quietvoid wrote: Tue Dec 22, 2020 10:49 pm
420 is not wrong, the patent specs also only mention 12 bit YCbCr 420 reconstructed output.
As for the HDMI transmission, it is detailed as 12 bit YCbCr 422
because the metadata is also transported into the least significant bits.
first off, nobody said 420 is "wrong" - that is your wording. 420 simply has less color resolution, hence 422 is more desirable.
Second, both STD and LLDV output a 12bit 422 signal
yet only STD contains in addition the dynamic metadata because it's tv-led. so the player-led stream (already DV decoded) which also contains 12bit 422 signal requires
less bandwidth, hence it provides low latency...
again,
BOTH DV stream types contain 12bit 422 signal (because that's the Dolby spec), yet LLDV has less data than the other... only STD carries metadata in the stream, not LLDV.... hence your 2nd statement is also wrong.
to recap:
all DV streams are 12 bit 422.
only tv-led contains the full dynamic metadata, so full stream requirements, hence RGB tunneling in 8bit float container is used.
player-led requires less bandwidth because it contains less data (still 12 bit 422 signal).
MEL is also 12 bit 422 but only contains a 10bit 420 signal, padded.
and to stress this part:
quietvoid wrote: Tue Dec 22, 2020 10:49 pm
because the metadata is also transported into the least significant bits.
you make it sound like that "explains" a 12bit 420 final output. no, the metadata allows to reconstruct the full 12bit 422 master, which is why it is a 12bit 422 signal.
if final output was 12bit 420 (so EL only contains luminance, Y difference) for FEL STD, they wouldn't need a 12 bit 422 stream, they'd use a 12bit 420 stream. Metadata is the mere difference, it doesn't need "extra" space on top of the difference, especially since it's encoded as well.
. Thanks for your feedback.
