Billy responded:
> I keep trying to bring this back to what Vidiot asserted: that when you
>take a DVCAM recording you should remove setup for MPEG1/2. In both DV
>and in MPEG2, we deal with quantized Y'CbCr representations of the analog
>signal. It was always my understanding that a pure luminance signal at
>7.5 IRE would map to a quantized luminance value of 16, and any superblack
>signals would be in the 0-16 range.
Fatal flaw in your info. While the DV and MPEG standard has black at 16 and
white at 234. Setup black is at about 32. More below.
> Regardless, this data semantic of what the levels 'mean' is well defined
>in these digital specs. Any 'removal of setup' should be strictly in the
>hardware that takes this digital form and outputs it, or that captures it
>and provides me with a digital signal, and any MPEG2 file should use 16
>as its black level and 235 as its white level and know nothing about
>the letters I, R or E. :)
If only it were so. As I said in my posting, most consumer and pro-sumer
devices DO NOT remove NTSC setup when converting to DV. The 7.5 IRE black
level gets recorded at 32. It has to be done in software, otherwise the
setup level will get transferred to VCD and/or DVD recordings.
BTW, I thought the range was 16-234. In any event, 235 is close :-)
> So, how does this make any sense:
>
>> >> >> BTW, before going to VCD and/or DVD, the NTSC setup level needs
>> >> >> to be removed. So whatever tool you use, make sure that it can
>> >> >> remove NTSC setup, as the MPEG-1/2 standard does not use it and
>> >> >> leaving it in will cause problems.
See above.
MB
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