Fix display of jpeg with luminance subsampling (for instance, if MCU …

[alggm]

…is Y=1x1, Cb=2x2, Cr=2x2).

Missing offset inside the MCU for the chroma components. For isntance, for the case where MCU is Y=1x1, Cb=2x2, Cr=2x2, the four 8x8 chrominance blocks ended up being written at the same location, thus most of the picture appeared in grayscale.

[ImpulseAdventure]

Excellent... thanks for identifying this! Do you have an example with luminance subsampling that you can attach to this issue? thx

[alggm]

Please find below a testcase with the suggested subsampling: You should observe the below difference after/before the fix: That is a random picture from Google ; I am not a red onion fanatic. Or maybe I am.

[alggm]

Do you need any more information @ImpulseAdventure ?

[ImpulseAdventure]

Thank you very much for providing the sample and associated fix!