[mythtv-users] Request info from working M10K frontend.

[Michael Carland]

Thanks to everyone for the replies.

I'm going to try installing knoppmyth, and upgrading it to .18, since 
that is what the backend is now, and I had the same problem with .17. 
Since Jon has it working, and his interrupts look the same as mine, I 
can stop going down that path.

I did try a pci nic, and it had a different interrupt than the video, 
but that did not solve the problem. Bummer.

I sat squinting at the "-v all" logs into the wee hours last night, and 
came up with this puzzling thought:

I assume the capture card has to capture at the rate the video source 
is clocked at, and in my case, the audio is sampled at 48kHz. On the 
front end, the video is written in sync with vertical retrace, and I 
assume the audio is written in sync with the video according to timing 
info in the stream.

My question is, what happens if the video source rate is slightly 
slower, or the because of my video modeline, the output is slightly 
faster, than the standard. Or forget the standard, what if the source 
is slightly slower than the sink. I know the standard sets the display 
rate, but no two clocks are identical. In the case of live tv, would 
the ringbuffer slowly be drained, causing the pauses when it runs out? 
Or is myth able to compensate somehow? How about the audio, what 
happens if the frontends clock is slightly faster than the backend, is 
myth able to adjust the audio output rate, or does the audio buffer 
drain, causing pauses?

What I see in the logs is a REQUEST_BLOCK _RI immediately after every 
Read(). At first the time of the Read() after the request is very 
short, but then bumps up to a slightly larger number. At this point, 
the audio buffer is slowing falling behind, until it runs out and 
pauses. When it restarts, there is a brief period of fast responses 
from the backend, but it then falls back to the old rate, the audio 
buffer again falling behind.

I'm going to try and graph the response times, the audio buffer size, 
and the pauses, and see if I still see that pattern, now that I've had 
some sleep.

Thanks,

-Michael