On Tue, 22 Jun 2004, Trent Piepho wrote:
> On Tue, 22 Jun 2004, Steven M. Schultz wrote:
> > cards are "adequate". For archival purposes, well, quality isn't
> > free/cheap ;( The other gotcha is that the analog cards (at least
> > the Bt878 based ones) going thru the v4l layer yield square pixels
>
> You sure about that? I have no trouble setting my bt848 to capture at 720x480.
> This is since before v4l1 existed.
With 'xawtv'? That was the only thing I tried (a while back) and it
adamantly insisted that 640x480 was the max (and the data rate was
about 42GB/hr). I presume you're using a RAID-0 setup to handle the
fullframe 4:2:2 data (and then resampling to 4:2:0 later on).
But since moving away from the Bt cards a couple years ago I haven't
revisited to see if the situation's improved. At one time there
was the chroma bug where the chroma for the 2nd field was simply
replicated from the first field (when 4:2:0 capturing was being done,
the workaround was to capture in 4:2:2 and convert in software). All
in all I don't miss the beast at all.
Where in the configuration/setup menus is the choice if ITU-601 or
square pixels offered? The WinTV card is targeted at computer
playback/viewing and that would use square pixels...
I had the complete datasheets for the Bt848 but tossed 'em out not
too long ago - have to print 'em out again but I can't find in the
xawtv or kernel where the pixel aspect is passed thru and actually
set.
But if they're doing 720x480 then they're doing something wrong -
possibly capturing part of the blanking or whatever. Full
frame NTSC analog video is 704x480 10:11 or 640x480 1:1. That's
all the TV stations are putting out ...
DV has the extra 8 pixels on each side of a 704x480 frame but
Bt8x8 cards converting an analog signal shouldn't be giving out
720x480 unless the right and left 8 pixels are black and the center
704 are the actual data. I wouldn't be surprised if something is
padding/scaling things up a bit. One app I had (on another OS)
very carefully padded the 29.97... up to 30 :(
Cheers,
Steven Schultz
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