Thursday, December 08, 2005

Getting MythVideo to use 16:9 aspect ratio

When I last left off, MythTV was using my 61MD10 61" HDTV in full 1280x720, but MythVideo was stretching my HDTV .avi files too wide and showing black bars on the top and bottom. As it turns out, mplayer isn't able to autodetect the 16:9 aspect ratio.

Thanks to this post, I found that I needed to supply this information in the MythVideo playback settings.

Here's my new mplayer command:

mplayer -monitoraspect 16:9 -fs -zoom -quiet -vo xv -ao esd %s

3 comments:

Anonymous said...

Just found your blog. Great resource! I've been trying to catch up on your work from December 2004 when you started your project. I wish there was a summary HOWTO so that I could get up to speed quickly :) I'm new to MythTV and I'm still looking into what equipment to buy. I've been leaning towards the PVR-250/350 cards but I'm still considering my options. I see that you list both on your setup. Do you use one for encoding and the other for decoding? I know that that 350 does both. I am looking to have my MythTV backend and frontend on separate machines, using the 350 on the frontend and 250 at the backend. An alternative that I also considered is using the Hauppauge Digital Media Receiver MVP1000 for the frontend. I just picked one up for $50 yesterday. As far as I've learned, there has been some work on implementing the MythTV frontend on it. So far it is very limited compared to a PC based frontend implementation. But I like the idea of a silent, thin client for the frontend. If I was to go the PC route, I want to try and use some old equipment that I have lying around, like a Pentium 90Mhz, a Pentium 200Mhz, a Athlon 700Mhz, none of them fine examples of processing power. So I need to have the hard work handled by the encoder/decoder cards. Any opinions/advice on any of this.

Thanks,

Regy
Reading, PA

W. Blake Caldwell said...

Great feedback, Regy -- hopefully this response will help you out.

Let me give you my story :)

I chose the Hauppauge 350 because it's one of the most widely used with MythTV so I figured it'd be easy to setup. Plus, it has TV out, and hardware mpeg2 decoding and encoding. I planned on using this card to both record shows and act as my video card.

The mpeg2 encoding/decoding is key because my original MythTV box was a 733MHz P3. When I first was setting it up with a regular computer monitor, I think it even had a hard time playing back the recorded shows -- the processor took a huge hit. When I started using the TV out, my processor was hardly used for playback.

I later got a 250 so I could record two shows at once -- I'd highly recommend having two cards. You can use the 350 to record one show and playback another at the same time -- it's really a great pice of hardware.

Okay, so, the machine worked great for a while, but seemed to start slowing down over time, maybe due to the database growing - who knows... I had to turn off some of the really great "extra cheese" features because of this, and it would still crash from time to time (most likely an ivtv driver issue that's since been fixed).

So, I rebuilt the machine recently with a 2.4GHz P4, and it's been 10 times better! I've turned back on the extra features I had turned off, the menus are more responsive and playback navigation is near instantaneous. The upgrade was well worth the extra cash.

And then I got my HDTV with HDMI input... I bought a DVI->HDMI cable, and hooked up my tv as if it were a monitor. I'm no longer using the 350's mpeg2 decoding. Of course, my 2.4GHz has no problem playing mpeg2, so I didn't take much of a performance hit. What I gained out of it was semi-HDTV compatibility. Myth's menus are full HDTV quality, and any high-quality videos I download can play in that resolution. However, I still can't record in HDTV.

So... to get back to your question.. It's probably technically possible to use a 200MHz, but it's not gonna be a great experience for you. Commercial flagging will take forever, and the menus will be god-awful slow. You'll need the Hauppauge 350 for playback, and won't be able to play videos you drop on the box from elsewhere. The 700MHz has a better shot at it, but still, it's not gonna be great.

Here's what I'd recommend -- and believe me, when you get it working, you'll say it was worth the time, effort, and money:

** 2.4GHz (or something close to it -- I'm don't know how much of a processor you need for good functionality, but my 2.4GHz has been great)

** 2 Hauppauge 250 cards for similtaneous recording

** a fanless video card with 64MB video and DVI output. You can get these for $40 or so -- I'll find out which model I've heard recommendations for

** as much hard drive space as you can find -- I've got just over 1/2 terrabyte. Count on 1 hour taking up about 1.1GB. The best time to buy hard drives was by standing in line at 4am in front of Best buy the day after Thanksgiving -- too late!

** 512MB RAM

** Big, quiet fans running at low power -- these will be just about silent. I have one laying across my PCI cards, since the 250 & 350 seem to run hot



Okay, you got me to ramble on! Bottom line -- don't expect much out of slow processors, it's worth having a little more power -- spend $200 on a motherboard/cpu combo and you'll be very happy!

Please let me know if you have any more questions - and thanks for the feedback.

- Blake

Burt said...

Nice nice... any message board posts to back up your discovery?