mellotron samples

[Jeremy Brookes]

> <<Something that works pretty well is to delta encode the PCM
> (first output
> sample in each channel is
> actual 16-bit valueof first input sampel, all following output samples
> are the difference between the
> corresponding input sample and the previous input sample) and then use
> ZIP on it.  The delta encoded
> values have much more redundancy in the high byte than the original
> source.  Of course, there is no
> file format that I know that directly supports this.>>
>
> Both EMagic and Waves, Inc.  have some kind of proprietary file
> compression
> software for use with audio files.  They are probably using some
> variation of
> the above process.  I think they both claim about 60% file size
> reduction.  I
> don't think either of the formats is in very wide use - most
> professionals
> don't want to bother with another step in their archiving
> process, and CDR's
> are so cheap these days!

the problem with this approach to audio encoding formats is that it's more
difficult to start playing the audio file part way through - you have to run
from the start (at one would hope greater than real time) to get to the
middle. No instantaneous playback from the file without decoding it into
memory first.

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