Audio compression

[irondagger]

Does anyone know how to compress a 1 gig .wav file.

[KpeX]

Lol. That's funny.

I know one or two ways. Rar, zip, flac, wavpack, aac, vorbis, ac3, dts, mp3, mp2, mp1, many others, your choice.

[LigH]

Yeah - depends at least on the question if you want to archive it losslessly, or want to make a psycho-acoustically compressed audio stream for a movie (where it furthermore depends on which kind of material you are planning: AVI, SVCD, DVD...).

So with a little further help from you, it will be much easier to help you more properly.

Anyway: Welcome as new member of this board.

[Lagoon]

KpeX, what is MP1 ? :D Never heard of it.

[LigH]

MP1 = MPEG Version 1 Audio Layer 1.
MP2 = MPEG Version 1 Audio Layer 2.
MP3 = MPEG Version 1 Audio Layer 3.

MPA ~ MPEG Audio. Usually Layer 2, but not really for sure... ;)

[Lagoon]

I kinda guessed it was MPEG-1 Layer I, but I didn't know this audio was used anywhere and AFAIK there is no encoder for it :confused:

[irondagger]

It was a audio stream for a movie. It is the audio file DVD2AVI made when I told it to save project.

[KpeX]

@lagoon

There are a few very old encoders around if you know where to look (http://www.rjamorim.com/rrw/).

@irondaggers

There are many audio compression formats. Pick one, use the search, but we can't help you with these sorts of vague questions.

[Pyscrow]

Originally posted by irondagger
Does anyone know how to compress a 1 gig .wav file.

Apart from all the other comments to do with file compression I assume you want to increase the compression of the waveform within the file?

I use Cool Edit Pro to do mine, thats a bit pricey though, As I have used this for years I dont know of any freeware or cheap programs that handle audio compression though.

When you do get something to compress it for you, be very careful if you go past about 80%, as distortion is likely! (Unless you want your sound track to sound like alvin and the chipmunks)

[Sycho]

MPA is MPEG AUDIO II LAYER I, and it has a MPEG AUDIO I LAYER II stream so it is backwards compatible

[LigH]

How can you be so sure? Don't you know that a filename extension doesn't mean anything? It is just a hint for humans to guess what might be inside, and a technology for Windows to assign a program to open such a document. But there is no official specification that reserves one filename extension exclusively to only one purpose, no law can force me not to change the extension of a file as I like it.

"MPA" is a hint to "MPEG Audio". Nothing more. Such a file is allowed to contain MPEG Version 2 Audio. But it might also just contain MPEG Version 1 Audio without any MPEG V2 extension blocks inside.

Unfortunately, there are programs which mask out files with a specific extension to be displayed in a "file open dialog" only, or even being loaded. So for example, some tools expect a file to be called "*.mpeg" to be loaded as video stream, although more exactly it would have been called "*.m2v".

"*.mpa" may be MPEG Version 1 or 2 Audio, Layer 1 or 2; but judging only from the filename extension, I would bet not even one cent on its content, I always would rather start to analyze it instead, if I really want to be sure. The first person to blame for unnecessarily renaming a file is the programmer of a tool that stubbornly creates or opens only files with one specific extension.
__

@ irondagger:

I guess I know your mistake: Your DVD2AVI was set up to decode an audio stream to WAV during saving the project file.

If you set it up to demux audio streams instead, DVD2AVI will save it in its original, compressed form (probably as AC3 or MPA file, depends on your DVD).

And to repeat KpeX: Please, help us helping you - by telling us as verbosely as possible any probably necessary detail: Which audio streams are in your DVD (your ripper will tell you), which stream would you like to get, which kind of file format shall your copy be afterwards...

[Sycho]

Originally posted by LigH
How can you be so sure? *.mpa can hold any mpeg audio stream, but is intened for audio II layer I