---
title: YUV to JPG Conversion
slug: smart-care/yuv-to-jpg-conversion
docTags: 
createdAt: 2025-06-03T07:32:23.342Z
---

| **Information** |                                                                                                                                                                                                                                    |
| --------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Description     | Code snippet for converting an Android ImageReader YUV frame to a JPG image.                                                                                                                                                       |
| Purpose         | The function:<br />* Converts raw YUV image data to an RGB Bitmap
* Scales it down to a predefined width (220 px) while maintaining aspect ratio
* Compresses the bitmap to JPEG (50% quality)
* Returns the result as a ByteArray |
| Language        | Kotlin                                                                                                                                                                                                                             |

### Input Parameters

- **yuvBytes**: `ByteArray`
  &#x20;The raw YUV NV21 frame data (e.g., from a camera preview).
- **width**: `Int`
  &#x20;Width of the image in pixels.
- **height**: `Int`
  &#x20;Height of the image in pixels.

### Output

- A `ByteArray` containing the compressed JPG image.

### Snippet

```kotlin
import com.google.android.renderscript.Toolkit
// ...

fun convertYuvToJpeg(
    yuvBytes: ByteArray,
    width: Int,
    height: Int,
    quality: Int = 50,
    desiredWidth: Int = 220
): ByteArray {
    val rgbBitmap = Toolkit.yuvToRgbBitmap(yuvBytes, width, height, YuvFormat.NV21).let {
        val bitmap = if (it.width > it.height) {
            val matrix = Matrix().apply { postRotate(-90f) }
            Bitmap.createBitmap(it, 0, 0, it.width, it.height, matrix, true)
        } else it

        val desiredHeight = desiredWidth * bitmap.height / bitmap.width
        Bitmap.createScaledBitmap(bitmap, desiredWidth, desiredHeight, false)
    }

    val outputStream = ByteArrayOutputStream()
    rgbBitmap.compress(Bitmap.CompressFormat.JPEG, quality, outputStream)
    return outputStream.toByteArray()
}
```

### Notes

- The JPG compression level (i.e. `quality`) is adjustable. A lower value reduces the file size at the cost of image quality. Use 50% as an initial value.
- The `desiredWidth` allows to configure the size of the JPG image. We have set this to 220px as a good compromise between file size and image resolution.
- The image transformation introduces a load on the system. It's recommended to run this in a separate thread to avoid blocking the main thread and causing frame-drop while recording.
- This snippet uses the `com.google.android.renderscript.Toolkit` dependency for the image conversion algorithm.