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6 Channel MP3

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RushMaster
Member


Joined: 24 Feb 2007
Location: Canada

Post Posted: Oct 26, 2007 14:32 Posts Comp View users profile Send private message Reply with quote

Is this possible? Never really thought about it before because I assumed that if I were to burn the mp3 files to disc, it would just come out as 2 channel audio during the conversion process anyways.

What I'm trying to do is, I have a DVD that has a music album on it in 6 channel ac3 files of course, so I converted THOSE files to 6 channel wav files, but after that process im left with 2.02GB worth of music files, which of course won't fit on CD, so I figure if I convert the files now to 6 channel mp3 (if that's even possible) then perhaps I could get the files small enough to fit on a regular CD, although there will be some quality loss. That much I'm aware of.

So if anyone knows of any software that can help me convert ac3 files to a small enough format to fit on disc and keep the 6 channels, it would be appreciated.


Cornucopia
Patently Pending


Joined: 22 Oct 2001
Location: E-Cnt. IL, USA (AGAIN!)

Post Posted: Oct 26, 2007 15:21 Posts Comp View users profile Send private message Reply with quote

Your choices (from what I can see):

1. AC3-WAV encoding (AC3 encapsulated in WAV header, with silence padding to maintain CD bitrates)--> AudioCD burning --> decoding on PC or on settop DVD player with bitstream out to AC3-capable decoding amp. So-called "AC3-CD". See threads that refer to this.

2. DTS-WAV encoding (same as above, but substitute DTS for AC3). So called "DTS-CD". See threads that refer to this.

3. MPEG1 Layer2 Multichannel encoding (using something like Hypercube Transcoder) --> authoring/burning as SVCD or DVD --> decoding on PC or on settop DVD player with bitstream out to MPEG Multichannel-capable decoding amp.

4. MPEG1 Layer3 "Surround" encoding (fairly new, uses proprietary software licensed from Fraunhoeffer or Philips). Burn as data to disc, decoding only on PC.

5. Some other more obscure format, decodable only on PC.

Scott
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aedipuss
aBigMeanie


Joined: 25 Oct 2005
Location: 666th portal

Post Posted: Oct 26, 2007 15:23 Posts Comp View users profile Send private message Reply with quote

search for the fraunhofer mp3 surround encoder. it's free. the problem is no cd players support playback in mp3 surround that i'm aware of. it will still playback in stereo if not supported.
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jman98
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Joined: 08 Oct 2004
Location: Freedonia

Post Posted: Oct 26, 2007 21:11 Posts Comp View users profile Send private message Reply with quote

To followup on Cornucopia's excellent post...
AC3-CD or DTS-CD would be your best choices. It is essentially impossible to find any device in North America that is capable of correctly decoding MPEG1 layer 2 multichannel sound. It may be impossible in Europe as well now for all I know. Philips has abandoned the format and nothing outside of MAYBE (heavy emphasis on that word) PCs is now able to correctly play them. You'll get stereo playback instead on almost all devices because MPEG1 layer 2 multichannel is compatible with stereo playback and stereo playback of this audio format is all anything seems to support any more. I've never seen any devices except PCs that can play back MPEG1 layer 3 (MP3) surround files. MP3 surround files are more theoretically possible than practical and while I applaud Fraunhoffer, etc. for the format, nobody seems to be interested in it. AC3-CD and DTS-CD are both able to be played back on a wide variety of devices. Basically if you have a DVD player and an amp that supports decoding AC3 and DTS, they will both work for you. PC playback is no problem either. Do note that audio CD only players, such as in cars, cannot play back these discs. AC3-CD is really your best bet as converting to DTS-CD will require you to encode to DTS and that is lossy. You might notice some sound quality loss as a result of the encode to DTS. It's hard to sayk, but it's possible. AC3-CDs are a little tricky to make. Do a web search for the info. I have one as a demo disc that I downloaded from some web site a few years ago. but I didn't do the conversion to AC3 and I don't know what programs are needed to get from AC3 to AC3-WAV so that it can be burned to audio CD.


Cornucopia
Patently Pending


Joined: 22 Oct 2001
Location: E-Cnt. IL, USA (AGAIN!)

Post Posted: Oct 27, 2007 00:51 Posts Comp View users profile Send private message Reply with quote

Note: You'll probably have to re-encode in ANY event.
AC3-WAV is NOT going to be identical to a standard AC3 file.
1st, you've got different sample rates (48k expected from DVD, 44.1k expected for CD).
2nd, you've got to space/pad the bitstream so the resultant "WAV" file is exactly your standard stereo CD audio bitrate (1,411,200 bps).

Apps that USED to do this would be SoftEncode (1st pass-decode to 6ch wav, Do SRC in another app, 2nd pass-encode to AC3-WAV).
Minnetonka probably has an appropriate AC3 or DTS encoder currently...

Scott
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ricardouk
Member


Joined: 15 Mar 2005
Location: PORTUGAL

Post Posted: Oct 27, 2007 10:11 Posts Comp View users profile Send private message Reply with quote

Aud-X

i converted an ac3 5.1 speaker setup test file with aud x, and when playing it back on my home cinema the mp3 file played correctly.

Dont remember much of the details but it works, before thefraunhofer mp3 surround encoder apperaed this was the software "everyone " was talking.
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Nelson37
Member


Joined: 14 Aug 2001

Post Posted: Oct 27, 2007 13:32 Posts Comp View users profile Send private message Reply with quote

If an AC3-WAV is what I am thinking it is, like an SPDIF capture, then BeSweet will make these. I think they call it 5.1 Wave, or similar. Exactly like a 5.1 SPDIF capture. I have never tried playing one of these files directly thru SPDIF as output to my amp as I read the volume could be too high and damage equipment.

Hasn't been too long ago my local wholesale club had a Phillips HT package, this does handle multi-channel MPG. But this capability is so rare that I would not advise using it. Am making an Mpg 5.1 SVCD just for fun, but just once.


redwudz
Mod Neophyte


Joined: 07 Sep 2002
Location: AZ, USA

Post Posted: Oct 27, 2007 13:46 Posts Comp View users profile Send private message Reply with quote

Here's a link to the Aud-x VirtualDub Mod program that is one fairly easy method of MP3 surround sound. http://www.aud-x.com/index.php?option=com_remository&Itemid=3 ... ilecatid=3

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