• Published on | Aug 02, 2006 | by Chris Osborn

I want to build an archive without filling my disk

I finally got the living room box rebuilt with a new MythTV which is compatible with my backend. Now I can see that the HDTV tuner card is really working. I also set it up to netboot, man what a difference! It's so quiet now without an HD inside it whining away.

I discovered that KTXL is broadcasting their digital stream at 1280x720 and 60fps. No wonder my 866mhz P3 can't keep up and stutters trying to play it! The obvious thing to do is to transcode it down to a resolution that it can work with and will look just fine on my TV which is just a 27" Sony Vega hooked up via S-Video.

Unfortunately I'm having a heck of a time finding any real documentation on how to transcode and what settings I want to use. I've found I can reduce the width to 640 and convert to DivX to save space, but that's about it. Since the shows I'm recording are only 4:3 and not 16:9, I need to find a way to crop the black edges off. I'd also like to reduce the frame rate down to 23.976 which is what a lot of my other stuff is and it looks just fine. I can't find any settings to do that.

I found something on the MythTV wiki where Steve Adeff mentions he has a script to transcode into what "the scene" terms an HR HDTV encode. Unfortunately the script or details on settings is not there, and I couldn't find a way to contact him and ask.

I've also found some sites mentioning using "User Jobs" but no details on how they work. From what I've seen on some sites, a User Job will just make a copy of the recording, which isn't what I'm after. I want to replace the recording with a reduced size encoding, just like using the Transcode profiles does. It's possible that the User Job can do this inside the script itself, but I have yet to find any details about how to go about doing that.

I also played around with the commercial removal. The automatic detection hasn't worked yet, but doing it manually wasn't too bad. One of the few interface things that isn't hard to grasp. Of course this raises an interface issue: Why are there two different viewers for video? Why is there one for "recorded" video and one for "other" video? I would much prefer to have all my video in one place, where I have the same controls and same ability to work with it. Right now it's very annoying because the MythTV viewer uses different keys than mplayer, so I can't skip around the same way. I found I could make the MythTV viewer "remember position" so I can resume playing from where I was (although it should just remember position when I exit, not force me to set the position manually). This is something I have been missing from mplayer, and another reason that all video should be viewed with the same program.

I'd also like to see a real fast-forward, instead of just skipping around. My guess is the skipping happens because it's hard to simply offset into the file and find a frame. All it would take is some job that runs and indexes the video file and locates all the keyframes and saves the list somewhere. Then when fast-forwarding the player would have a table so it could quickly locate offsets.

Scheduling a show is also pretty crazy. When you do finally struggle far enough through the interface that you get into a menu to set up recording, you basically get two modes to record things: "VCR mode" and "wishlist mode". Why anyone would want VCR mode I have no idea. In VCR mode you pick weekly/daily and it locks in the time&channel, so if the show moves or is aired an extra time (like 2 new episodes in a row) you're screwed. The sites that talk about setting up recording even warn you about this. Kind of defeats the purpose of having a computer downloading a guide to track shows.

Yes, I know, if I don't like it, I have the source and I should fix it instead of rant. I've actually been thinking a lot about fixing it (or starting over from scratch), but I'm just not there yet.

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+1  Posted by casey • Aug.21.2006 at 16.51 • Reply

Here is the script you're looking for

http://www.gossamer-threads.com/lists/mythtv/users/207309#207309

I didn't get it to work properly for me though. So I wrote my own.

There is also this... http://www.myhdbox.com/mythtips/2006/05/tip-4-transcode-profiles-for-hdtv.php

Try installing mythweb and scheduling form another computer though a web browser.