AC3 vs DTS vs MP3

2005-08-26 08:38:37

Hi,

I was wondering is the biggest size of a dts stream is usually worth the difference. I am in the process of ripping my Musical DVDs to pure AC3/DTS streams in order to be able to listen to them as music in 5.1 (vs as a video). dts streams are sizably bigger than ac3 streams and I was wondering if it is worth it (apart from the fact that they are usuallly not mixed the same way).

Also, can anyone tell me to what LAME bitrate a 448kbps AC3 stream could be compared. I am aware that it is hard to compare a 5.1 stream vs a stereo one, but I was wondering in terms of quality: Artifacts, transparence, these kind of things.

I know this all depends on your equipment, ears and all, but I just want a rough figure here.

Thanks

AC3 vs DTS vs MP3

Reply #1 – 2005-08-26 10:55:08

AFAIK there have been blind tests done before with DTS and DD. The results were fairly conclusive that DTS was better. This might be because it uses a much bigger bitrate (usually 768kbps, while DD maximum is 448kbps). It may be because DTS soundtracks are usually the original for the movie while DD needs to be remastered / transcoded from DTS.

I'm not sure about the comparison between DD and MP3, but I would estimate that it's comparible to APE (448kbps DD), i.e. transparent to virtually everyone.

There are some DVDs with stereo DD streams. The maximum bitrate for 2ch DD seems to be 256kbps. Perhaps you could make an accurate comparison with those.

AC3 vs DTS vs MP3

Reply #2 – 2005-08-26 11:19:02

I don't think I agree with anything you say.

Certainly saying 768kbps DTS sounds better than 448kbps AC-3 is dubious without evidence.

DTS was originally designed for ~1.5Mbps. AC-3 was originally designed for 320kbps (on films, 384kbps on DVD). I believe DTS has superiority at these bitrates, but not the ones you quoted.

It's all "IMO" - can't really say anything without fair, blind comparative tests, which the two companies involved (especially DTS) have made almost impossible.

Cheers,
David.

EDIT: AC-3 tracks are not transcoded from DTS. The "originals" i.e. masters are 6-track linear PCM, 20-24bit 48kHz. Both DTS and AC-3 are encoded from these - unless it's a rushed/bodged PAL release, where anything can happen (e.g. PAL AC-3 encoded from pitch-shifted NTSC AC-3!)

AC3 vs DTS vs MP3

Reply #3 – 2005-08-26 12:04:45

Furthermore DD is mastered to be downmixable (eg. 90° phase shift or rear chs), while DTS is not mixed in this way. So in fact it is pretty stupid to go for DTS if you want to downmix it - what a whole lot of people are tying to do. 

BTW, DD maximum is 640kbps, but this is not anymore within DVD specs.

AC3 vs DTS vs MP3

Reply #4 – 2005-08-26 17:05:06

If you looking for quality (especially with music), go for DTS. If size matter, go for ac3.
I have now a big collection of 5.1 on my hard disk. The best way is to rip it and to keep the original format (DTS or DD). Personally, when I have the choice between DTS and ac3, I go for DTS.
Problems with ac3 on music are the audio compression triggered on the centre channel and artefacts are very obvious (especially on the rears channels).