[mythtv-users] ivtv capture is good, but mythtv hoses it

[Michelle Dupuis]

Does is jitter if played outside myth?  Is XV enabled on your video card?
Does Xine play it ok?
 
If the video encoded ok?  (Have you played it back on another machine)?

  _____  

From: mythtv-users-bounces at mythtv.org
[mailto:mythtv-users-bounces at mythtv.org] On Behalf Of Aaron Nauman
Sent: Sunday, June 17, 2007 10:44 PM
To: Discussion about mythtv
Subject: Re: [mythtv-users] ivtv capture is good, but mythtv hoses it


On 6/17/07, Brian Wood <beww at beww.org> wrote: 

Aaron Nauman wrote:
>> > > I am running ivtv 0.10.3 on PVR 350 and PVR 150 on fc6 2.6.20.  If
> I run a
>> > > capture test with cat
>> > >
>> > > cat /dev/video1 > test.mpg
>> > >
>> > > The capture looks great.  If I start mythtv and watch live tv, I
> get jitter.
>> > >  Every couple of seconds the video pauses for a second of so. 
>> >
>> >  In MythTV, what resolution/bitrate do you have set for your LiveTV
>> >  profile for MPEG2 Hardware Encoders? If you change the resolution for
>> >  LiveTV to 720x480 do things improve? 
>>
>> Thanks for the reply Nick.
>>
>> I am running with the default settings: 480 x 480 with 368K bitrate.
> I tried 720 x 480 and get no improvement.
>>
>> I have tested my hard drive and it is getting good throughput.  Any 
> other ideas?
>>
>> Thanks,
>> Aaron
>
> I have tried changing the resolution and bitrate settings around, with
> no improvement.
> I am getting some "NVP: prebuffering pause" messages. 
> I tried output through PVR-350, but still have the jitter, so I am
> pretty sure it is on capture.
>
> I have read through the troubleshooting sections on ivtv and mythtv and
> everything else I can find with google and haven't found anything that 
> makes a difference.  And that includes rebuilding the machine from
> scratch.  I am really worried that I am going to have an expensive
> doorstop on my hands, unless someone can help get me on the right track. 
>
> Any thoughts anyone?

What sort of system? Myth puts a significant load on system resources,
if you have an underpowered CPU it might work fine running a cat command
but fall on its knees running Myth. 


What CPU and what load running Myth? Are you running X and all graphical 
stuff when you run your cat command? Is your RAM limited, ie" are you
swapping when running Myth but not when running the cat?




I don't think it is a performance issue.  I have had myth running on this
machine with no jitter problems with ubuntu.  I was having stability and
lirc problems with Ubuntu and Jarod's howto is so nice, that I switched to
Fedora. 

The machine has
Sempron 3400+ (2 GHz)
2 GB RAM

There is basically nothing running on the machine other than KDE that is
resource intensive.  No swapping happening while watching live TV, but
jitter is there. 

What I find confusing is that capture with cat jitters after exiting myth. I
seems that this would point to the problem.  I just don't know enough about
this stuff to figure it out.

Thanks,
Aaron

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