[mythtv] Re: [mythtv-commits] mythtv commit: r7245 by danielk

Stuart Auchterlonie stuarta at squashedfrog.net
Wed Sep 14 00:44:19 UTC 2005

On Tue, Sep 13, 2005 at 12:08:49PM +0000, mythtv at cvs.mythtv.org wrote:
>       Author: danielk
>         Date: 2005-09-13 12:08:48 +0000 (Tue, 13 Sep 2005)
> New Revision: 7245
>    Changeset: http://cvs.mythtv.org/trac/changeset/7245
> Modified:
>    trunk/mythtv/libs/libmythtv/mpeg/mpegtables.cpp
>    trunk/mythtv/libs/libmythtv/mpeg/mpegtables.h
> Log:
> Stuart Auchterlonie's patch to allow MythTV to recognize DSMCC data streams.

One comment though Daniel. There isn't a lot to be gained by separately
identifying the different types allocated to DSMCC with respect to 
printing out this information in the logfiles. There are not a lot
of hard and fast rules as to what data is in what type of stream. In
practice it seems that all the different types of dsmcc data are 
primarily sent out under a single stream type.

Here in the UK, on almost every channel where dsmcc data is broadcast
it is done so under stream id of 0x0b. One of the muxes, used by the
BBC mainly, contains, per channel, about 6x 0x0b data streams and 1x
0x0d data stream.

I've not seen 0x0a or 0x0c in the wild, only in documents.

So it is sufficient to say streams 0x0a - 0x0d are of type
"object carousel"

(I'm referring here to your changes in mpegtables.cpp as opposed
to my original patched version.)

Also a number of the other currently unknown 2nd level descriptors
are as follows.

0x0e - Appears to be maximum bitrate descriptor (according to dvbsnoop)
0x13 - DSMCC Data Carousel ID Descriptor.
0x14 - DSMCC Data Association Tag Descriptor.


ps. Wonder if 0x0e is actually what dvbsnoop thinks it is, and if we
can use this information elsewhere to avoid excess pauses?

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