CODEWITHSUNDEEP
androidbitmaprgbandroid-mediacodec
Paul Steckler
Paul Steckler

Reputation: 627

Converting specialized NV12 video frames to RGB

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?

Upvotes: 3

Views: 2256

Answers (1)

fadden
fadden

Reputation: 52313

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.

Upvotes: 1

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