Sloooow Channel changing

[jphhughes]

I have been using the USB-UIRT with SageTV for come time now, it is a great product. However the channel changing speed is oh so Slooooow. I have a Scientific Atlantic 4200 STB. It takes about four second to change a channel. I have read through this forum but did not find and answer. Does the header setting in the .ir file allow adjusting of the channel change speed, if so what numbers do I need to adjust. These are the first few lines of the .ir files I am using. Thanks for any help

SciAtl4200USBUIRT 56000 411 3 600 1000
RepeatCount 4
1 0000 0049 0000 0018 00bf 00b8 0030 008f 0030 008f 0030 0030 0030 008f 0030 008f 0030 0030 0030 0030 0030 0030 0030 0030 0030 008f 0030 0030 0030 0030 0030 0030 0030 008f 0030 0030 0030 0030 0030 008f 0030 008f 0030 008f 0030 008f 0030 0030 0030 0090 0030 076a

[jrhees]

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

[jphhughes]

Jon

Thanks for the detailed reply. After performing additional testing on the basis of your feedback I have concluded that the problems is the "enter" command. At this stage it appears that the cleanest solution is to have SageTV create a new ir file making sure the "enter" function is included.

I ir file that I am using is actually one you created for me quite some time ago. I have since modified it for use with the zone control feature of the USB-UIRT as I am controlling two STB with SageTV.

Thanks again for your help.

[rhubarb]

A good trick for working out the right repeat count and delay between transmissions is to get the Logger and USBUIRT plugins for girder, and put the USBUIRT receiver next to your STB while you (successfully) change channels yourself with the normal remote control.

The logger will show a separate event for each "repeat" of the same signal as you hold a button. This gives you the repeat count.

Also the logger shows the exact time down to the millisecond that each event was received, which tells you the delay.

So now you can set up your repeat count and delay to match those that you normally produce with your remote.