Wav compression? 90 minutes of audio to 700MB (80 min) CD

[chulew]

How can I do this and keep the CD compatible with standard CD players? MP3 format and 800MB cds are out of the question. Can a wav be compressed without changing the format? Maybe resampling or time scaling? I don't mind some loss of quality to gain 10 minutes.

[Cornucopia]

If you're talking about a Standard Audio CD, the specs are clear and unchangeable:

16bit, 44100Hz, stereo, uncompressed LPCM

and size is measured by time

So, a 90 min. sound clip would require a 90/99 min. CD to be able to burn all on one disc.

On audio CD's, there is NO compression allowed.

Since you've already ruled out longer CD's (with or without overburning), and compressed file DATA cd's or (S)VCDs, your remaining choices are limited to just 2:

1. Split onto 2 discs.
2. Time-compress to <80 min.

The standard wave editors (Audacity, Goldwave, Audition/CoolEdit, ProTools, Soundforge, etc) can do either/both of these.

Scott

[chulew]

Ok, and by "time-compress" you mean essentially speeding up the playback while recording 80 minutes in real time with the standard specs right? That would be fine. The audio would be about 11.1% faster than the original.

I have installed Audacity but I'm sure there is are more technical ingredients to "time compression" since there is not menu option for that particular term (I didnt' expect to find it). What process steps am I looking for?

[chulew]

I think I found it. I'm exporting the new wav now. I think it is under NEW TIME TRACK which gie me the option of setting new SPEED LIMIT bounds as %.

[chulew]

Ok its CHANGE TEMPO from the EFFECT menu.

[Cornucopia]

Not familiar enough with Audacity to have used its TC capabilities (I normally use Audition/CoolEdit on PC and ProTools on Mac).

Choice you're going to have to make is: Will this speeding up make the enjoyment of the playback unacceptable? 11% is alot! If it were me, I'd use 2 discs unless the material was somebody's technical speech (and then, I'd probably pre-edit before TC, so the change would only be ~<4%). Music usually sounds crappy when sped up by that much.

Scott

[chulew]

Bible prophecy seminar. Might help keep some folks from dozing actually.

[jman98]

chulew - Why don't you just search for 90 minute CD-Rs and burn the files that way? Most burners can burn 90 minute CD-Rs correctly and most devices can play them without problems. I have several audio CDs that are on 90 minute CD-Rs of varying lengths from about 83 minutes to 89 or so and they play fine. I don't think an 11% speed up is a very good idea, but it's your decision.

[SingSing]

Blame Scott.

[Cornucopia]

Bible prophecy seminar. Might help keep some folks from dozing actually.

Oh, that's a good one!

Maybe you could have it start out normal, but make it speed up more and more towards the end... (you know, rushing towards doomsday)

*Note: The original CD-R standard was 63 min, extended to 74 min. extended again (by some manufacturers) to 80 min., and extended by a small few manufacturers to 90 and 99 min. (the max possible addressable for CD). I disagree with jman98 about 90/99 capacity discs being so compatible. In my experience with many clients, that hasn't been the case. I avoid them if at all possible.

I've done a number of "Financial Planning Seminar" CD series, and even a "Arborist Manual" series (in SPANISH), where I TC'd up to ~10% in spots, so it's possible for voice. Once again, I did some judicious pre-editing.

Scott

>>>>>>>
???SingSing???

[SLK001]

Cool Edit gives you the option of compressing the time while maintaining the pitch.

[hech54]

I use LG burners(4040B, 4167B) with Prassi Ones to burn my 90 minute CD-R's(red TDK 800MB)...so far they play in everything I've tried. LG's are rare in one way...they read 90 CD-R's as 90 minutes available to burn....no overburning foolishness required.

[olyteddy]

Radio Shack used to sell a Casette player that could speed speech up (up to double speed), without changing the pitch. I recall reading a study where comprehension and retention actually went up when speech was time compressed like this. Google 'time compression and comprehension' and see.

