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ADV7842 HDMI input colour space detection

Question asked by adhawkins on Jun 5, 2013
Latest reply on Jun 7, 2013 by adhawkins

Hi,

 

We are setting up the HDMI inputs such that the input colour space is automatically determined (by writing 1111 to INP_COLOR_SPACE). We have OP_656_RANGE set to force a limited range on the output.

 

If we put in a YUV signal to the HDMI input, it appears that it is incorrectly deciding that this is a limited range input signal, despite table 48 of the hardware guide (page 281 or our PDF) saying that the input range is always 0:255 for YUV. If we manually set this (by setting INP_COLOR_SPACE to 0111), then the output is scaled correctly. (We can see this by feeding in a grey scale image containing 8 grey levels. The top and bottom step sizes are smaller than all the rest, indicating that these are being clipped rather than scaled).

 

Am I misinterpreting table 48? Or is the 7842 behaving incorrectly in this case?

 

Thanks

 

Andy

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