moc live cd

Submitted by jefg60 on Sat, 2006-02-25 20:05

Forums:

If anyones interested I've made a live CD with SLAX and various modules, that autostarts moc on the console when it finishes booting. Its got some personal customizations in it to connect to my samba server and work with my multimedia remote control (using usbhid driver) but I could easily generalise it.

jefg60

Sat, 2006-02-25 20:06

ps im using it on a via mini itx motherboard with tv output - with the remote no keyboard is needed either.

daper

Sun, 2006-02-26 18:30

Nice :)
KDE has it's own live CD, so MOC has it also ;)

--
Damian Pietras - MOC developer

jefg60

Sat, 2006-03-11 12:21

Been tweaking it some more this morning. have found the best settings for sound quality. As it all runs in a RAM disk, I lose the playlist when the machine shuts down it also uses up all the RAM when the playlist gets big. Is there a way to save the playlist on a remote samba share? I tried the mocdir setting but it cant create the socket with that, meaning moc wont run at all. Should I be able to use a samba share as the mocdir? I suspect not, with the socket bind thing. If so is there any way to save just the playlist in another dir?

daper

Sat, 2006-03-11 14:09

There is no way to say that the playlist should be stored in other place. Can't you use NFS? If no, maybe a script that copies the playlist elseware on shutdown and moves it back at startup.

--
Damian Pietras - MOC developer

jefg60

Sat, 2006-03-11 15:30

Thanks, I'll have a go with the script idea I think. Hadn't thought of that. I've got a version of my liveCD running from a PXE boot now. Handy because removing the cd drive removes the last thing in the box that makes any unwanted noise, it being fanless :D

I could use NFS, but I was under the impression its fairly easy to crack the security on it. Something to do with having the same user id means the password is irrelevant? Plus I may want to get some of my friends using this livecd / pxe booting "moc system" and it will be a lot easier if they can use it with their windows pcs ;)

On a seperate note, I have a question for you about samplerates. I'm using Linear sampling because my 533mhz cpu doesnt cope with sinc. I'm not sure what the difference would be sound quality wise, but I dont think I can hear it (possibly because the cpu isn't coping, if I use sincmediumquality its very choppy, sincfastest works, but maxes the cpu out and causes problems if the cpu has to do anything else, like edit the playlist even!). I've found that using Linear, I can set forcesamplerate to 96000 and my digital amp is happy using a digital output from the soundcard at that rate, and the cpu usage is around 50%. Does this mean I am "upsampling" (or is oversampling the correct term?) a 44.1khz recording to 96khz? Is it even worth bothering? What, if anything, is the theoretical benefit of this? It sounds great, but I'm not sure if I should stick to 44.1khz because most of my mp3s are recorded at that rate.

Without forcesamplerate set to _something_, anything recorded at another sample rate doesnt play through the digital output, and the 44.1khz mp3s sound "digital" - theres a kind of unnatural coloring to the sound.

I'm just not entirely sure what forcesamplerate and the various converter options do, could you expand on that a little? It would be easier to fine tune if I understood what I was changing, rather than just changing things and listening for differences.

daper

Sat, 2006-03-11 16:46

ForceSampleRate causes MOC to resample the sound to the given sample rate and then play it. If you have 44.1KHz file and ForceSampleRate set to 96KHz, MOC resamples the sound to 96KHz and sends it to the sound card in this form. I don't know how digital output works i.e. does it really output 96KHz.

In theory you will not hear any difference, no sound will be lost, 96KHz can carry sounds up to 48KHz, but since there is no sound above 22KHz in a file with 44.1KHz sample rate, you don't achive anything.

AFAIK there is one reason to resample to a higher rate: if your sound card/amplifier internally uses only one sample rate (for example 48KHz) and resamples everything else for compatibility, and its resampling quality is poor, you'd better use MOC resampling.

--
Damian Pietras - MOC developer

jefg60

Sat, 2006-03-11 17:24

thanks for all your help, and thanks for creating moc! Its working nicely now anyway.