[libdv-dev] Re: Camcorder recommendation (FAQ?)

[Charles 'B. K. <kr...@cs...>]

Mads Bondo Dydensborg <ma...@ch...> writes:

> OK - that is nice. I forgot to mention that I live in a country
> where we use PAL. Is that a "problem" with the DV format? (Sorry if
> I appear clueless - it was easy to find information about IEEE 1394,
> but I have yet to find anything usefull about the DV format).

You will get a PAL DV camera if you buy it in Europe.  

The DV format defines separate PAL and NTSC modes.  The DV format is
different for each, which is good.  It does not attempt to find
"common denominator" that would necessisarily be sub-optimal for one
or both.  Lucky for you, PAL is better. ;-)  PAL DV is 720x576, where
NTSC is 720x480.

Actually, there are two PAL DV formats.  The original IEC standard,
and the newer smpte one.  The difference is in how color sampling is
done.  IEC DV does 4:2:0 for PAL.  SMPTE does 4:1:1 for PAL.  

From the software perspective, 4:2:0 is the best.  Only because it is
slightly easier to display on a computer.  The reason is that most
graphics cards support YUV overlays for 4:2:0 video (it's the same
that MPEG uses), and under Linux it is possible to take advantage of
that with the new Xv extension present in XFree86 4.0.x.

This makes a huge reduction in CPU requirements for software decoder.

Almost no video cards support YUV 4:1:1, and Xv doesn't support it at
all.  But YUV 4:2:2 is about as commonly supported as 4:2:0.  So we
can still take advantage of YUV but, we have to upsample from 4:1:1 to
4:2:2.

I am one of the authors of libdv, http://libdv.sourceforge.net, a
software DV decoder for Linux.  Libdv supports PAL (both kinds) and
NTSC.  

There are lots of sites with good information.  For Linux stuff 
check out Arne's:

  http://www.schirmacher.de/arne/dvgrab/index_e.html

-- Buck

> Thanks for all the information. I had not thought about the progressive
> scan thing at all. That is nice to know.

> The Sony models seems to be very nice, although a bit higher priced then
> jvc and panasonic, though.

> Mads