AW: [vorbis] OT: PNG and Image compression thread

[Burgwedel Friedrich]

> > Actually, PNG supports bigger paletted images then that.. Of at
> > least 4096 colors, probably more.

That is, 4096 Colors out of possible 2^48...

> If PNG supports 48 bit color, then that's actually... hm, 
> 2^48 = 281474976710656 colors. 4096 colors would be only 12 bits.

Do you know about the difference between indexed color and 'true color'? ;P
Theoretically, you might be able to have an indexed color image with 16
bits/p and 48 bit colors; you would need a palette with 2^16 entries with 48
bit each... have fun.
Indexed color at 12 bits/p seems to be fair.

Btw., I don't know if PNG supports indexed color with full alpha channel
(not indexed alpha); does anyone know?

So long
Friedrich

> -----Ursprüngliche Nachricht-----
> Von: Jaakko Lintula [mailto:crawlie at uk2.net]
> Gesendet: Montag, 2. Juli 2001 15:15
> An: vorbis at xiph.org
> Betreff: Re: [vorbis] Image compression thread
> 
> 
> On Monday 02 July 2001 14:50, Gregory Maxwell wrote:
> > On Mon, Jul 02, 2001 at 02:36:03PM +0200, Jernej Simonèiè wrote:
> > > PNG is lossless, produces smaller files than GIF, and supports
> > > grayscale images from 1 to 16 bit, paletted images from 2 to 256
> > > colors/palette entries, color images up to 48 bits, transparent
> > > color setting with paletted images, alpha channel (up to 16 bits)
> > > with others.
> > Actually, PNG supports bigger paletted images then that.. Of at
> > least 4096 colors, probably more.
> 
> If PNG supports 48 bit color, then that's actually... hm, 
> 2^48 = 281474976710656 colors. 4096 colors would be only 12 bits.
> 
> --- >8 ----
> List archives:  http://www.xiph.org/archives/
> Ogg project homepage: http://www.xiph.org/ogg/
> To unsubscribe from this list, send a message to 
> 'vorbis-request at xiph.org'
> containing only the word 'unsubscribe' in the body.  No 
> subject is needed.
> Unsubscribe messages sent to the list will be ignored/filtered.
> 

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.