r = (yp + vp * 1436 / 1024 - 179).round().clamp(0, 255); int g = (yp - up * 46549 / 131072 + 44 -vp * 93604 / 131072 + 91).round().clamp(0, 255); int b = (yp + up * 1814 / 1024 - 227).round().clamp(0, 255); // color: 0x FF FF FF FF // A B G R img.data[index] = shift | (b << 16) | (g << 8) | r; } } return img; }@sikandernoori this way, it can be converted into color images, but it takes more than 1000ms to convert on a mobile phone with Snapdragon 870 CPU, and it will block the UI.
This works with 2 planes like the iPad camera does. But for me, "final int uvPixelStride = image.planes[1].bytesPerPixel;" is always null, so I cannot use this code. Any Idea what I can change if that is null?
@KevinCCucumber what device are you working with?
@KevinCCucumber what device are you working with?
@alexcohn I am using an ipad air 5th gen
@KevinCCucumber what does it report on ipad air 5th gen for image.planes[0].bytesPerPixel
? image.planes[1].bytesPerRow
?
Hi, is there any update here ? The new version of image library is working differently
Thanks for your answers, I see many kinds of solutions.
I now want to convert yuv420 images to color, can you tell me which solution can do it?
I've seen many that only convert to black and white, and that's not what I want.
In addition, the camera's imageFormatGroup parameter is set to jpeg, you can easily convert the color image, but I found that it will cause the preview screen lag, the experience is very bad.
So I may only be able to convert yuv420.
Thank you very much!