I have just built my first Knoppmyth MythTV box and all was going well until I got my Hauppauge Nova-T-PCI (90002): -

Live TV picture appears to be slow motion, sound appears to be very slow and slurred (quite eerie). Using dvbstream shows the same problems outside of MythTV.

MythTV completed Recordings are perfect, unless they are still in the process of recording in which case the same problems occur.

If I change my sound in MythTV from ALSA:default or /dev/dsp to /dev/dsp1 (non existant) then the live tv picture appears normal, but naturally there is no sound.

It seems that it doesn't like streaming uncompleted files as a completed recording plays perfectly. Is my machine too slow?

Specs are: -

Knoppmyth R5D1
Athalon XP 1700
512 MB RAM
Maxtor HDD
Asus A7N266 with on board sound (CMI8738) - although I also get the same problem with an ALI PCI soundcard
MX440 graphics card (not using TV out as yet)
Hauppauge Nova-T-PCI (90002)

I'm so very close to getting everything working and would appreciate any advice or guidance to find the fault. However I am quite new to this stuff!!!

Many Thanks

I would suggest trying a pci sound card and disabling the onboard one, but looks like you've tried that!

Also, you say it was all going well until you got the Nova-T, did you have a different card in there before that worked perfectly?

If not, I think the hard disk could be causing the slow down, it can keep up with recording a show, and playing a show, but not recording and playing at the same time. Try following these instructions on the wiki:
http://knoppmythwiki.org/index.php?page ... erformance

I don't think it could be the slow cpu, as I used to have my Nova-T running in a PC with a P3 933.

Thanks for the suggestions

Yes, I disabled the on board audio and tried a PCI soundcard which did exactly the same.

I will give the hard disk optimisation a go.

I do however get the same issue using DVBStream outside of MythTV, so there should be no recording happening at that point.

One further note is that when in live TV when you press esc to exit it seems that the audio problem corrects itself for the split second or so before you are returned to the main menu.

Thanks again.

Interesting that you get the same problem with DVBStream, deffinitely try the hard drive optimisation! I think sometimes in the bios you can set the hard drives to pio or udma, might be worth checking there aswell.

To follow on from mad_paddler's post, they should be set to udma, and you should check that you have that set up in linux by running hdparm from the command line:

hdparm /dev/hda

To turn on DMA:

hdparm -d 1 /dev/hda

Also ensure you have 32 bit support on:

hdparm -c 1 /dev/hda

Thanks for the tips, I have checked the hard drive config, DMA and 32 bit support were already on.

Out of interest I removed my MX440 AGP graphics card and used the motherboard's on board geforce2 but the same symptoms occur.

I tried setting TV to recording and then playing back a video file (DVD rip) within MythTV. The playback of the video file ran slow. This still suggests the PC cannot cope with the demands. That does not explain why the Nova T doesn't work properly using DVBStream. What exactly does the Nova T do differently when watching live TV rather than recording it to disk for playback later?

Are there any alternative drivers for the Nova T?

Any advice would be much appreciated.

I meant to mention this earlier, but have you ssh'd in while watching or using dvbstream and checked the CPU usage?

When you watch live tv, it records to a file on the hard disk & plays it back from the hard disk at the same time (so you can pause, rewind etc) likewise when using dvbstream it does the same thing.

Whilst in Myth I checked the CPU usage and when changing channels total usage was up to 75%. Settling to around 50% after a few seconds - 35% backend, 15% frontend. Not sure what a good figure should be, memory usage seems high but again I'm not sure what is the norm when Myth is doing such a job.

Maybe there is a hardware incompatability or a driver issue.

Thanks again

Doesn't sound too high, i'll check how high mine is tonight.

One thing to check is when checking cpu usage top shows a % called WA which is waiting for i/o. Might be a good one to check!