[mike47]

record/convert it to mono!
then you will fit in on a cd with room to spare

[Ai Haibara]

record/convert it to mono!
then you will fit in on a cd with room to spare

Not on an audio CD. See Cornucopia's first post above.

[mike47]

stereo audio requires aprox 10Mb per stereo minute, so 90 mins of stereo audio is gonna be about 900MB.
make it in to mono it will come out at about 450/500mb which will burn on a regular cdr

[Ai Haibara]

But as Cornucopia pointed out, you can't have mono audio on an audio CD, as far as I know. If you're going to record it as data, no problem.

[mike47]

trust me you can, I do it on a daily basis. any audio cd burning software will just see a smaller wav/aiff file. Its not compression, its just a smaller file *yawns*
put any stereo audio file in to the likes of cooledit or audacity, mono it, export it and compare the file size.
FYI I use 'deepburner' for audio CDs.

[AlanHK]

I don't know if just making it mono will make it fit, but that gave me a similar idea that I know will work:

Make it mono. Split into two 45 min tracks. Make a 45 min stereo track with the first track as left, the second as right. So playing it will be a bit like a C90 cassette tape, start with the balance 100% left, after the first half is done replay with 100% right.

This trick is used to get two soundtracks on VCDs. I have a lot of Hong Kong VCDs where left is Cantonese, right is Mandarin or sometimes English. The remotes for VCDs and DVDs here let you switch channels with a click or two.

You might have a brief announcement in normal stereo at the beginning (a separate track that can be skipped easily) to explain how to set it up.

[mike47]

you can burn a mono audio file to cd. Mono audio files are half the size of stereo audio files in WAV and AIFF.

[AlanHK]

you can burn a mono audio file to cd. Mono audio files are half the size of stereo audio files in WAV and AIFF.

On your PC, yes. But what happens when you burn them as an audio CD?
For one thing, I believe it's impossible to go over 100 minutes.

I haven't experimented myself, perhaps it does work.

[mike47]

On any computer a mono audio file (WAV/AIFF)will be aproximately half the file size of a stereo file.
Any audio CD burning software will see a smaller file and burn it, it will not use the same amount of disc space as a larger stereo file, thus a peice of audio that is, lets say 60 minutes in stereo will require aprox 600Mb of disc space, if u collapse the same audio file to mono ( a single audio track) it will reduce in size to something like 300Mb.
The burning software will just burn the audio in the normal way, but it will be a smaller file thus allowing you to burn a larger chunk of audio. I didnt say anything about going up to a hundred minutes, the guy has 90 minutes of audio, collapse that to mono it should come out at about 450/500Mb. That will burn to a 650Mb CDR!

[chulew]

Wow! Some really innovative ideas! I got away with a slight speed increase this time.

[mike47]

He He He

[jagabo]

the guy has 90 minutes of audio, collapse that to mono it should come out at about 450/500Mb. That will burn to a 650Mb CDR!

On a data CD, not an audio CD.

As Conucopia point out earlier, audio CD supports one format and one format only: 16bit, 44100Hz, stereo, uncompressed LPCM. Your mono WAV file will end up as dual mono on the audio CD (ie, left and right will have the exact same data), or you'll get the audio on one channel and the other will be silent. Neither case will let you put more playing time on the audio CD.

[AlanHK]

On any computer a mono audio file (WAV/AIFF)will be aproximately half the file size of a stereo file.

I know the files are different. But computer data is not the same as audio CD data. It's NOT a wav file. Have you actually tried this? Has anyone? I don't have any spare CDRs lying about at the moment or I would.

[mike47]

sorry to sound rude, but if u BOTHERED to read my answer you would see that I wrote

"Any audio cd burning software will just see a smaller wav/aiff file. Its not compression, its just a smaller file "

wav files or aiff files are burnt to cd by the authoring program irrespective of thier size (as long as it will fit the medium) stereo or mono.
PLEASE READ MY THREAD THOROUGHLY BEFORE YOU SAY IT WONT WORK
yes it does work. you can burn mono files to cd and they take up roughly half the space of a stereo file.

