[FFmpeg-devel] [RFC PATCH v2] libavcodec/jpeg2000_parser: Add jpeg2000 parser

Gautam Ramakrishnan gautamramk at gmail.com
Wed May 20 18:18:41 EEST 2020


On Tue, Apr 21, 2020 at 3:41 AM Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> On Mon, Apr 20, 2020 at 04:13:44PM +0530, Gautam Ramakrishnan wrote:
> > On Mon, Apr 20, 2020 at 3:38 PM Michael Niedermayer
> > <michael at niedermayer.cc> wrote:
> > >
> > > On Mon, Apr 20, 2020 at 01:36:47AM +0530, gautamramk at gmail.com wrote:
> > > > From: Gautam Ramakrishnan <gautamramk at gmail.com>
> > > >
> > > > I have attempted to write a JPEG2000 Parser. Need
> > > > help on testing the code and some tips on how to
> > >
> > > to test the code i would sugest to generate a file
> > > or files with many jpeg2000 images and then try to
> > > decode it to -f framecrc
> > This helps me check whether the image is correct by comparing the CRC value?
> > > if that work repeat while varying the packet size
> > > input to the parser, a parser must work with anything
> > > from 1 byte per input to sizes being larger than a
> > > single frame.
> > >
> > So a packet to a parser is basically a smaller unit to which the parser is fed
> > data to? When I tried printing buffer size during parse, it shows 4096.
>
> > Does that mean the packet size was 4096?
>
> yes, that likely comes from
> libavformat/img2dec.c:            size[0] = 4096;
>From my understanding of the documentation, the -packetsize option can
change the
value from 4096 to any particular I want right? However when I try setting the
-packetsize option, the buf_size variable still shows up as 4096.
>
> random pieces of bytes -> parser -> sequence of packets representing frames
>
> thanks
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
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-- 
-------------
Gautam |


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