What are 'graphs' as related to PVR software?

[thisisnotadrill]

Hello all, this is my first post/thread. I am a n00b as far as PVR software/hardware goes (tomorrow evening will be my first foray) but I am pretty familiar with computers/technology so hopefully you can talk at a fairly high level in explaining this terminology.

In reading as much as I can about GB-PVR I have come across people speaking of graphs frequently, however in my searches (google, gb-pvr wiki, forums) I have yet to come across a good definition for exactly what a graph refers to.

so what is a graph in this context? is it just a video stream?

[sub]

"Graphs" refers to the various playback components used and the way they are hooked up. For example, you might have a "file source" filter hooked up do a splitter filter, feeding a separate audio and video stream to their respective decoders, before being feed to a video render and audio renderer.

[whurlston]

You can see a visual representation of a "graph" in the first post of this thread: http://forums.nextpvr.com/showthread.php?t=25375

[flyswatta]

It's somewhat unusual to use a graph - I've done one once just to see what all the fuss was about. If you get commonly used capture cards then you'll probably never need to mess with them.

[thisisnotadrill]

thank you.

just to make sure i have this: for every 'file source' type (can i assume that these can be both live streams from a tunercard/firewire or a media file from the hdd?) you set up graphs to process them in whatever manner you like?

Are all (most?) custom graphs created in graph edit using a graphical representation?

flyswatta: The reason i am interested is that in searching for how to capture video from a STB over firewire it would appear that graphs are involved in some way (unless someone has already done it for your STB, i guess?)

[carpeVideo]

Look in the sample graphs included with this plug-in - it includes a firewire capture.

Somewhere on this forum I also posted a how to for firewire

http://gbpvr.com/pmwiki/pmwiki.php/Plugin/GraphRecorder

[thisisnotadrill]

Thank you, I will search the forum for your thread/post.

side question, just since this thread has turned towards firewire: I realize you can only record "clear QAM" HD channels (generally just locals) but does that mean its also impossible to watch (but not record) the other HD channels (through the firewire, processed, and output through the video card)?

It would be preferable if i never had to use the STB directly, controlling it only through GB-PVR, though that is looking less and less likely.

[whurlston]

QAM is a different animal from the firewire output. What you can watch or record via the firewire will depend on whether or no your cable company is setting the 5C flag for a particular channel or program.

I get all my locals in clear QAM and record anything a anytime on those stations. With firewire, I found that most of the primetime programming on those stations are flagged and I am unable to watch or record anything.

If you can watch a program on your PC via firewire, you can record it.

[carpeVideo]

I've been lucky on the other side of the coin - I get all locals and most basic clear in both qam and firewire (although the lists are slightly different). So I use both qam, firewire and then s-video capture off of the STB for encrypted channels.

[thisisnotadrill]

thank you the explanation between encrypted QAM and the 5C flag.

I figure between analog cable input, clear QAM channels, and firewire/s-video the only channels I am going to miss out being able to record/view are the non-local HD channels. kind of sucks, but I should be able to always record the SD version and then use bittorrent to get the HD version. I suspect that my girlfriend won't care about not seeing the HD feed if i am not around to switch over the STB output for her and WAF is the big reason I wished there were a way to just pass through the non-recordable HD signals from the STB to computer to television.