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Subject: Re: Hi & Wavpack broken?

Re: Hi & Wavpack broken?

From: David Bryant <dbryant_at_impulse.net>
Date: 2006-02-11

I generally *am* concerned about backwards compatibility, but the older
WavPack formats were not really designed for embedded decoding. Hell, when
WavPack 1.0 was released, a desktop PC couldn't even decode them in
realtime!

I started WavPack 4.0 essentially from scratch, and designed it from the
ground up to be hardware friendly. While I would never release a winamp
plugin or Audition filter that could not handle a pre-4.0 file, handling
them in embedded applications is optional (as is handling correction files
or mutichannel files) and that's why these were not included in the "tiny"
decoder.

Handling older WavPack files on RockBox would certainly be possible, but it
would be a pretty big job and the codec size would jump considerably (there
were lots of variations and special cases over the years) and
hand-optimizing it would be a chore. And, when it was done, those files
would still not be able to seek or resume, or recover from an error. It
ain't gonna happen... :)

However, I agree that it should not blow up attempting to play one. The way
it should work is the codec scans for up to 1 mb into the file for a valid
WavPack 4.0 header. If it doesn't fine one it gives up and returns an error.
But it might take too long to do that, or something. I suppose that I could
quickly check for a pre-4.0 file, and bail out right away. That still would
not help the case where some random file was given a .wv extension, but it
would handle the first case.

BTW, the first thing I'm going to work on is to get "high" mode WavPack
files playing on the iPod; with any luck it should be just a few days away.

----- Original Message -----

From: "gl" <gl@ntlworld.com>
To: "Rockbox development" <rockbox-dev@cool.haxx.se>
Sent: Friday, February 10, 2006 8:06 AM
Subject: Re: Hi & Wavpack broken?

>
> > Then small wonder, our decoder (a modified version of the tiny decoder
> > from
> > wavpack.com) does not support pre-4.0 files. You'll have to ask David
> > Bryant
> > about how possible it is to support these files.
>
> I'll check with him. He likes to stay backwards compatible. In the
> meantime, those files should be refused. Some seem to be, but others try
to
> play regardless and cause the problem.
>
> > And BTW, 48kHz SPDIF playback is not possible, only 44100/22050/11025.
>
> Right, but 48k input is possible as the clock is external, correct? What
> about 24bit digital in?
> --
> gl
>
>
Received on Sat Feb 11 06:53:03 2006


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