Mailing List Archive: playback quality

playback quality

Nov 10, 2002, 2:30 PM

Post #1 of 5 (1402 views)

I've got my mythtv setup and running normal now, but
the quality is not all that great. I am using my
older machine which has:

AMD T-bird 1200Mhz
GeForce 2 MX 400
SoundBlaster AWE64 ISA :(
WinTV-dbx 401
IBM 25GB UDMA HD @ 14.81MB/s
Gentoo Linux 2.4.19
rtjpeg codec

I am wondering how well this machine should perform.
My picture when watching tv on my monitor is not all
that great ... I am going to assume this is the fault
of my gf2 MX. However the card should be more than
capable of doing 60fps on any resolution with better
rates than a tv. Would a radeon or gf3/4 serve me
better?

Its obvious my sound card is old and junkie ... but
its for testing right now. I would like to get one of
the audiophile cards ... what is the driver support
like in linux? is it easy to get these cards running
and configured using alsa in linux?

I also know the tv card is a bit cheap ... but it
should do the job right? Will a better tv card help
anything?

And finally the processor and HD. Most people said
that a 1GHz or more machine should work for even the
mpeg4 encoding ... and while my machine isn't blazing
... it should be fast enough right? The HD is slow
and I am planning on adding a newer drive to do all
the recording for mythtv ... is 14.81MB/s why things
are going slow?

Hopefully the answers will compile nicely into a
"System Recommendations" doc.

-- Allen

__________________________________________________
Do you Yahoo!?
U2 on LAUNCH - Exclusive greatest hits videos
http://launch.yahoo.com/u2

Re: playback quality [ In reply to ]

tarek at tarek

Nov 10, 2002, 5:19 PM

Post #2 of 5 (1359 views)

Permalink

Hey!!

I had an almost identical setup to this.. the thing I think you're doing
incorrectly is using the rtjpeg codec.. try switching to mpeg4.. You
certainly have a system that can handle it..

On my 1200 running many other server applications (our linux is our main
system), I was able to get 480x480 running smoothly.. You may be able to
get it up to 640x480, but I don't know.. It all depends on what else your
system is doing..

Well, good luck, and let us know how it goes..

tarek : )

> I've got my mythtv setup and running normal now, but
> the quality is not all that great. I am using my
> older machine which has:
>
> AMD T-bird 1200Mhz
> GeForce 2 MX 400
> SoundBlaster AWE64 ISA :(
> WinTV-dbx 401
> IBM 25GB UDMA HD @ 14.81MB/s
> Gentoo Linux 2.4.19
> rtjpeg codec
>
> I am wondering how well this machine should perform.
> My picture when watching tv on my monitor is not all
> that great ... I am going to assume this is the fault
> of my gf2 MX. However the card should be more than
> capable of doing 60fps on any resolution with better
> rates than a tv. Would a radeon or gf3/4 serve me
> better?
>
> Its obvious my sound card is old and junkie ... but
> its for testing right now. I would like to get one of
> the audiophile cards ... what is the driver support
> like in linux? is it easy to get these cards running
> and configured using alsa in linux?
>
> I also know the tv card is a bit cheap ... but it
> should do the job right? Will a better tv card help
> anything?
>
> And finally the processor and HD. Most people said
> that a 1GHz or more machine should work for even the
> mpeg4 encoding ... and while my machine isn't blazing
> ... it should be fast enough right? The HD is slow
> and I am planning on adding a newer drive to do all
> the recording for mythtv ... is 14.81MB/s why things
> are going slow?
>
> Hopefully the answers will compile nicely into a
> "System Recommendations" doc.
>
> -- Allen
>
> __________________________________________________
> Do you Yahoo!?
> U2 on LAUNCH - Exclusive greatest hits videos
> http://launch.yahoo.com/u2
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev@snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-dev
>

RE: playback quality [ In reply to ]

rkulagowski at thrupoint

Nov 10, 2002, 5:58 PM

Post #3 of 5 (1368 views)

Permalink

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Just as another datapoint, I can get smooth 640x480 RTJPEG video on
my PIII/733Mhz, but only if I'm not trying to watch live TV (meaning
a simultaneous encode and a decode) If I let it do one or the other,
then it hovers at just a little less than 1.00 on "top", so I've
taken to recording everything and then watching it later.

