Wrong byte order for RGB565

[r-downing]

If I take a framebuffer from the camera in jpeg format, and pass it through jpg2rgb565(...), then back through fmt2jpg(...) the colors are all screwed up - the rgb channels seem to be swapped and shifted.

For context I was capturing high-res images, then passing them to the jpg2rgb... to scale them down and do some image processing.

But if I take the output buffer of jpg2rgb565(...) and swap every alternating byte before passing it back to fmt2jpg(...) then the image appears correct.

uint8_t rgbBuf[...];

jpg2rgb565(fb->buf, fb->len, rgbBuf, JPG_SCALE_8X);

// swap the byte order and the image looks ok
size_t i;
for(i = 0; i < sizeof(rgbBuf); i+=2){
    const uint8_t tmp = rgbBuf[i];
    rgbBuf[i] = rgbBuf[i+1];
    rgbBuf[i+1] = tmp;
}

fmt2jpg(rgbBuf, ...)

So I believe either the output of jpg2rgb565() or the expected input format of fmt2jpg(...) is wrong, but I'm not sure which. If you guys know, I can make a fix

[WangYuxin-esp]

Yes, my test here is the same as yours. The problem may be caused by the wrong byte order of the jpg2rgb565() function, because when the camera outputs data in standard RGB format, the fmt2jpg() function is normal.

[r-downing]

Ok, thanks for confirming! I'll make a PR tomorrow

…

On Wed, Jul 20, 2022, 11:33 PM yuxinwww ***@***.***> wrote: Yes, my test here is the same as yours. The problem may be caused by the wrong byte order of the jpg2rgb565() function, because when the camera outputs data in standard RGB format, the fmt2jpg() function is normal. — Reply to this email directly, view it on GitHub <#422 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGKJRO5AZWGFJR37H3S7MJLVVDAKJANCNFSM532W4Z3Q> . You are receiving this because you authored the thread.Message ID: ***@***.***>

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[AIWintermuteAI]

Bump.

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This issue appears to be stale. Please close it if its no longer valid.