[mythtv-users] Comcast Analog/Digital Future (was: Using Two DTAs with One PVR-500)

Devin Heitmueller dheitmueller at kernellabs.com
Thu Jan 21 00:11:25 UTC 2010

On Wed, Jan 20, 2010 at 7:00 PM, Brian Wood <beww at beww.org> wrote:
> On Wednesday 20 January 2010 04:47:32 pm Ben Kamen wrote:
>> On 1/20/2010 5:02 PM, Karl Newman wrote:
>> > I recently was forced through the Comcast digital strainer
>> This whole discussion has been very interesting as I've been contemplating
>>  getting another PVR-xxx or so to record additional channels on Comcast.
>>  But it sounds like with ComCast switching off the Analog, my PVR-350 might
>>  be good for Composite/S-Video input at some point in my near future.
>> I think the only question there is: (since I don't know) -- Do the
>>  non-tuner inputs pipe through the onboard MPEG encoder or do those video
>>  inputs become high-cpu-usage video capture devices?
>> Answering this would finalize my motivation to avoid (like the plague) all
>>  the suddenly available analog-only PVR cards showing up on ebay.
> All inputs to PVR cards are encoded by the on-board hardware. There is no way
> to get frame-grabber like performance from a PVR.

Perhaps I am misunderstanding the question, but with most of these
cards you can collect either the MPEG encoded output *or* the raw YUY
video (depending on how complete the driver support is).  So I'm not
sure what you mean by "frame-grabber like performance".  If the goal
is low latency, then you can bypass the encoder entirely.

But to Brian's point, you typically choose the input routing (which
decides which input gets used).  You cannot simultaneously capture on
both the tuner input and the composite or s-video input.


Devin J. Heitmueller - Kernel Labs

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