Re: JPEG 2000 codec support

Hey,

> In the context of an EU-funded project called PREFORMA dealing with
> long-term preservation archives, we need to wrap JPEG 2000 frames
> using MKV.

> I looked in mail archives and documentation, but it seems there is
> currently no such JPEG 2000 support within Matroska.

That's true.

> My questions:
> * Is there any plan to include JPEG 2000 as one of the supported codec
>   in Matroska ? If yes, what would be the timeframe ?

We don't have any concrete plans for such support.

> * Is there any work already done in that direction ?

None that I know of.


> * What would be the steps to follow to get this codec supported by
>   Matroska ?

There are roughly three areas that would need work:

1. Define a codec mapping similar to the ones on [1]. I guess that JPEG
   2000 would be a codec that wouldn't need any initialization data,
   therefore there would be no CodecPrivate element. All we'd need would
   be a CodecID; V_JPEG2000 would be the obvious choice here.

2. Adopt one of the existing Matroska muxers to produce such files. For
   mkvmerge this would be quite some work to be done properly as I guess
   that JPEG 2000 would mean having to read one file per video frame –
   and mkvmerge currently doesn't support reading multiple file for
   inclusion in a single track at all. This would have to play well with
   its GUI (mmg) as well. Support for extraction via mkvextract would
   have to be added as well.

   Another choice might be ffmpeg as I seem to remember that it can read
   multiple files and encode them as a video track already. I don't know
   how much work it would be to modify it as I have little knowledge
   about its internals, though.

3. Add support in players. This could be as simple as adding two lines
   of source code mapping Matroska's new CodecID to the decoder
   definition for the JPEG 2000 codec (often a FourCC or one of
   libavformat's #defines/enums), but it might need more work.

Kind regards,
mosu

[1]  http://www.matroska.org/technical/specs/codecid/index.html

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