by jrhees » Thu Jan 06, 2005 9:44 pm
There are several things which affect channel changing speed. The quickest channel changing speed is going to vary greatly depending on the type of IR codes your STB uses as well as your STB's IR receiver:
If SageTV needs to set your channel to '123' then it must:
Transmit '1' for x length of time
After transmission is complete, Wait y length of time
Transmit '2' for x length of time
After transmission is complete, Wait y length of time
Transmit '3' for x length of time
After transmission is complete, Wait y length of time
In addition, it might also have to send an 'enter', or equivalent.
You may want to look into how many digits are being sent to see if this can be reduced. Beyond that, the other two parameters to speed things up are reducing x and y. The x parameter (which is set by 'RepeatCount x')is how long each IR digit is transmitted. This is similar to how long you hold your finger on a remote button. Some STB's need longer IR blasts than others. Try reducing this number in single steps (try 3, 2 and 1). If the x value becomes too small for your STB then your STB will stop seeing the digits altogether.
The y parameter (spacing between digits) must be long enough that your STB 'thinks' you've removed your finger from one button on your remote and placed it on another. The best place to adjust this is within Sage itself. It *is* one of the numbers in the file header, but I'm not sure which one.
The easiest way for you to tell you're having an effect is to look at the red LED on the USB-UIRT when it transmits the digits. By the duration and spacing between the blinks, you'll know how you've affected x and y.
Another thing you might notice is that part of the slowness is also that Sage waits after you've requested a channel change before it even begins sending the channel change. I believe they do this to aid in 'surfing', in case you're trying to pass a channel by.
-Jon