[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Edlug Archive Jan 2004 ]

Re: [edlug] Anyone want to give an edlug technical talk on PVR/DVB?

On Mon, 5 Jan 2004, Greg Lewin wrote:

> I've been having similar ideas, since it looks as if mini-ITX boards are 
> an idea whose time has come  - 1 GHz is plenty for most applications 
> including sound & vision, and the notion of silence from the box itself 
> is very attractive.

I'm building a PVR based around a VIA M10000 motherboard, and the WinTV 
Nova-T card. The Nova-T card is DVB, so you get a digital stream, and 
shouldn't have to worry about the processor load of the encoding step.

> For starters I'm wondering which PVR card to go for: one I've been 
> looking at is the Hauppauge WinTV-PVR-350 (internal), or possibly the 
> Hauppauge Win TV PVR USB (external). 

The PVR 350 has a hardware MPEG-2 encoder and decoder. The USB PVR model 
doesn't appear to have a hardware MPEG-2 encoder, the USB 1 version 
will only support recordings of up to 6 MBits/sec.

You may not find the lack of a hardware MPEG-2 decoder a problem, 
especially if you're using a motherboard (such as the M10000) with 
hardware MPEG support [1]

> I have had an old Hauppauge Tv card for 
> a few years now; it gives good enough live pictures, though I don't 
> think it's usable for recording high-quality video to disk - unless it's 
> possible to pipe the output into a soft MPEG encoder 

This is what quite a few people have been building PVRs out of. In 
fact, Hauppauge cards now come with a 'SoftPVR' for Windows which allow 
you to time shift and record straight from these kinds of cards. Of 
course, you can pretty much kiss your processor goodbye whilst doing so 

On the Linux front, MythTV supports soft encoding, and you can 
downsize the resolution in order to fit the abilities of your 
processor and disk. Bear in mind, however, that if you want to do things 
like 'pause live TV' your processor has to fast enough to support both 
encoding and decoding simulatenously.



[1] Note, however, that the support for hardware MPEG on the M10000 is 
dependent on either binary drivers from VIA, or on a reverse engineered 
set of drivers, which are under very active development.

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