[mythtv-users] Digital Pegs CPU
mythtv at rodsbooks.com
Sat Nov 29 19:23:47 UTC 2008
On Friday 28 November 2008 02:41:39 pm Paulin wrote:
> You are correct. I did screw up and they were the same card. Anyway I
> tried again and I believe this is the H1250 card now. Here you go.
> Size: 3195849224
That's an HD recording -- 1920x1080 resolution and 38,609,200 bps vs. 720x480
resolution and 6,000,000 bps for your other (SD) recording. Since your SD
recording is consuming 70% of your 1GHz VIA CPU's CPU time, IIRC, it's no
surprise that an HD recording will consume 100% of the CPU time and produce
stuttering results. If anything, I'm surprised it's only stuttering once
every few seconds, as per your description.
I don't want to say it's impossible to play your HD recording on your 1GHz VIA
CPU, but IMHO it's not worth the effort to try, unless you've got a sure-fire
recipe from somewhere. The way I see it, you've got a few choices:
1) Ditch the digital card, get another SD card, and record directly. This is
a good option if all your HD channels are available in analog SD form from
your cable company and if you're watching on an SD set with no plans to
upgrade in the immediate future.
2) As above, but use a digital converter box to tune HD channels. This may be
a good option if you want to receive OTA (which is going all-digital in
February) or if you want to tune some HD channels that you can't tune
directly in SD. Note that a cable box from your cable provider qualifies
as a digital converter box.
3) After recording, transcode every HD recording to SD. This will work well
if you don't mind the delay. (I'd guesstimate that it'll take 4-10 hours to
transcode every hour of HD content, given your CPU. If you've got a faster
system you can use as a transcode-only backend, the time can be reduced.)
If you've got an HD TV set, you'll lose HD quality, although your
transcoded HD recordings will probably still look better than the SD
recordings sent via an analog signal.
4) Reconfigure your digital card to tune only SD digital channels, rather than
HD digital channels. This might or might not be possible, depending on the
signal source(s) available to you. If it is possible, the resulting quality
should be similar to a downconverted/transcoded HD signal, as in #3, but
without the delay.
5) Upgrade your motherboard and CPU. Based on my experience with a 3GHz Intel
Celeron-D, I recommend at least a 3GHz Intel CPU (or equivalent AMD CPU).
A 2GHz CPU might be adequate for playing back HD content, but only just
-- there'll be very little margin for other things happening (such as
commflagging or database updates) while watching a recording.
Sorry to be the bearer of bad news, but I think you're just trying to do more
than your CPU is capable of doing.
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