[mythtv-users] Picking a TV-out card (and a request for the group)

[David Wood]

First of all, I want to thank everyone again for so energetically helping
me investigate this problem. And it is certainly a problem - from what
I've seen, and there seems to be general agreement on this, you don't have
to be picky to think many graphics cards' TV-out is awful, and if you pick
one at random, you are likely to get screwed.

So, what kind of video card should you get?

First let me tell you: "I DON'T KNOW" - I didn't buy all the possible
cards in the world to survey them all and find out. Whatever I say here is
speculation. Some things more than others, and I try to point out my
bigger reaches, but all of it is guesswork. The point of sharing this is
to summarize what I've read so far, which may be helpful to other people
working on PVRs (and anything else that needs TV-out), but it may be
wrong, and if it is, DONT BLAME ME.  :D

Your best bet, as always, is to find someone else with a card they love,
and buy that _exact_ same card - and even then, you are not guaranteed to
get the same results.

One thing everyone agrees on is that the TV-out on the Hauppauge PVR-350
is good. _But_, the 350 is expensive, and the driver support is very iffy
at the moment. Maybe that's alright for some people - clearly there are
many for whom the current situation with the 350 is good enough. The speed
and stability limitations are subtle and constantly changing. But right
now (because I need to use MPEG4 codecs and hate drivers that are "in
active development") it won't work for me - I suspect for many others,
too.

That leads us to commodity video cards with S-video. And that leads us to
the perennial debate: ATI or nVidia. Looking around the net, I see that it
is reenacted everywhere, with added wrinkles about newer nVidia cards or
older, drivers, etc.

Unbeknownst to many people involved, a lot of this seems to come down to
what TV encoder chip is used on the card - and in some cases, even the
same make/model card can ship with many different ones! So, everyone is
telling the truth, but nobody can agree.  Some mx440 cards (for example)
will be great, others will be awful. I couldn't find much information
about ATI encoder chips (doesn't mean it's not out there) - but the
situation is similar there.

I'll start at the end. As far as I can tell, the nVidia cards are probably
best, _if you can get the right one_. I'll get into how to do that in a
minute.

By "best" I don't mean that there aren't other very good cards, including
cards from ATI. But:

1) Side-by-side tests run by philes seem to settle on good nVidia cards
as the winner on quality even in the close races (leaving aside the Matrox
G400, which won't even run on many new motherboards). For example, here's
an image comparison:

http://www.viperlair.com/reviews/video_graph/ati/radeon/9800xt/pg2.shtml

2) nVidia's driver situation is (for practical purposes) better on Linux.
With an nVidia card you can get 3D graphics _and_ good TV out performance
using their (closed source) drivers.

I found an excellent all-around hardware guide for PVR building (that is
windows-focused, but still quite useful). This covers all aspects of PVR
hardware in great detail and is current. I really wish I'd found it at the
start of my search instead of at the end...

http://htpcnews.com/forums/index.php?showtopic=1930

(also see: http://htpcnews.com/forums/index.php?showtopic=3749)

The important quote: "The newer GeForce 4MX (NV17) and GeForce FX series
cards have what many consider some of the best quality standard definition
TV output from a graphics card."

Backing up a bit, with respect to the much lauded nvidia GeForce4 mx440,
the person here who said they all use the same TV encoder chip and the
others who disagree are both right in a way. Well, not really, but, I can
see where the misunderstanding arises. Later mx440 cards ("NV17" and
"NV18") (and _apparently_ newer high-end cards - unconfirmed) appear to
have incorporated a TV encoder from nVidia, rather than using 3rd party
chips, and this encoder is apparently _good_.

However, not even all mx440 cards do this. Bleah.

So, if you want to buy an nvidia card (especially a _cheap_ nvidia card),
and not get screwed, what do you buy?

Unfortunately (at least at the moment) to find out, you have to do some
work, and take at least a tiny bit of risk. But by using the resources
available to us, it seems we can really tip the odds in our favor.

*** One thing I really want to encourage is for nVidia users who have
TV-out performance they're really happy with to grep their XFree86 logs
for lines that have "TV" in them and report the TV encoder chip that the X
server detects, along with the make/model of the card and (preferably)
where they bought it. I think this will actually help a lot of people.

In the meantime, absenting such a list, we can do a little detective work.
Here's an out-of-date summary of 3rd party nVidia TV-encoder chips.

http://tvtool.info/index_e.htm

It concludes that Brooktree/Conexant 871/872 encoders are (were) the top
of the heap - this jibes with what I see from a PNY GeForce4 ti4400 I
have, which (as XFree confirms) has the Brooktree 871 chip and is quite
good.

Now, since this summary was written, it appears Conexant has expanded the
product line, and 871/872/873/874/875 chips are part of the same family,
basically pin-compatible, and, I speculate (!), all of relatively high
quality.  I am even less certain about the BT868/869 chips, but absenting
first hand reports, they're preferable to a chip you know is bad, like the
SAA7102.

In addition, we have the new NV17/NV18 encoders, which are supposed to be
excellent, and then whatever is on the newer (i.e. FX) cards, which I have
not enough information about to draw a good conclusion (but for which
reviews are generally favorable).

If you want to go with a high-end nVidia card for TV-out, you may be in
good shape, but be careful and make sure your store has a good return
policy. But from here on out let's talk about budget cards (i.e. $30-40) -
probably the mx440, but other, older cards with good tv chips are in play
too.

This is an (old-ish) list of encoder chips in nvidia cards:

http://tvtool.info/index_e.htm

>From these two things we can start to figure out what makes and models of
cards are a good bet. On the downside, we can see that, on many cards,
some of the possible chips you'll get are stinkers.  So what we want to
look for are vendors and models that, even if they vary, at least have a
consistent (or nearly consistent) pattern of quality - especially the
NV17/18, but at least CX2587*. In addition, I can pass along a general
admonition against getting "SE" ("special edition") cards, which are
reputed to be of inferior quality.

In looking through the list so far, I deduce Chaintech, PNY and MSI mx440
cards are good bets.

Comments?