| From: | Matt Sealey |
| Date: | 18 Apr 2001 at 21:24:04 |
| Subject: | Re: Voyager Image Decoders |
Hello Andrew
On 18-Apr-01, you wrote:
>>> And I'd agree that Voyager's ditthering is rubbish, it looks
>>> pathetic in 256 colours.
>>
>> It's a fairly standard algorithm though.
>
> So, that doesn't mean it's implemented the same,
Floyd-Steinberg is Floyd-Steinberg. Technically it should come out
identical (with the same input values). And looking at the placement
of the pixels, what's probably wrong is that IBrowse has a lame colour
selection algorithm when choosing pens. So V would pick a nice soft
grey, and IBrowse would plump for cyan. Ick.
> I mean, MP3 encoding is a standard algorithm, but different programs
> produce very different results.... :)
MP3 encoding is NOT a standard algorithm. There is a standard (the
Fraunhofer encoder) but the rest are just "similar results" encoders.
The same goes for GIF - they're LZW encoded in most cases, but you
CAN encode them WITHOUT using LZW compression (I believe there
was a graphics library.. gd? that did this quite well) to give the same
effects with not-so-small results.
>> Oh you JEST. IBrowse's dithering is absolutely ABYSMAL.
>>
>> The result?
>>
>> Well, I'll show you the result..
>>
>> http://www.niblet.co.uk/bunny.png
>
> Wow, for Voyager that is good, but on average voyagers dithering looks
> pretty crap because while it's cleaner then iB's, you get a lot of
> colour banding, especially on pictures with subtle gradients.
>
> Try it, http://mantasoft.tripod.com/
http://www.niblet.co.uk/manta.png
I circled the bits where each browser does best. So IBrowse is better
at dithering parts of the image where the colours are very similar -
white to not-so-white gradients. But the image quality, and range
of colours used, is generally better with V. Glows and faded portions
are generally of better quality.
I still think the grainy IBrowse decoding is to it's disadvantage.
> Oh, and before you ask, I'm using a *very nice* AOC 15" SVGA monitor
> :)
Then Ibrowse looks really really bad on my *very nice* Samsung 17"
SVGA monitor :)
Thanks
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