I've been really happy lately with my homebrew dragon (same mobo, cpu, sound card, case, tuners, streamzap). Most primetime HD shows look great, FOX football looks great (720p), and I have plenty of idle CPU when watching these shows. Enough to do commflag while watching, if I "nice" the commflag process to 19 (I get some choppy audio if left at 17, which is what "low cpu" amounts to).

Unfortunately, our local CBS OTA is now HD.

Even with xVMC (which has dropped the CPU usage of X down below 1%) and killing commflag, mythfrontend can't get enough CPU to keep up with the zooms and pans of the 1080i CBS feed. Studio shots, close-ups, etc., are ok, with 35% idle. But when they give a wide shot with motion or panning/zooming, the cpu usage maxes out and I have lots of dropped frames. I've tried playing around with the various options, and I seem to be doing everything right.

I'm thinking of upgrading the CPU from a venice core 3200 to a dual-core X2 4200. The MoBo will go all the way to 4800, I think.

OTOH, maybe 0.20 will bail me out somehow?
Any thoughts? Particularly from anyone who DVRd the HD Buffalo-Boston game today?

What deinterlacing and filters are you using? Have you tried other deinterlacers?

I'm using the Bob Xvmc deint. It's the best on my system by far. I tried with/without the sync to vblank option, no difference.

Are you positive you're not seeing the results of a weak signal?

I was watching US Open in HD on my CBS affiliate (which is also 1080i), using Bob deinterlacing, on a Athlon 2400 and XvMC, and everything was hunky dory. But they definitely weren't doing pans like in football coverage.

Have you tried linear blend deinterlacing?

Also, are you sure XvMC is on? You can tell because your on screen display is grayscale instead of color.

No, only Bob. I thought that was the only one that worked with XvMC? Maybe I had that wrong. I'll re-check it.


Definitely Greyscale OSD, yes.
Also, X is using 1% CPU, where it used 30%+ before R5D1.

That DOES help a little, thanks. The CPU still sometimes bumps up to 99.9% usage on mythfrontend, but not as often, and it's not as "dramatic" on the screen. This will definitely help.

It's interesting. When watching the canned segments showing the CBS/NFL graphics and clips, the CPU is around 55% used (mostly by mythfrontend). But as soon as they start the live shots, it's 85% to 99%, depending on how much movement there is.

I could try the problematic show on my reference v1.1 Dragon if you make the video available to me. I don't suppose any of the problematic parts are toward the beginning of the show, are they?

In my experience, 720p shows use about 75% CPU and 1080i shows use about 62% CPU, with libmpeg2 as the decoder. With XvMC it would be less, so if you're seeing 99.9% usage with it and a 1080i show, I'd like to have that content for my testing.

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I will try to snip some out and I'll PM you with the location. Probably tonight or tomorrow. Yes, there was some during the first few minutes. I think I can cat/head/tail the file to whittle it down to a minute or two of useful data.

I grabbed the sample clip, and I did a quick test in mplayer, and it played without audio or video stutter on my v1.1 Dragon. I'll trick MythTV into playing it as a TV show for my next test.

I need to re-install R5D1 (testing R5D5 at the moment) to test with the same software you are using. You're using the stock R5D1 software, correct? You didn't grab a SVN version of MythTV 0.20 or anything?

Have you noticed any other 1080i shows exhibiting the problems, or just this one?

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Yes, it played ok here in mplayer.


Yes, that's what I did too. Swapped with another show. This DID exhibit the problem.



Right - stock R5D1.


I have a hint of stutter now and then, but this was by far the worst. I haven't watched any NBC football though, but I suspect it won't be as "bit intensive" as CBS, as our local NBC OTA has a weather subchannel. CBS is the only 1080i that I get that uses all of their bandwidth for HD.

Ok, so we know the hardware is capable of playing that clip without issue. Mplayer isn't even using XvMC by default - it should have an easier time playing it back in Watch Recordings. The problem must be something about how MythTV is behaving on that content.

The fact that you're seeing any stutter at all makes me wonder if you've run into something similar I've seen before.

A while ago, in the course of doing a long series of upgrades of my Dragon to test prerelease KnoppMyth versions, I started seeing video stutter. I haven't seen it since that long upgrade string. I couldn't figure out why it had begun, but - long story short - there was a consistent fix for it. A fresh auto install cleared the problem up. At the time, I did not determine what about a new install cleared the problem up - it either had to do with the reformatting or the re-initialized MySQL database.

Before you attempt anything further, did you upgrade to R5D1 or install it from scratch? If it's an upgrade, you may be experiencing what I saw before. If not, then it needs to be further investigated.

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It was an upgrade, yes, from R5C7. I was not able to use XvMC on that one, so my X CPU usage was very high.

Regarding mplayer, I probably didn't do it right because the screen wasn't matching the output. Maybe it was playing at my GUI size of 720? I've got separate sizes for GUI vs. playback, to help with displaying xterm windows. mplayer didn't size right, and there wasn't any audio. So I didn't see it all, but what I saw looked smooth.
Anyway, that was probably a bogus test, the way I had things set up.

One of these days I need to write an "only keep my recordings" filter for the backup/restore...

Not matching in what sense?

Just running mplayer on it directly should have caused it to play the video and audio. Does mplayer normally work for you?

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It was chopped at the bottom and right. As if mplayer only had 720 to work with instead of 1080. Which was probably the case, as I run the GUI in 720p mode. I use the "separate sizes for gui and playback" option, to play 1080i TV as 1080i.

I don't normally use mplayer for anything so I don't know if the sound normally works or not. I use XINE for DVDs.
Did you try playing the clip through Myth?

[edit]
BTW, I had an error while posting this. Some SMTP error about having insufficient storage to send e-mail. If you have the forum set to e-mail you with replies, it may be crapping out.