I DO IT ON A DAILY BASIS!

STOP trying to discredit me until you have done it . mono files take up less space and subsequently you get more audio on to a CDR

the cd burning program does not "look" at a mono wav or aiff file and then burn it to the same amount of space as a larger stereo file.

[Cornucopia]

This is silly.

You got a computer stereo WAV file of 800MB. Too big to fit one one AudioCD. You mix it to mono and now it's 400MB. But it's still a WAV file on a PC. It's NOT an AudioCD.

AudioCD's DON'T have WAV files, they have 2channel LPCM tracks. End of Story.

Like said before, if you take your 400MB mono WAV file and try to burn it to AudioCD (not DataCD--OP never wanted that), you will get one of these:

1. Burn program saying it isn't compliant and crashing (not likely)
2. Burn program saying it isn't compliant and asking to convert to compliant file (Dual Mono = 800MB again) and then having it be too big to fit on one AudioCD and stopping.
3. Burn program not telling you anything, but converting to DualMono automatically, yet STILL being too big to fit onto one AudioCD and stopping.
4. Burn program doing the same as #3, but automatically (or maybe asking 1st) splitting the file in 2 for burning onto 2 AudioCD's (back where we started in the original response).


It will never burn half as much, it will never burn only 1 channel--or even put silence on 1 of the 2 channels. To do that would require an audio editing app where you remix the mono to 1 channel of a new stereo file and then apply digital silence to the other and saving as a new stereo WAV (of 800MB no less). Doing the other thing with folding over the 2nd half of the show into the 2nd channel does save the space (I've suggested this before myself), but you got to understand, it's VERY NON-STANDARD. There are many players/soundsystems where you CAN'T just listen to 1 channel, and that would completely defeat the purpose.

mike47, try to come up with something constructive within the bounds of the OP's requirements (not yours)...

Scott

[mike47]

This is silly.

You got a computer stereo WAV file of 800MB. Too big to fit one one AudioCD. You mix it to mono and now it's 400MB. But it's still a WAV file on a PC. It's NOT an AudioCD.

AudioCD's DON'T have WAV files, they have 2channel LPCM tracks. End of Story.

Like said before, if you take your 400MB mono WAV file and try to burn it to AudioCD (not DataCD--OP never wanted that), you will get one of these:

1. Burn program saying it isn't compliant and crashing (not likely)
2. Burn program saying it isn't compliant and asking to convert to compliant file (Dual Mono = 800MB again) and then having it be too big to fit on one AudioCD and stopping.
3. Burn program not telling you anything, but converting to DualMono automatically, yet STILL being too big to fit onto one AudioCD and stopping.
4. Burn program doing the same as #3, but automatically (or maybe asking 1st) splitting the file in 2 for burning onto 2 AudioCD's (back where we started in the original response).


It will never burn half as much, it will never burn only 1 channel--or even put silence on 1 of the 2 channels. To do that would require an audio editing app where you remix the mono to 1 channel of a new stereo file and then apply digital silence to the other and saving as a new stereo WAV (of 800MB no less). Doing the other thing with folding over the 2nd half of the show into the 2nd channel does save the space (I've suggested this before myself), but you got to understand, it's VERY NON-STANDARD. There are many players/soundsystems where you CAN'T just listen to 1 channel, and that would completely defeat the purpose.

mike47, try to come up with something constructive within the bounds of the OP's requirements (not yours)...

Scott

as i said , i do this on a daily basis ......it works, i use deepburner and get twice as much audio on a cd using single track mono aiff files out of cubase. it plays as an audio cd not a data cd
wotver.

[chulew]

mike47, I guess the question is do your mono cds play on a standard audio cd player. If they do, then it works. If not, then it just works when played on a PC or higher compatability player.