I'm attempting to build DVD support into my copy of Minimyth

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Eduardo
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Location: Winnipeg, Canada

I'm attempting to build DVD support into my copy of Minimyth

Post by Eduardo »

Well I've decided to stop talking about doing it, and finally getting around to the incorporation of my slimline DVD into my Minimyth system. (My wife snagging the DVD player for the kids play room helped...)

So my first step in this process is to leverage available assets, which of course is the immense brain power of these forums.
1. Has anyone done this, if so any stumbling blocks to watch out for?
2. I haven't played with cramfs but, is the /dev portion of minimyth going to need to be recreated, so that I have a device to refer to? I do see the DVD detected during start-up.
3. Did anyone go as far as to replace the mplayer install with the VeXP version of xine (mpeg2 enabled)?

Thanks for any insight, I'm off to read Larry's article on the creation of MiniMyth.

Of course if someone has already built this and "re-crammed" their filesystem for an M10000, I would be more than excited to just try theirs out.

Eduardo
Eduardo
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Post by Eduardo »

Progress report:
Well a few things, thanks to Larry for using devfs. That bit of planning makes the whole thing MUCH easier than I ever anticipated. With 30 minutes of tinkering I acheived what I thought was going to be a week of evenings or a full afternoon.

So far without altering the cramfs I've achieved DVD playback with a few work arounds.

The system recognized my DVD on boot up as /dev/hda and also /dev/cdrom.

1. I Made a symlink for the dvd device.

Code: Select all

     ln -s /dev/cdrom /dev/dvd
2. I added a fictious filetype to Setup->Videos Settings->File Types

Code: Select all

     Extension: dvd
     Command: mplayer -fs -zoom -quiet -vo xv dvd://1
     Use default player: uncheck
     Ignore: uncheck
3. Make a fake file in your videos directory. Call it anything you want but make sure it has a matching extension that you defined above. In my case:

Code: Select all

     touch /myth/mythvideo/a_movie.dvd
I chose something that started with "a" so it appears first in my videos list.

Now you can select a direct dvd from your front-end through the "browse videos". The audio bug is an issue, you gotta jump to mythmusic to initialize the sound if you hadn't already, that is fixed in myth's cvs I hear.

Playback seems to still be a bit jerky in playback, a sweeping camera movement has some micro pauses. Not too noticable if you aren't looking specifically at playback performance. Of course now that I know it's there it'll bug me. If I rip the dvd it plays fine over NFS, so perhaps there is a DMA issue on the drive or something. I'll have to look into that tomorrow.

I also noticed that mythmusic would crash with the one audio cd I had put in the dvd, not sure if it's that disk or something else.

Of course I will eventually look at mythdvd, but if I can get away with it in mythvideo I may just wait.
lmatter
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Post by lmatter »

Good Job Eduardo, thanks for sharing your success.

The decision to use devfs grew from one of my frustrations with freevix, that you had to be root to untar it because the tarball had /dev nodes that could only be made by root. I wanted to see if I could buld the distribution completely as "Joe User" and devfs was the way to go.

WRT the cd crashing minimyth, that is a known issue (known to me anyways). I found that any access to the cdrom from mythmusic would crash. Works fine from mythgallery (when importing picture cds). Didn't have time to debug it, I figured I would just rip on my server machine. But I think even having a cd (or dvd) in there and hitting the wrong menu will make it crash.

Larry
Eduardo
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Post by Eduardo »

Mythmusic:
Yep, just having a cdrom in makes mythmusic crash. It did not Crash when a dvd was in though. I'll try a data CD. I think the kernel does not have support for udf but does have support for iso9660. That was the only difference I see between my backend machine and minimyth for the cdrom. (Audio CD's are udf?)

DVD update:
DMA was off on the DVD drive, more kudos to Larry for including "hdparm" so you can turn on DMA.

Code: Select all

/sbin/hdparm -d1 /dev/dvd
DVD playback was fine once DMA was enabled.

Now my only issue is that DVD's and DVD rips seem to be at a third the volume of MythTV captures and regular TV volumes.

Eduardo
Funkstar
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Post by Funkstar »

That will be because of the Dolby Digital/DTS encoding leaving enough bandwidth in the signal to reproduce explotions etc.

Would be good if there was a pre-amplification setting in Myth for this, don't know how feasable that would be though.
Eduardo
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Location: Winnipeg, Canada

Post by Eduardo »

Thanks! I always wondered why, never thiught there may be a "spike" or a safety margin for one, in the audio...
Funkstar
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Post by Funkstar »

I only know because i had the same 'problem' when i stated using my DVD player and surround amp as a CD player and had to keep drasticaly changing the volume settings depending on what sort of disk was in the drive :)
slifox
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Post by slifox »

I'm not sure if you also meant dvd playing abilities, but in minimyth 0.2-jm i hacked up my own version of mythdvd to control things like the title (some badly made dvds dont have the feature on title 1 or whatever), subtitles, etc...

I've setup my minimyth-0.5beta1 to play dvds, and as soon as I get a hold of a dvd :) I'll test it and let you know how it turns out

-alex
Eduardo
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Post by Eduardo »

I've just been lazy about diving into cramfs.

What were the steps you did to integrate mythdvd? Just uncram, compile mythdvd and recram? I noticed that my binaries "appear" to be compatible with the myth install, I'm almost tempted just to extract the files out of the RPM and add them in, recram and cross my fingers.

The one short coming of my workaround is you have to figure the title number like you mentioned. Works great if the title is 1, but you'd have to re-edit or add another filetype for title 2, 3, 4, etc.
slifox
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Post by slifox »

I've been trying compiling my own and using the one from minimyth-0.2-jm but I've haven't been able to get my hands on a DVD recently. Hopefully this weekend I will. Also, I've setup my minimyth-0.5beta1 to mount /usr off of NFS (this takes a bit of work but isnt too hard). This makes it a lot easier, as I don't even have to reboot to try changes out. Plus, boot times are much faster (especially if you're thinking of adding in big programs/etc)

-alex
lmatter
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Post by lmatter »

Eduardo, if you don't want to bother with uncraming, just download the tar file. You still have to mkcramfs to boot it.

I start the mkcram, wait a couple seconds and then reboot the frontend, and have another root window ready to copy the image to the PXE area. I can restart in about 1 1/2 minutes.

/usr on NFS is faster of course; I haven't taken the time to set that up yet.

Larry
slifox
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Post by slifox »

Larry: the only things I really had to do were (besides mounting /usr from preapp.script) make identical symbolic links in /bin/ of all the commands in /usr/*bin/ that link to busybox. Additionally, I had to copy over udhcpc to /bin/. Then just remove the translucency setup for /usr/share/mythtv/ and you're good to go (I think thats it).

-alex
slifox
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Post by slifox »

Success! DVDs work in my minimyth 0.5. If anyone wants to take a look let me know and I'll package it up... It uses NFS for /usr, mplayer from minimyth-0.2-jm, and a custom mythdvd that has options for subtitles/captions/which title to play.

-alex
Eduardo
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Location: Winnipeg, Canada

Post by Eduardo »

why the different mplayer?
slifox
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Post by slifox »

I didn't realize there was an mplayer in 0.5, because larry had said that he wasn't going to put dvd support into minimyth until the hardware decoding was supported. :)

Also, if you're having trouble playing (it works fine on my M10000 but may not on a 6000), try putting the -framedrop option in..
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