[FFmpeg-soc] [RFC] Possible jpeg2k decoder rewrite

[Jai Menon]

On 4/26/09, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Sun, Apr 26, 2009 at 04:17:48PM +0530, Jai Menon wrote:
>  > Hi,
>  >
>  > So any opinions on $subject? Quite a lot of stuff is missing in the
>  > current code (none of which is documented)
>
>  > and its also poorly
>  > structured.
>
>
> elaborate please

Well, there are just too many memcpys used to copy around data which
should be maintaned globally. Also, supporting other progression
orders requires a bunch of hacks because of bounds not being known.

>  > Also I dunno how to add support for assembling out of
>  > order tile parts etc to current code :) Suggestions welcome.
>
>
> how many j2k files use out of order tiles?

Atleast p0_10.j2k in conformance suite does. My initial aim is to get
atleast profile 0 working.

>  Why is it diffifult to support in the current code?

I'm not implying it is difficult. I just run into a few problems every
now and then which is preventing me from coming up with a clean
patchset :)
That is why I thought of asking if a rewrite is a possible solution.
Because after all, the code wasn't merged last time around so these
problems existed back then too.

Right now, the major problems (off the top of my head) are :

- only lrcp supported. should support atleast rlcp if not more.
- POC marker is not read
- component subsampling is not supported. this is required by a bunch
of profile 0 test files. right now only 1x1 supported.
- out of order tile parts.
- extra codeblock styles
- some more stuff i cant remember right now :) i should probably write
these down somewhere.


-- 
Regards,

Jai