How does the TV server/setup work? (1 Viewer)

[gfmoore]

Hi again - hope I don't hear too many sighs!

Could someone care to explain, or direct me to the relevant place, as to how the TV setup works. (I am re-requesting this as no-one might have noticed in my post on the S500) as I would still like to debug my issue.

In particular what happens when parameters are sent to the tv card (esp sat) driver. What does it do, how does it recognise signals and interpret them. I assume this is something to do with "graphs". What creates these, and how can they be tested (I have graphedit, but no idea how I could work with it.

In particular I would like to see what signal the driver outputs before it is sent to the lnb or graph, or is that a stupid question?

Is any of this sensible?, i.e. please don't flame me for being ignorant

Gordon

 

[mm1352000]

Hi again Gordon

Could someone care to explain, or direct me to the relevant place, as to how the TV setup works. (I am re-requesting this as no-one might have noticed in my post on the S500) as I would still like to debug my issue.

I am not sure if you mean the code or the interface. If the interface then the best resource is the wiki. If you mean the code then you'll have to do your own reading - there is no manual...

In particular what happens when parameters are sent to the tv card (esp sat) driver. What does it do, how does it recognise signals and interpret them.

How a driver responds will vary from driver to driver. BDA doesn't really provide any way to get the actual tuner/demodulator parameters. The only way to really debug it would be if the driver had a custom interface for querying it about what state the demodulator and tuner were in. The only drivers that I know of with that functionality is TBS drivers, but I've never tested it and it may not work in the middle of a tune request process (because the parameters may be applied at the end of the request). Doing it with your Compro tuner is probably a lost cause even if they supply us with their API (which I have still not heard back about).

I assume this is something to do with "graphs". What creates these, and how can they be tested (I have graphedit, but no idea how I could work with it.

A topic for *many* books. The short answer is that TV Server creates a graph that writes the tuner output to timeshift/recording files, and MP client creates a graph that reads that file and makes it play. More generally, some device drivers such as tuners and sound cards expose filters to the operating system. Filters are the building blocks of graphs. TV tuners expose source filters. These are connected to some kind of splitter filter (eg. Haali, LAV) which can separate video from audio from data. The splitters provide connections for codecs, which are are filters that understand the formats of the sub streams and can decode them into "raw" video, audio, or more generally "some format" that renderers can understand. Renderers (which are also filters) are "sinks" or consumers for streams - they represent devices such as the display, sound output, or files.

If you want to understand TV Server graph structures then you can open the .grf files in your TV Server config folder (C:\Documents and Settings\All Users\Application Data\Team MediaPortal\MediaPortal TV Server on XP, C:\ProgramData\Team MediaPortal\MediaPortal TV Server on Vista/7). If you want to understand the client side graph then play a video in MP, open Graphedit/Graphstudio, click "file", "connect to remote graph", select the listed graph, then click okay. Note: not all programs expose the graph. You're using Windows 7; connecting to the remote graph might not work for you.

In particular I would like to see what signal the driver outputs before it is sent to the lnb or graph, or is that a stupid question?

That doesn't make sense. As I already said, if you want to monitor what the driver is doing then you need a debug interface for it, and we don't have access to such an interface for your Compro (if one even exists). In terms of the signals that are sent to the LNB: you'd need a multimeter (or better, an oscilloscope) to monitor the signals in the cable if you wanted to check that.

Is any of this sensible?, i.e. please don't flame me for being ignorant

I won't flame you, but I can't give you any better than this post. Some of the questions are sensible, but honestly learning this stuff took me months. I read a lot and looked at a *lot* of code, and I'd been using MP for a couple of years before I started investigating. Nobody is going to be able to give the info to you on a plate. I'm genuinely sorry that your tuner isn't working with MP and I'd like it to work too. I know you're desperate to get it going but you're going to have to either be patient or hassle Compro. Only they can really give us the information that we need unless you're *incredibly* lucky. The problem is that the order in which instructions are sent to the driver is critical - if you do it wrong then you get what we've currently got with your S500. No output with no way to debug...

mm

 

[gfmoore]

Hi mm,

once again thanks for all your time and effort to provide this information. I hope you realise I am just trying to be pro-active and I am wanting to learn how this works so I can help in solving my own problem as I realise the S500 is deprecated and no-one else seems to be using it (with anything).

I actually do have a toy lcd oscilloscope and I am currently investigating what, if any, diseqc signals it is sending to my motor (it is sending something), and why the motor won't respond.

Yes I am impatient I guess, as it is a working card that picks up HD (and supposedly drives motors). I am not aware of any other card that can do that. and I am starting to hate ms media center with a passion. I once tried to get into mcml - probably the worst programming experience of my life, though I did manage to get an app working eventually.

I very much doubt we will get anything from Compro, so it looks like we are stuck for now, which I find incredibly frustrating, since we know it works!!! boo hoo cry cry.

If its bda compliant, and I guess that's a big assumption, I guess I need to develop some kind of test program that can interrogate the driver, using the bda protocols. Guess I've got some heavy duty research to do.

Still I was able to watch the sublime beauty of FC Barcelona in HD without stuttering last night.

Gordon Moore (the real one, not the American imposter!) lol