将专用NV12视频帧转换为RGB

Question

I have an H264 stream that's decoded using an Android MediaCodec. When I query the output MediaFormat, the color format is 2141391875. Apparently, that's a specialized NV12 variant known as HAL_PIXEL_FORMAT_NV12_ADRENO_TILED. This is on a Nexus 7 (2013).

I want to take this data and convert it to RGB so I can create a Bitmap. I've found StackOverflow posts for converting other formats to RGB, not this format. I've tried code from those other posts, the result is just streaks of color. (To view the Bitmap, I draw on the Canvas associated with a Surface, as well as write it out as a JPEG -- it looks the same in both cases.)

How can I convert this particular data to RGB?

Answer 1

2141391875 decimal is 0x7FA30C03 in hex, which according to this header file is OMX_QCOM_COLOR_FormatYUV420PackedSemiPlanar64x32Tile2m8ka . Which amounts to the same thing as the constant you found: this is a proprietary Qualcomm color format.

The easiest (and fastest) way to convert it is to let OpenGL ES do the work for you. See for example ExtractMpegFramesTest , which decodes video frames to a SurfaceTexture, renders the texture to an off-screen surface, and then reads the pixels out with glReadPixels() . The GLES driver will handle the RGB conversion for you.

If you want to do the conversion yourself, you will need to reverse-engineer the color format, or find someone who has done so already and is willing to share.