Nexus 9 Camera2 API - YUV_420_888 vs. getOutputSiz

问题:

I'm implementing the Camera2 API with the YUV_420_888 format on a Nexus 9. I checked the output sizes and wanted to use the largest (8MP, 3280 x 2460) size to save. However, it just appears as static lines, similar to how old TV's looked without a signal. I would like to stick with YUV_420_888 since my end goal is to save grayscale data (Y component).

I originally thought it was a camera bandwidth issue, but the same thing happened at some of the small sizes (320 x 240). None of the problems went away even when I increased frame duration and decreased the size of the preview to save on bandwidth. Some of the other sizes DID work (2048 x 1536, 1280 x 720) but I did not check all of them.

I'm starting to think getOutputSizes() may not necessarily be accurate. It gave me the same results for all other formats except RAW_SENSOR (JPEG, YUV_420_888, YV12). Has anyone encountered this or determined a solution?

回答1:

Figured out the issue. I was not taking into account the rowStride of the returned pixels. So I had to run a for-loop to extract the non-padded data before saving it:

myRowStride = mImage.getPlanes()[0].getRowStride();
int iSkippedBytes = 0;
for (int i = 0; i < mStillSize.getWidth() * mStillSize.getHeight(); i++){
    if (i % mStillSize.getWidth() == 0 && i != 0)
          iSkippedBytes = iSkippedBytes + (myRowStride - mStillSize.getWidth());
    imageBytes[i] = bytes[i + iSkippedBytes];
 }