Re: [LAD] new lossless/lossy audio compressor

It probably would suffer some, but it would still be better than raw. The MSBs should compress
well, just as if it were reduced to 16-bit; the frequencies should not change. The LSBs would be
pretty erratic though; like trying to compress noise. But you don't know unless you test.

Can wav files store 32b float? I have never worked with 32b audio data, but I have worked with 32b
sensor data many times. If so, this may be a trivial thing to test and it should involve very few
code changes.

--- Paul Winkler <pw_lists@email-addr-hidden> wrote:

> Could do that... I wonder if the compression ratio would suffer,
> though. Just a hunch.
>
> -PW
>
> On Wed, Jul 25, 2007 at 01:37:18PM -0700, Gregory Alan Hildstrom wrote:
> > The JasPer library documentation states that a single image component can be from 1 to 16 bits
> per
> > sample, so not directly. 24-bit color images are actually treated as 3 8-bit components: like
> one
> > red component, one green component, and one blue component.
> >
> > For lossless compression, we could easily place the most significant 16 bits in the first
> image
> > component and place the least significant 16 bits in a second image component of each frame.
> It
> > should also be possible to code something up that does the same sort of 16-bit splitting into
> 2
> > flac files. -Greg
> >
> > --- Paul Winkler <pw_lists@email-addr-hidden> wrote:
> >
> > > Pretty cool. Does JPEG 2000 handle float data?
> > >
> > > I'd love to be able to write an archive script for Ardour sessions
> > > that compresses the audio data losslessly, but FLAC won't do it.
> > >
> > >
> > > -PW
> > >
> > > On Wed, Jul 25, 2007 at 12:47:16PM -0700, Gregory Alan Hildstrom wrote:
> > > > Hello. I just finished writing and documenting a new lossless and lossy audio codec called
> > > > j2kaudio. It uses the wavelet compression in JPEG 2000 to transcode audio wav data to and
> from
> > > j2a
> > > > files. I have not written any sort of media player plugin yet; more testing and file
> format
> > > > refinement are necessary first.
> > > >
> > > > I tested with 44100Hz, 16-bit, stereo CD-quality wav files, but it also supports other
> sample
> > > > rates, precisions, and channel numbers.
> > > >
> > > > I tested against flac, lpac, shorten, and monkey's audio for lossless encoding. j2kaudio
> beat
> > > the
> > > > nearest competition by over 10%.
> > > >
> > > > If anyone is motivated to test some additional songs, provide me with additional test
> data, or
> > > > suggest another untested codec, please let me know.
> > > >
> > > > http://geocities.com/hildstrom/projects/j2kaudio/index.html
> > > >
> > > > Let me know what you think. Thanks. -Greg
> > > >
> > > >
> > > > Gregory Alan Hildstrom
> > > > Secure Systems Engineer - Trusted Computer Solutions
> > > > trustedcs.com
> > > > ghildstrom@email-addr-hidden
> > > > Software Engineer - Hildstrom Engineering
> > > > geocities.com/hildstrom
> > > > hildstrom@email-addr-hidden
> > > > Mobile:(210)413-6082
> > > > Fax:(210)599-0469
> > > > Office:(210)340-3151x117
> > > > _______________________________________________
> > > > Linux-audio-dev mailing list
> > > > Linux-audio-dev@email-addr-hidden
> > > > http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev
> > >
> > > --
> > >
> > > Paul Winkler
> > > http://www.slinkp.com
> > > _______________________________________________
> > > Linux-audio-dev mailing list
> > > Linux-audio-dev@email-addr-hidden
> > > http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev
> > >
> >
> > _______________________________________________
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> > Linux-audio-dev@email-addr-hidden
> > http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev
>
> --
>
> Paul Winkler
> http://www.slinkp.com
> _______________________________________________
> Linux-audio-dev mailing list
> Linux-audio-dev@email-addr-hidden
> http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev
>

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Received on Thu Jul 26 00:15:07 2007