[mythtv] DSM-CC object carousel parser and storage patch for 0.18.1

Stuart Auchterlonie stuarta at squashedfrog.net
Fri Sep 30 23:00:09 UTC 2005

On Fri, Sep 23, 2005 at 11:39:09AM +0300, John Papaioannou wrote:
> Hi again, and sorry for the delay.
> The tarball can be grabbed here:
> http://www.18-24.gr/stuff/mythtv_dsmcc_patch.tar.gz
> Extract on 0.18.1 and be sure to read the brief intro in my first post to
> get it running. I 'd be happy to provide more information about anything,
> but unfortunately as right now I am back in my home country of Greece and we
> don't have DVB-T here, that's as far as I can go.
> Re the code being good: there are some weird things in there (e.g.
> inconsistent use of either std::map or QMap) that have a strange explanation
> (myth segfaulting seemingly without reason), some stuff is
> not-quite-complete due to time pressure, and some things could be seriously
> improved (more clever memory management). But overall I think you won't be
> disappointed.

John, here are some comments.

You have tied the detection & decoding of the DSMCC stream into
siparser. While this works fine for just decoding the data, it
probably isn't the best long term solution.

(The rest of this is for discussion....)

There are two method we could use to implement live tv.

1. Decode the DSMCC on the backend, and then pass bits and pieces
through to the frontend for interpretation and display. This would
require the frontend to then talk to the backend to request data
out of the Object Carousel Cache. (This is how John's done it)

2. Pass the whole stream through to the frontend and do the decoding
and caching at the frontend. This could be implemented as an avcodec
much like the subtitles are done at the moment.

My favoured approach would be to implement #2. It should be cleaner
and easier to maintain in the long run.

Comments everyone?

We can still use all the parsing and caching stuff John's written,
we will just have to tie it all together in a different way.


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