Re: [gentoo-user] merging or fitting images together

[Michael Mol]

On Mon, May 21, 2012 at 12:57 PM, Paul Hartman
<paul.hartman+gentoo@×××××.com> wrote:
> On Mon, May 21, 2012 at 11:31 AM, Michael Mol <mikemol@×××××.com> wrote:
>>
>> I'm seriously wondering if there might not be something broken with
>> the .jpeg files I'm spitting out. That laptop (saffron) is in the
>> middle of an overdue emerge --update --deep --newuse @world, though.
>> (And I saw it was complaining about 19 blockers...) It may be overdue
>> for a depclean and some other maintenance. I haven't tweaked things
>> much, as it's my last functioning Gentoo box until I get kaylee and
>> inara fixed.
>
> It looks like the file uses arithmetic coding, which has legal
> restrictions (patents, licensing, blah), which means many jpeg
> implementations do not support it. That probably is why it works in
> some places and not in others. You should pretty much always use
> Huffman coding instead of Arithmetic coding if you're using the images
> on the internet or sharing them with others. The image quality is not
> affected by this choice, only the way the data is stored in the file.
> The file size will be slightly larger using Huffman, but in most cases
> only barely larger.

I'm familiar with the difference between Huffman and arithmetic[1]. I
don't recall seeing any options for managing it, though. I'd have to
check to find out what USE flags I've got enabled that might be
involved. Also surprising that Windows 7 won't process it.

[1] Side effect of having a crazy compression geek for a friend and
coworker. I think he finally got around to trying my suggestion of
saving off the deflate window state for seekable .tar.gz files.
-- 
:wq