[FFmpeg-devel] JPEG2000 decoder

[rukhsana afroz]

Hi Michael,

On Tue, May 24, 2011 at 1:10 AM, rukhsana afroz <rukhsana.afroz at gmail.com>wrote:

> Hi Michael,
>
> On Fri, May 20, 2011 at 10:49 PM, rukhsana afroz <rukhsana.afroz at gmail.com
> > wrote:
>
>> Hi Michael,
>>
>>
>> On Thu, May 19, 2011 at 3:38 PM, rukhsana afroz <rukhsana.afroz at gmail.com
>> > wrote:
>>
>>>
>>>
>>> On Thu, May 19, 2011 at 3:32 PM, rukhsana afroz <
>>> rukhsana.afroz at gmail.com> wrote:
>>>
>>>> Hi Michael,
>>>>
>>>>
>>>> On Sun, May 15, 2011 at 5:00 PM, Michael Niedermayer <michaelni at gmx.at>wrote:
>>>>
>>>>>
>>>>> We will have to implement multiple codeword segments.
>>>>>
>>>>> Also sofar, good work!
>>>>>
>>>>>
>>>> Sorry for the late reply. If I implement codeblock segment, its going to
>>>> affect from packet decoding process to the subsequent deoding process till
>>>> the last. Therefore, I have to be properly planned in order to accomplish
>>>> these changes. Here, I have put patch for incorporating multiple codeblock
>>>> segment. I had to create two more structures and modify J2KCblk sturucture
>>>> as well. This patch is just for the modification/creation on the structures.
>>>> I am also writing some miscellaneous function and I will post those in my
>>>> subsequent emails.
>>>>
>>>
>> I have modified the decode_packet function incorporating multiple codeword
>> segment. Here, I have attached the patch for the required changes. I have
>> taken the help from jasper code while writing this code, because only the
>> document is not sufficient to incorporate these changes. I have not tested
>> this code yet. Once, I test it, I also let you know. If you have any
>> suggestion on this patch, please let me know.
>>
>>
>>
>
> While doing arithmetic coding operation in decode_cblk function one
> term/variable is "bpno". Coding operation (decode_sigpass, decode_refpass,
> decode_clpass) uses this variable to determine the data of each codeblock in
> different contexts. This variable has been set in our decoder:
>
>
> bpno = cblk->nonzerobits - 1
>
> And, jasper has set this variable as follows:
>
> bpno = band->roishift + band->numbps - 1 - (cblk->numimsbs + (seg->passno +
> i - cblk->firstpassno + 2) / 3);
>
> band->roishift is the value got from processing the RGN marker and
> band->numbps is also the value got from some other marker. Our decoder has
> not processed this marker.  cblk->numimsbs is similar to our decoder's
> cblk->nonzerobits. Other part of this variable is segment specific and that
> makes sense. I need you suggestion on how to set this variable. I will
> explain more tomorrow on IRC chat.
>
>
>
Here, I have attached two patches which cove all changes due to multiple
codeblock segment. I have tested decode_packet function, but not decode_cblk
yet.

Thanks

-- 
Rukhsana Ruby
Phd Student
Department of Electrical & Computer Engineering
The University of British Columbia
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