Avermedia 507 TV

[Danny Pansters]

On Thursday 17 April 2008 13:31:50 Da Rock wrote:

<snip>

> You'll have to excuse me presumption here (I'll normally read all
> messages before adding to a thread), but you sound like a very good
> source of info here. May I ask you if you can supply some references to
> what you're posting here? I'd like to investigate this much further...

Principal source I used for the current tuner support with saa:

"FQ1200MK3 application note" from Philips (google).

The bandswitch commands for the different types come from the original saa 
example code (which I found didn't work properly for mk3 tuners until I added 
more initialization). Also, in the kbtv2 tarball, in drivers/saa/saa.h there 
are quite extensive comments.

There are plenty (semi-)technical datasheets you can find online, but 
documents such as "application notes" seem to be hard to get by.

There are two things, with tuners and any other hardware chip or component 
really: one is you need to understand how they work and what certain 
words/lingo mean (an electrical circuit schema can in principle be enough), 
two is there will always be a certain specific way (registers) to pass and 
retrieve and possibly convert the data you send/receive from the programmable 
parts of the circuity, even if two tuner types essentially use the exact same 
physics.

Contrary to popular belief, the problem with HW support in OSS is the latter 
more often than the former I think. That's not to say that the first isn't a 
hurdle. ATM I find myself studying PLLs more closely with the expectation 
that eventually I can understand a specific configuration more easily and 
possibly guess to some extend how HW registers are organized. I'd like to 
reorganize the tuner support that's now in the saa backend so that this 
becomes one type/class while adding other types, such as the newer silicon 
tuners (microtune, xceive, fujitsu).

I have some pdfs I could send you but there's no one definitive guide to a 
very broad area like this. And I wouldn't say that I have a broad enough view 
here to act as a trusty guide frankly.

If you're mostly interested in (digital) video I can recommend "Video 
demystified" by Keith Jack. Pretty hard core but stuffed with all sorts of 
useful info.

> Also, I thought I read somewhere that firmware is used in most tuners.
> Plus I found the linux drivers use firmware to make this work. Just a
> thought.

Well firmware can and is used for more than tuner support, also for example 
for a/v decoding (not to be confused with mpeg encoding) with the cxm driver, 
i.e. hauppauge PVR-150, i.e. pvrxxx). Tuning is just one thing that could be 
in a firmware. There's a firmware kernel module, used with cxm, that can load 
firmware. Essentially firmware is a blob that runs in your kernel.

So, if not needed, I prefer to avoid it, especially with saa, because the a/v 
stuff is all OSS and BSD licensed and it works alright.

There's another thing which may be confused with firmware, and that's eeprom. 
Tuners tend to have an eeprom that can be read to identify itself (eeproms 
don't execute code), and while they may be useful for identifying tuners 
they're also often busted or produce nonsense or disinformation. If you don't 
need to depend on an eeprom, I'd say avoid it.

All IMHO of course -- I'm just self-taught here. I once wanted to just make a 
nice tv viewer for bktr. Then I got an avermedia card for 20 euro... then 
stole a webcam (lately it has been stolen back though, but it lasted long 
enough to support it in kbtv), and honestly bought a pvr150 card :) And then 
there's this eyeTV hybrid stick and I haven't even started on getting that to 
work. It looks at me ... "support me, support me". Creepy little thing.


HTH,

Dan

[ I don't mind discussing more specific things, except for creepy little 
things that whisper "support me", but off list then please ]


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