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

[Michael Niedermayer]

On Sun, Jun 14, 2009 at 04:51:36PM +0000, Jai Menon wrote:
> On Wed, Jun 10, 2009 at 11:45 AM, Michael Niedermayer<michaelni at gmx.at> wrote:
> > On Tue, Jun 09, 2009 at 03:25:52PM +0000, Jai Menon wrote:
> >> On Sat, May 2, 2009 at 8:23 PM, Michael Niedermayer<michaelni at gmx.at> wrote:
> >> > On Sun, May 03, 2009 at 12:56:02AM +0530, Jai Menon wrote:
> >> >> On 4/26/09, Michael Niedermayer <michaelni at gmx.at> wrote:
> >> >> > On Sun, Apr 26, 2009 at 05:47:11PM +0530, Jai Menon wrote:
> >> >> >  > On 4/26/09, Michael Niedermayer <michaelni at gmx.at> wrote:
> >> >> >  > > On Sun, Apr 26, 2009 at 04:17:48PM +0530, Jai Menon wrote:
> 
> [...]
> 
> >> I think I have narrowed the problem down to the tagtree decoding code,
> >> but don't know what to fix and where to fix.
> >
> > in the most generic sense you should have some difference between some
> > reference implementation and our decoder
> > whereever that is there is prior code that can be tested for being
> > different or not.
> >
> > if you tell us what variable with what value in what line of our code differs
> > from what in what line of some reference we might be able to help ...
> 
> I tried rewriting that part from scratch based on the spec, and still
> get the same problems. So maybe my assumption was wrong.
> 
> The file i'm using is file
> http://samples.mplayerhq.hu/jpeg2000/j2kp4files_v1_2.zip/testfiles_jp2/file3.jp2
> 
> Here is jasper's output for that file:
> 
> packet size is 278
> packet size is 58
> packet size is 61
> packet size is 785
> packet size is 162
> packet size is 160
> packet size is 2883
> packet size is 567
> packet size is 533
> packet size is 10259
> packet size is 2056
> packet size is 1905
> packet size is 36007
> packet size is 7836
> packet size is 7421
> packet size is 111139
> packet size is 30613
> packet size is 29299
> no.  of packets 18
> 
> And here is what our decoder says :
> 
> size of packet is 278
> size of packet is 58
> size of packet is 61
> size of packet is 785
> size of packet is 162
> size of packet is 160
> size of packet is 2883
> size of packet is 567
> size of packet is 533
> size of packet is 10259
> size of packet is 1
> ^^^^^^^^^^^^^^^^^^^^^    <------- Packets arent read correctly from here on
> size of packet is 21
> size of packet is 1
> size of packet is 31
> size of packet is 1
> size of packet is 164
> size of packet is 35
> size of packet is 42
> no.  of packets 18
> 
> I'll continue looking into this.

could you post the diff to the C files you used to get that output?

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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