[mythtv-users] Motorola 6200 firewire high def artifacts - Help me debug?

[Greg Mitchell]

Steven Adeff wrote:
> On 7/18/06, greg at nodecam.com <greg at nodecam.com> wrote:
>>> I am also trying to solve an issue with a Motorola firewire box.
>>> Could you describe the artifacts you are seeing. Do they crash your
>>> backend? Have you tried switching from a point-to-point connection to
>>> a broadcast connection? Have you tried increasing the firewire speed
>>> in MythTVSetup.
>> Basically it's like a skip in the stream - the whole screen goes very
>> blocky, then resolves itself.  When watching the NHL playoffs, it was
>> doing it every 10-20 seconds during play, making the game unwatchable.
>>
>> I can't get broadcast working, and firewire speed is set to 400 already
>> (though I'll have to check on that to confirm)
>>
>> The backend is still stable though, it's just frustrating not being able
>> to really use the system to record high def sports.
>>
>> I did some benchmarking on the hard drives, and they seem to be able to do
>> sequential writes plenty fast for HD - I'm wondering if I have a bad
>> firewire cable.  I guess replacing that is my next logical step.
> 
> does your cpu usage spike while recording?
> 

Nope, sadly, the CPU is relatively idle the whole time.  I had it 
logging everything for an unrelated reason, and when I removed that from 
the picture, things seem improved.  I'll have to see if it's still 
better when the next football game is on in HD (should be Friday I think)

On a lark, I tried recording via test-mpeg2 and watching that - perfect. 
  I wonder if the extra logging was causing my write performance to drop 
because it was interleaving writes instead of doing a sequential write - 
doesn't make a lot of sense to me, but who knows.

I'm on an AMD64 3200+ system FWIW.

I'll update the list if things are fixed.

Greg