[mythtv] DVB integration - first attempt!
Edward.Wildgoose at FRMHedge.com
Wed Apr 23 11:43:52 EDT 2003
Ben, this sounds great. I would like to get a look at it so far, and I will see what I can do about a shell account.
I'm not sure that I quite understand what you are doing though. Here is how I see that we might do this:
- Use an external daemon program to provide the tuning. This is effectively going to be a thin wrapper around dvbstream (and I think it makes sense to wrap the code because it is still presumably evolving?), which needs two interfaces: a) input to take a channel to tune (and this could be as simple as a text string which is looked up in channels.conf) b) output to a (unix socket?) so that it can be picked up by myth
- Modify Myth to: a) read from the external device, and b) modify the channel change code to switch channel in an appropriate way - these would appear be the only two changes required.
I think by seperating things like this then it will make it easier to test and debug.
The point is that I can test your tuning script for you (or write one myself), and I can also send you the MPEG output which you can then use on a machine with no tuner to simulate input into myth.
I'm thinking that a small perl script wrapped around dvbstream would take care of creating a suitable device for myth to access. We can then start working on the myth side and I am happy to knock you up an mpeg stream which just plays in a loop and gets stuffed down the socket in order to simulate the effect of having a card.
Let me know what you think and also an address where you are happy to get a large mpeg test stream (remember this stuff is 15Mbits/sec...)
I think the idea of having an external deamon provide the tuning socket will be useful at this stage anyway, and I like your idea of using dvbstream - this wrapper would easily allow the possibility to run the DVBStream command on a different machine and provide the device locally (perhaps useful on tiny machines with only a single PCI slot?)
Anyway, the main question is how to modify myth??? Do you think it is a simple matter to just alter the MpegRecord.cpp module to ditch the v4l2 stuff, or is something more complicated needed?
From: Ben Bucksch [mailto:linux.news at bucksch.org]
Sent: 23 April 2003 00:07
To: Development of mythtv
Subject: Re: [mythtv] DVB integration - first attempt!
I have been hacking away on DVB stuff for the last 3 days. I have 2
1. Integrating the demuxing and tuning into MythTV (mostly using
existing code from dvbstream). Much of that is done, but it needs to be
hooked up (I know how, but not done yet). It will probably not work at
first, given that I have been writing on the code for 3 days without a
single test (how could I, without card?) apart from compilation.
2. I realized that dvbstream has a telnet interface, so worst comes to
worst, we can still control and ongoing stream and tune it, incl. PIDs.
So, I am attemping to write a generic interface which calls a
configurable command and recieves an MPEG2 stream from it via the pipe
(stdout). The tuning is done via more or less the existing external
command code. It doesn't work out of the box, though, because the
current |Channel| code has accesses to /dev/video all over the place,
and we don't have that with DVB, so it's failing, and I had to avoid that.
I didn't post patches yet, because it's very much work in progress. It
does not work yet, so it would only make remotely sense to a programmer.
If anybody wants to have it nevertheless (it costs a bit time to create
the patch, lots of new files), please say so. Before anybody else starts
to work on the source, I'd be happy to send the patch. I'd be a shame to
Unfortunately, I (as always :-( ) spent much longer on this than I
expected or can affort and have to work now, so I might not be able to
work on it in the next week or so. We'll see.
If anybody could give me a shell account on a computer with DVB card,
that might be useful for testing.
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