DTS to mp3 or AC3 to mp3

[killingspree]

hey guys
well since it is now possible to de/transcode DTS to mp3 i'm wondering if it would be smarter to use the DTS or the AC3 channel. The DVD i'm currently ripping is 8 mile (r1, widescreen) and contains both an AC3 5.1 and a DTS 5.1 soundtrack. i'm going for 1 CD so i can only spare 128 k for audio...

so would there be a significant difference when using a DTS for the mp3 or is the mp3 compression the limiting factor?

thanks
steVe

[DSPguru]

if you haven't tried that before, i would advise you to transcode both and then decide.

dts is surely better than ac3 for multichannel, but the 2ch downmixed ac3 could (!) sound better than the downmixed dts.
that's why i would advise you to commit a small test :D

[killingspree]

going to do that (:
we'll see what the results are (:

- i'll of course post my impression and two small samples if somebody wants to

steVe

[N_F]

I've been having the same thought as you now that dts can be transcoded to mp3/ogg, but I have no dts DVD to try it on so I'm looking forward to your conclusion (and perhaps samples).

[killingspree]

i'm currently transcoding! but what i can say for sure is that it's awefully slow. real time at best. I haven't rebooted my system though and have a few other programs like browser and outlook express running...

steVe

[killingspree]

ok... i'm done transcoding, it's really been pretty much real time.

anyway the problem is that although encoded with the exact same setting (-alt -preset 128) , there's more than a 10 Mb difference...

generally from just listening to it i do not hear a significant difference. it seems to me that the DTS mp3 sounds a bit better though, but this could just be an illusion too... or the 10 meg difference. at 92.5 and 103, it surely makes a difference...

steVe

[pacohaas]

try --preset extreme, that way you could assume that any differences in sound would be due to the downmixing and not the encoding.

alternatively you could try going to wave files, but that could end up quite large.

[killingspree]

since i'm not really good in besweet command line scripting, how do i exactly have to spell that? just -alt -preset -extreme or add the 128 afterwards?

i know i could look this up too but unfortunately i'm under quite some time pressure...

wave files is not really an option as 6 channels = 6 wave files and therefor around 6 gigs (uncompressed PCM, about 110 min)... i mean i could probably just 'decode' the LF and RF channels but i think you'll lose quite a bit of quality when encoding from those?!?

thanks for your advice
steVe

edit: is there some way to compare two mp3 files like the Compare() function in avisynth?

[DSPguru]

where are the logfiles :) ?

[killingspree]

damn it
/me stupid

i deleted the original ac3 to mp3 logfile before i started about thinking to use the dts track. it was done using gknot .28.2 if that helps.
i didn't tell the GUI to make a log file for the dts to mp3 conversation... my bad

sorry about that
steVe

[pacohaas]

just --alt-preset insane actually, that would give you the highest quality possible mp3.

You would actually only end up with 2 waves since what you want to do is look at the downmixed stereo output of either DTS or AC3, but like I said, that's still a lot of data if you don't have one of the bigger harddrives.

[NSanity]

actually... i wouldn't bother encoding it to mp3

even alt-preset extreme does stuff to the audio...

stick with wav...

hell, over a full movie for the both of them its only going to be 1gb each...

if you're encoding dvd's thats not that much anywho...