What are packed and unpacked files?

[Burkeville]

Hello friends,
What are packed and unpacked files?

I tried to send some unpacked to a mastering place a few years ago and they weren't able to open them, so they wound up using my 16 bit reference cds! (that was a album for Rounder/MCA)
Now I have another big record going out the door and I would like to find out what unpacked means.

Thank you

[Bob L]

When creating 20 or 24 bit files, the files can be stored in different formats.

The packed format actually stores the data in 3 bytes per sample, which allows for a max of 24 bits.

The unpacked format stores the data in a full DWORD (4 bytes per sample), which allows for a max of 32 bits, and therefore the filesize is actually larger.

The unpacked format was something I created as an extension into the future when the bit resolution grows beyond 24 bits. It can sometimes also possibly improve performance due to the fact that our current Pc's access data in DWORD chunks and the packed format requires multiple register shifts to compact and expand the data into the odd size 3 byte format, which translates into more internal manipulation to access each sample.

In most situations the difference may not be noticable.

For compatibility with other 24 bit wav files in most other software, you should use the default packed format.

Bob L

[Burkeville]

Thanks Bob,
There are universities filled with things I don't know about.
I searched for this in the manual and couldn't find it.

[Bob L]

I'm not sure if the packed and unpacked info was ever put in the manual...

I'll look into it.

Bob L