I am using Smart Ripper and BeSure to encode AC3 files to WAV files and I'm preparing to encode into MP3. I was wondering what users on this board thought of the audio quality found in DVD's vs CD's. Would there be a huge difference in quality between a store bought CD soundtrack vs DVD aside from the added audio from the movie scenes?

I suspect the audio on DVD is heavily compressed, so it may not be as "pure" as CDDA.

It may also be optimised for home theatre, eg. with overemphasised bass?

Safer to use the CD as the master methinks.

obviously the dvd has ac3 compressed audio, which isn't as high-quality as 44khz pcm (cd audio). It does have the advantage of being 6 channel, though.

Also, for reasons that totally escape me, the audio level is much lower on DVD's.

A typical ac3(lossy) dvd stream is CBR 192kbps trying to compress 48khz/24bit, work it out.

I personally try to take the 2 Ch. pcm stream if it's available on the DVD.

It's more likely it's 448kbps

This is my understanding of the 448 stream available. I hope someone will correct me if I am wrong.

Of the 448, 192 is for left and right front. 128 for the rear channels, left and right. And 128 for the centre channel. This leaves the LFE channel. I am not sure if the lfe has bits assigned to it or is decoded from the front channel or what.

Can anyone comment on this?

448kbit sounds like a great bitrate and all, butI think it is split up, so the actual two channel track is not that great.

most swedish DVDs seem to have 384kbps, but I know finland usually have 448kbps.

AFAIK the AC3 encoder allocates the bits as needed. There are no defined bitrates for groups of channels.

Recommended bitrates are 448kbit for 5.1 and 192kbit for Stereo. Most DVDs I have use 384kbit for 5.1 though (17khz cutoff instead of 20khz with 448kbit).

AC3 is lossy compression, so there would be more quality loss if you reencode to mp3. I suggest you to demux the AC3 and you can play it with directshow filter or ac3 plugin for winamp.

If you're going to multiplex with avi(divx), you can use nandub to multiplex it. Off course it will maintain the original DVD audio quality though it's lossy. However, it's still better than reencoding it to mp3.

If I look for DVDs I would definately dig up a DTS version of it.

yup...


this sounds weard to me.. why on earth.. do you wanna mp3 it..
aac is the way to go..

(mp3 maybe OK. if you downmix to 2ch. for some..
but i imagine you lose quite a bit of quality..
perhaps purpose is for portable.. but
why not aac.. if the portable support aac..
the output will be the same ((2ch)) but the recording will
remain the same..)

((if))

Its because cds are typically compressed to sound louder on the radio. Films are mixed to reference volume levels for cinema. This reference level is fairly well below the peak so that loud events (such as explosions and what not) have more impact. This is all part of the spec i think.
Most ac3 decoders have dynamic range compression to get around this for home viewing in quiet environments.

Which is how CD's in the late 80's and early 90's were mastered. Now, they compress everything and set it at 0db SO THAT THE ENTIRE CD SOUNDS LIKE THIS

Yeah, but CD's in the late 80's/early 90's had other problems (not all, but some... digital mastering wasn't yet what it is today).

The overcompression on many recent CD's is just unbelievable to me. It ruins the sound everywhere but in an automobile or on a cheap CD player with cheap headphones. Maybe that's the point... make it sound good on cheap equipment. Then again, maybe the record companies are merely "priming" us for a new format... >_<

How do you know if a DVD audio format is AC3 or DTS? Is it mentioned on the cover?

It's good if a DVD has DTS format but the audio file bitrate is very high. Space eater.

You need a copy of something like 'Nightfly' by Donald Fagin (ex-Steely Dan) to hear a properly mastered CD. It doesn't happen these days, everything is compressed to fuck to make the single sound good on radio.

Cannot just be used a pre-amplifier to the output music without having to use dynamic compressed media? Or people on radio stations are so lazy they don't look like wasting 5 seconds in increasing the volume?

DVD (Video) May use 96khz/24bit PCM stereo audio, this is the best. Unfortunately, the rarest. Dolby Digital (AC3) is just another lossy format with support for more discrete channels, as well as DTS, only that DTS uses higher bitrates. DTS is not part of the DVD spec, it was a later "optional" addon.

Lossy audio doesn't use "bit depth", it can be interpreted closer to the original when more bit depth is available for the decoder at playback, but its "bit depth" usually goes floating point at encode time. So you can decode to any higher depth and dither back to the target bitrate of your DAC for even higher precision. I think foobar2000 does this from its 32bit processing pipe line.

And yes, i have seen too many 192kbps AC3 stereo DVDs... Just thinking they use CBR for audio makes me think twice about the quality...

They want to stay the closest to the 0db red barrier and the most time possible, without crossing it. Saturation (specially on radio) is very distorting, so, no, they can't. But i bet they wish...

Amazing how music and audio in general is aproaching "the white noise standard".

Wow. Off the net for two days and got such a response. Thanks for everyone's reply. I guess I won't be trying to replace my previous MP3 with one directly from the movie.