Convert android.media.Image (YUV_420_888) to Bitma

问题:

I'm trying to implement camera preview image data processing using camera2 api as proposed here: Camera preview image data processing with Android L and Camera2 API.

I successfully receive callbacks using onImageAvailableListener, but for future processing I need to obtain bitmap from YUV_420_888 android.media.Image. I searched for similar questions, but none of them helped.

Could you please suggest me how to convert android.media.Image (YUV_420_888) to Bitmap or maybe there's a better way of listening for preview frames?

回答1:

I write some code about this, and it's the YUV datas preview and chang it to JPEG datas ,and I can use it to save as bitmap ,byte[] ,or others.(You can see the class "Allocation" ).

And SDK document says:
"For efficient YUV processing with android.renderscript: Create a RenderScript Allocation with a supported YUV type, the IO_INPUT flag, and one of the sizes returned by getOutputSizes(Allocation.class), Then obtain the Surface with getSurface()."

here is the code, hope it will help you:https://github.com/pinguo-yuyidong/Camera2/blob/master/camera2/src/main/rs/yuv2rgb.rs

回答2:

For a simpler solution see my implementation here:

Conversion YUV 420_888 to Bitmap (full code)

The function takes the media.image as input, and creates three RenderScript allocations based on the y-, u- and v-planes. It follows the YUV_420_888 logic as shown in this Wikipedia illustration.

However, here we have three separate image planes for the Y, U and V-channels, thus I take these as three byte[], i.e. U8 allocations. The y-allocation has size width * height bytes, while the u- and v-allocatons have size width * height/4 bytes each, reflecting the fact that each u-byte covers 4 pixels (ditto each v byte).