That's why I'm looking forward to separate encoders / viewers, since
I have multiple systems, but not one that's beefy enough for a decent
resolution while running live.

(Although CompUSA's AMD2000 + MSI KT3 motherboard for $199 is
tempting...)

Bob

-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 7.0.3 for non-commercial use <http://www.pgp.com>

iQA/AwUBPc8Ay/c1NpCTlP0JEQJ40wCeNKBcfYAlZYul4FuCPkSwcZoFcTAAn2Q9
qV2FyJcLTV1E/ielpdcodJ0s
=vEyg
-----END PGP SIGNATURE-----

Re: playback quality [ In reply to ]

maillists at sonictech

Nov 10, 2002, 7:30 PM

Post #4 of 5 (1338 views)

Permalink

On Sun, Nov 10, 2002 at 01:30:56PM -0800, Allen T. Gilliland IV wrote:
> I've got my mythtv setup and running normal now, but
> the quality is not all that great.

Could you be a little more descriptive? Is it jerky, slow, lots of
compression artifacts what? Does it change if you just record and palyback
later rather than watching while recording? What resolution are you
encoding at?

> I am using my
> older machine which has:
>
> AMD T-bird 1200Mhz
> GeForce 2 MX 400
> SoundBlaster AWE64 ISA :(
> WinTV-dbx 401
> IBM 25GB UDMA HD @ 14.81MB/s
> Gentoo Linux 2.4.19
> rtjpeg codec
>

How was that hard drive speed measured? At first glance I'd say that could
be your bottleneck. Do you have any other specs on the drive?

> I am wondering how well this machine should perform.
> My picture when watching tv on my monitor is not all
> that great ... I am going to assume this is the fault
> of my gf2 MX. However the card should be more than
> capable of doing 60fps on any resolution with better
> rates than a tv. Would a radeon or gf3/4 serve me
> better?

A faster video card isn't going MythTV one way or the other IMHO.

--
Ray

Re: playback quality [ In reply to ]

alleng4 at yahoo

Nov 11, 2002, 2:07 AM

Post #5 of 5 (1364 views)

Permalink

The quality loss I am getting in the video looks like
the video isn't able to keep up. The frames have
tears in them that flicker ... not a whole lot ... but
enough and constant. I am also losing frames
regularly. I would guess that it is my cpu not
keeping up ... or my HD not keeping up.

I measured my HD speed using hdparm.

#hdparm -t /dev/hda

15MB/s seems awful slow to be doing writes and reads
from the disc constantly ... especially recorded video
and audio.

I am doubtful that it is my video card, tv card, or
sound card ... however I was getting much better
playback on my normal station ... a 2.4GHz + gf4 Ti
... so there is some difference between the two that
is causing this loss of quality.

-- Allen

--- Ray <maillists@sonictech.net> wrote:
> On Sun, Nov 10, 2002 at 01:30:56PM -0800, Allen T.
> Gilliland IV wrote:
> > I've got my mythtv setup and running normal now,
> but
> > the quality is not all that great.
>
> Could you be a little more descriptive? Is it
> jerky, slow, lots of
> compression artifacts what? Does it change if you
> just record and palyback
> later rather than watching while recording? What
> resolution are you
> encoding at?
>
>
> > I am using my
> > older machine which has:
> >
> > AMD T-bird 1200Mhz
> > GeForce 2 MX 400
> > SoundBlaster AWE64 ISA :(
> > WinTV-dbx 401
> > IBM 25GB UDMA HD @ 14.81MB/s
> > Gentoo Linux 2.4.19
> > rtjpeg codec
> >
>
> How was that hard drive speed measured? At first
> glance I'd say that could
> be your bottleneck. Do you have any other specs on
> the drive?
>
> > I am wondering how well this machine should
> perform.
> > My picture when watching tv on my monitor is not
> all
> > that great ... I am going to assume this is the
> fault
> > of my gf2 MX. However the card should be more
> than
> > capable of doing 60fps on any resolution with
> better
> > rates than a tv. Would a radeon or gf3/4 serve me
> > better?
>
> A faster video card isn't going MythTV one way or
> the other IMHO.
>
> --
> Ray
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev@snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-dev

__________________________________________________
Do you Yahoo!?
U2 on LAUNCH - Exclusive greatest hits videos
http://launch.yahoo.com/u2