2013-02-08, 20:45
Fibo, Spyder, Royfa. This is basically what I am doing:
The first time you set up wmc, it started two services that always run in the background (ehRecvr and ehSched). These services run whether wmc is running or not. They handle the maintaining of the epg database (automatic downloads) and the scheduling of programs to record, and the actual recording of those programs. When wmc is running, it makes requests of these services, for instance to display guide data or start a recording.
My software makes the same requests but is controlled by xbmc. So really I am just using the same services to manage the pvr that wmc is using, no duplication here.
Live TV is different. Doing video programming was new to me a couple of months ago, so I took a look at a number of ways to do it. In particular I spent a long time trying to figure out if I could find some high level interface exposed in the wmc libraries to control live tv, I gave up on this. But through this I learned that wmc makes use of a special set of directshow filters in windows called the “stream buffer engine” (SBE), which MS makes available and it is actually documented (woo hoo!). So my software also makes use of the SBE to do live-tv (actually at a slightly higher level to get hardware independence).
The difference is that wmc uses the output of the sbe directly to drive vid onto the screen (specifically it is uses the sbe filter graph to directly drive the video renderer it uses). I can’t do that for xbmc, so rather I stream the output of the SBE to a file, and use this file to stream to xbmc. As near as I can tell, this is basically the approach of some of the other pvr solutions for xbmc (but I could be be wrong on this). This approach is part of the reason why channel changing is slow, but it also enables other computer’s running xbmc on the lan to watch live tv from the server. Changing channels with sbe itself is fast and easy.
It would be great if xbmc could display and control the sbe graph directly, but I didn't try to find out if this is possible. So you other coders/video experts out there who want to help might want to look into this (or tell me it’s (im)possible). This would solve the channel switching speed, making it the same speed as wmc theoretically - but only for the server computer (the one with the tuners).
My software partitioning is basically the same as the other pvr solutions for xbmc that I have looked at, it is divided into two parts. A server program that runs on the host machine that handles the interface to the wmc services and starts/stops the live streams. This program should always be running, just waiting for xbmc to connect. And an addon in xbmc that interfaces to this server. The addon feeds the data it receives to the GUI in xbmc. I also takes the XBMC commands (recording, livetv, etc) and sends them to the server.
Questions, corrections and criticisms welcome.
The first time you set up wmc, it started two services that always run in the background (ehRecvr and ehSched). These services run whether wmc is running or not. They handle the maintaining of the epg database (automatic downloads) and the scheduling of programs to record, and the actual recording of those programs. When wmc is running, it makes requests of these services, for instance to display guide data or start a recording.
My software makes the same requests but is controlled by xbmc. So really I am just using the same services to manage the pvr that wmc is using, no duplication here.
Live TV is different. Doing video programming was new to me a couple of months ago, so I took a look at a number of ways to do it. In particular I spent a long time trying to figure out if I could find some high level interface exposed in the wmc libraries to control live tv, I gave up on this. But through this I learned that wmc makes use of a special set of directshow filters in windows called the “stream buffer engine” (SBE), which MS makes available and it is actually documented (woo hoo!). So my software also makes use of the SBE to do live-tv (actually at a slightly higher level to get hardware independence).
The difference is that wmc uses the output of the sbe directly to drive vid onto the screen (specifically it is uses the sbe filter graph to directly drive the video renderer it uses). I can’t do that for xbmc, so rather I stream the output of the SBE to a file, and use this file to stream to xbmc. As near as I can tell, this is basically the approach of some of the other pvr solutions for xbmc (but I could be be wrong on this). This approach is part of the reason why channel changing is slow, but it also enables other computer’s running xbmc on the lan to watch live tv from the server. Changing channels with sbe itself is fast and easy.
It would be great if xbmc could display and control the sbe graph directly, but I didn't try to find out if this is possible. So you other coders/video experts out there who want to help might want to look into this (or tell me it’s (im)possible). This would solve the channel switching speed, making it the same speed as wmc theoretically - but only for the server computer (the one with the tuners).
My software partitioning is basically the same as the other pvr solutions for xbmc that I have looked at, it is divided into two parts. A server program that runs on the host machine that handles the interface to the wmc services and starts/stops the live streams. This program should always be running, just waiting for xbmc to connect. And an addon in xbmc that interfaces to this server. The addon feeds the data it receives to the GUI in xbmc. I also takes the XBMC commands (recording, livetv, etc) and sends them to the server.
Questions, corrections and criticisms welcome.
