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Tom and Don el al.,

This argument against compression has been around as long as there has been data compression and it doesn't really hold up. Data corruption can corrupt any data, compressed or uncompressed. Data corruption is an argument *for* backing things up or running checksums, not *against* compression.

Lossless compression is so widely used now that it isn't an issue to argue over anymore. Every PNG and GIF file on the internet is compressed losslessly and we aren't worrying about corruption there. TIFF has LZW compression built in and it is the archival image standard. The issue is that it has to be implemented correctly and widely supported. I don't think FLAC is there yet. I'll be interested in investigating mpg4als which Bob Olhsson mentioned.

Off the top of my head I'd say these would be the basic requirements for a lossless compressed format to take off in the audio world and supplant wav as the standard format for archiving:

1) Files should inflate when opened in *all* the commonly used audio editing tools (no need for helper aps). Can you imagine if you had to decompress a jpeg in a helper app before opening it in Photoshop?
2) Transparent support of wav/BWF metadata both on inflate and on deflate. In other words, your metadata doesn't get screwed up when you open a file in another app, make changes, and then save as compressed again.
3) Files play back on/in *all* standard consumer playback hardware/software (itunes, ipods, real, winamp, etc)

Anything come close yet?

David Seubert

Don Cox wrote:
On 27/10/06, Tom Fine wrote:
A couple of points on this:

1. even if a format is truly lossless vis-a-vis audio quality (which
is perfectly achievable through standard data-compression techniques),
I would argue that it adds some risk and complexity to your digital
archive. The reason is that compressed data, by its very nature, is
more vulnerable to corruption and complete loss if a smaller area of a
storage medium is damaged.

I agree with this. I can't see that the risk is worth it for a space saving of up to 50%, now that storage media are so big.

In a plain WAV or AIFF file, if one bit is corrupt, it will just give a
small click (which can be repaired), and has no effect on any other
samples. In a compressed file, any fault can affect a whole sequence of
samples, or even make the file unreadable from that point to the end.

And audio files are big, so there is more chance of one file developing
a fault somewhere than in the traditional compressed text or GIF files.


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