[pvrusb2] How good is support for HVR-1950?

[Mike Isely]

On Sun, 26 Oct 2008, roccomoretti wrote:

> I'm looking for a good ATSC+NTSC tuner, and trying to avoid any 
> "gotchas" after purchasing.  The linuxtv.org wiki lists the Hauppauge 
> HVR-1950 as a "Supported ATSC USB Device", but doesn't have a subpage 
> about it. The pvrusb2 site makes it sound promising, but I'm wary after 
> encountering too many "It works ... (but, oh, yeah, significant features 
> X, Y, and Z don't)" type situations on other sites.
> 
> What isn't yet working with the HVR-1950 under Linux kernel 2.6.27? (I'm 
> intending to use it with the upcoming Ubuntu 8.10 (Intrepid Ibex) 
> release.) -- I know about the FM radio not working yet, and I've seen 
> the "initusbreset=0" workaround for the early 2.6.27 kernels. 
> (http://www.isely.net/pipermail/pvrusb2/2008-October/001918.html)
> 
> Anything else I should be aware of? No issues with either analog and 
> digital reception? All resolutions of digital supported? 
> Composite/S-video input too? Does the IR receiver/remote/blaster 
> function on Linux? Any audio/video syncing issues? Is ATSC EIT 
> programming information retrieval supported?
> 
> Sorry to bother the list with this, but I've spent more time than I care 
> to admit reading various webpages, and would like a straightforward 
> assessment.

FM radio does not work.

IR reception / blaster functionality is available from the P.O.V. of the 
pvrusb2 driver, but it requires an appropriate additional driver to 
operate the IR chip.  I can't speak to the state of that other driver, 
but everything needed on the pvrusb2 side is in place and to the best of 
my knowledge, works.  See a lengthy post I made just a day ago which 
should give you an idea about what this is all about.

The HVR-1950's RF tuner is a fairly new chip and there's been some 
recent thrashing in the v4l-dvb repository regarding stable support of 
that part.  (This is outside of the pvrusb2 driver.)  However best I 
know at this point is that the tuner works fine.  Thus digital and 
analog TV reception works fully.  You need to use the driver's DVB 
interface to receive digital video, and the V4L interface to receive 
analog video (and also composite & s-video since those are also analog 
sources).

Composite / S-video input works just fine.

All digital resolutions work fine - there's nothing about the driver 
that is sensitive to resolution.  When the device is in digital mode, 
all it has to do is grab the bit stream from over-the-air and pass that 
to the DVB core.  The contents of that bit stream (e.g. audio config, 
video resolution, sub-channels, etc) is of no concern to the driver 
since as far as the driver is concerned it's just an opaque bit stream.

There are no audio/video sync issues at all in digital mode (again, 
because it's just a bit stream).  In analog mode, a single chip inside 
the device (the mpeg encoder) handles the assembly / sync - not the 
driver - so it works about as well as one might expect.  Sync issues 
that I have seen in analog mode are usually the result of marginal 
behavior on the part of the app, e.g. mplayer gets antsy if there are 
real-time gaps in the stream.

ATSC program info should work just fine - again because it's just an 
opaque bit stream that the driver doesn't futz with.  There is no 
corresponding VBI support in analog mode however.

Probably the biggest issue right now is correct operation in 2.6.27, due 
to the recent deadlock issue.  The current 2.6.27.x has the fix, but if 
you are running a distro-built 2.6.27.x kernel odds are the fix hasn't 
reached there yet.

Did I cover it all?

  -Mike

-- 

Mike Isely
isely @ pobox (dot) com
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