pimp my mythtv

I’ve been having a lot of fun with my mythbox lately. I’ve learned some really cool stuff about Myth, MPlayer, LVM2 and multimedia in general that is really helping to polish my setup. Add to that the fact that I’ve been working on dvd::bend quite a bit lately, and getting some bugs taken care of, and things are really adding up. I also finally took the plunge last week and bought my first 750 GB harddrive. I’m up to 1.6 TB of space in my server now (5 harddrives in one box), and I haven’t even hit 50% capacity yet. I’m sampling a little bit from all my TV series and getting them on there, so I can at least watch something from everything I have. Eventually, somewhere down the road when I have lots more space, I’ll have everything completely archived. For now, I’m still experimenting and getting used to the setup. It’s getting pretty nice.

Here’s some of the cool little stuff I’ve found out recently.

mythtv custom menus

I didn’t know this til just the other week, but the design for the menu layout that Myth uses is all in XML files, and right there in the themes directories (/usr/share/mythtv/themes). That said, you can customize them all you want! Just read the docs, and you’ll be up and running in no time. It’s really simple. It took me just a few minutes to simplify my main menu so I can jump to the TV recordings and MythVideo really easily.

mythvideo gallery view

I’m really having fun with this one. There’s a few things I’d change, but for the most part it works great. Here’s what my layout looks like right now:

mplayer + xvmc + high motion

I just barely discovered this tonight. One of my frontends is a Pentium 4 1.6 gHz, which does plenty well. You really don’t need that much horsepower to play back video. It’s got an older nvidia AGP card in there which works just fine with s-video out. The only problem I have is that there is sometimes a slight stutter on the video with some high-motion scenes. I’ve actually started to get used to it, but then I found out that using the XvMC video out option really makes things much smoother.

At first I was just playing with it to see if I could get the CPU usage down. It was only dropping by about 10%, which wasn’t that great, especially since it was still running high … around 35%. Turns out I had cpufrequtils set to use the powersave governor, so my CPU was only running at 400 mHz. Whoops. I bumped it back up to full speed, and mplayer dropped down to around 10% total.

But, even then, at the lowest speed, the video looked gorgeous. I’ll admit it might have been my imagination, but those motion blur issues seemed to go away. I was so surprised by the results that next I ran it through the Star Trek test (which everything has failed), and played back some Deep Space Nine. Normally I’ll test TNG since I’m extremely picky about the video quality on that one, and I’ve seen them enough that I can notice video artifacts more easily, and this was only the 2nd time I’ve seen this DS9 episode. But, it still looked nice. I could notice some small amounts of blur, but it was pretty minimal. So, who knows, that solution might work well for everything. We’ll see. I’m feeling pretty optimistic about it, and at the very least it works great for my older TV.

mplayer + audio delay

Before that, I was taking a break and watching some A-Team. Great stuff. On one episode, the A/V was off just slightly. This has always plagued me in the past, and it’s one of the reasons I don’t bother with encoding files. Also, this has happened before on another Universal disc (of all the DVDs I have, they have the most problems … they are rare, admittedly, but that studio is still the winner). I remembered reading somewhere about adjusting the audio delay with mplayer, so I checked the man page. You just use + and – keys on the keyboard to adjust it by 1/10th of a second each way, faster or slower. Played around with that, and the A/V was back in perfect sync. So, I mapped my channel up / down keys on my remote to do that in case I ever run into that problem again, and now that’s all fixed too.

matroska saves the day, and disk space

This is another cool one I noticed last week. This is all anecdotal evidence, so YMMV, but I’ve noticed that Matroska files are consistenly smaller than AVIs. About 8% smaller, in fact. I noticed that quite by accident while playing around with some encoding files. At first I figured I had done something wrong, but the results proved the same after quite a few tests. That is a lot of overhead for AVI, sheesh. Just one more reason to love and use Matroska. :)

Seems like there was something else, but I can’t remember now. Ah well. Anyway, I was hoping to get all those random thoughts down sometime, so there you go. Lots of fun playing around with this stuff. I’m pretty blown away by how well it’s working and how polished the whole thing is getting. Once I’m done for good, I’ll be sure to document how to reproduce the entire step in detail. Good times. :D

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4 Comments

Filed under Gentoo, MPlayer, Multimedia, MythTV

4 responses to “pimp my mythtv

  1. Gusar

    It’s true about AVI and Matroska size. AVI has an overhead 24 bytes per frame and a lot of it for audio, especially if it’s VBR.

    Matroska has no noticable audio overhead and a very low overhead for video. If you use SimpleBlocks aka Matroska v2 (it’s an option in mkvmerge) as low as 6 bytes per frame from my experience.

    A good container comparison with hard numbers: http://www.alexander-noe.com/video/amg/en_overhead_comparison.html

  2. Chewi

    I don’t suppose you actually play any DVDs with MythDVD because you rip them all first? =P I get slight tearing during scene pans. I have enabled the XvMC option but I don’t think it affects MythDVD. Either that or it’s not working on my hardware. It’s a 2.8Ghz machine though so it should be able to handle it. I haven’t been any to find any info on the problem.

  3. Steve

    Chewi,

    No, I only watch DVDs on my DVD player. I don’t even have MythDVD installed, and haven’t even played with it in quite some time.

    I’ve had different results with different boxes when it comes to XvMC as well. I’m not quite sure I’m doing everything quite right. It does need some more research.

  4. Steve, excellent post.

    I just found the XvMC options for MythTV(http://www.mythtv.org/wiki/index.php/XvMC) this weekend, and haven’t tried them yet, but I am hopeful that the motion issues I’ve seen playing back DVD ISO files & physical DVDs will be solved for me by using XvMC.

    Here’s what I found:
    mplayer -vo xvmc -vc ffmpeg12mc

    Is that what you are using? Your previous post seems to indicate the same.

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