Network encoder channel change delay

[K O]

I'm sure this is beating a dead horse, but I can't help but think this has got to be fixable.

When watching live TV on a network encoder (R5000 in my case), when one show ends and another starts, there's a pause because of the delay in stopping, re-tuning the channel, and re-starting. This takes about 8 seconds, not the end of the world, but then again not the same as watching TV without SageTV.

What I'm wondering is why can't SageTV detect when the end of a show is coming, look for an unused network tuner, start tuning that channel and recording that stream so that when the first show ends, the stream can switch and the gap is near instant? This would go a long way to improve the WAF. If it's not possible, I'm curious to understand what the technical limitation is that's preventing this.

[Fuzzy]

Sage did fix this for a lot of other tuners - however, It's not done by changing to another tuner, it's done by simply keeping the existing tuner plugging away, and just splitting out to a new file. This is harder to do with network encoders, as all sage does is tell the encoder what channel to tune, and what file to write it too. The way to fix it would be to have sage issue a new command to the network encoder to have IT transfer recordings to the new file without interrupting the stream. It would then be up to the encoder to accept this command and transition to the new file at the next transitionable point in the stream. The problem here being I'm not sure NextCom is going to be doing much more work on the R-5000 at all at this point, with the numbers of supported boxes dropping significantly, so do the numbers of new customers, and therefore, income. If they aren't going to handle it, it might be something that a proxy app might be able to handle - could be tricky though.

[Comitizer]

There is a parameter that enables quick changes for networks encoders. The question is whether or not it would work with your encoder. Check the Sage 7 release notes for the specific parameter. I'm not sure what it is off the top of my head.

If you do decide to enable it, make sure that you test it extensively before you trust it...

[Fuzzy]

According to sage, it requires support from the encoder - which means it's really just there for SageTV Network Encoders at this point.

[mkanet]

KO, it takes approximately ~.5 seconds to ~2 seconds when changing to a new channel on a well-optimized setup. When I'm channel surfing, it takes about .5 - 1 seconds to tune. How am I able to do that instead of waiting 8 seconds? It has to do with how you have your setup configured; and the performance of the system resources. Here are some tips that made noticeable changes.

1. Make sure you have plenty of physical RAM available at all times. I think it's good to have 4GB's of RAM on the PC; especially since RAM is so cheap. You may not use it all; but its good to have it there just in case. Also, uninstall all apps that get loaded in memory on Windows startup; unless they are absolutely needed for sageTV (look at all the icons in the Windows system tray to see what you dont need. It's strongly advised not to use the PC as a workstation unless you REALLY have to; as, it can introduce complications. Try disabling all windows services that do are obvious you dont use. Be careful; as, you might compromise Windows stability if you disable the wrong service.

2. Once you have disabled all possible memory resident apps and service.. make sure you have also disabled superfetch and possibly prefetch services; at least disable superfetch.. especially if you have Vista. You wont need them anyway if your server is dedicated to sageTV/R5000; especially if you have an SSD (as described in #4 below)

3. Try both R5000 software/driver versions 2.0c and 3.1d (you can download them directly from here. Some people say 2.0c is faster; some people say 3.1d is faster. I have a feeling whatever you're using, you should try switching to the other version. For my system, 2.0c works the best.. along with a 3rd party "proxy" app to enhance stability/functionality.

4. The biggest overall performance gain I ever got in general for my server was when I swapped out my standard mechanical hard disk drive with a high end SSD (putting my boot partition/OS/drivers/installed apps/all temp files/pagefile on it). Keep in mind that there are some Windows system/service/driver functions that REQUIRE reading/writing to Windows pagefiles, temp files, database files (even if you have all the RAM in the world). After switching to an SSD, when I load apps that control hardware peripherals (such as TV tuners, local network encoders, etc), initializing/sending commands to the device is instantly (limited only by the hardware peripheral performance itself, not software/drivers). For example, the R5000 drivers and all related system functions would act as everything is running in RAM; except with the advantage of using non-volatile memory. Obviously, you dont want to put your TV recordings on the SSD; as they are generally relatively small (mine is only 256GBs with a wopping 256MB onboard cache). Also, make sure your pagefile is manually set to to NOT grow or shrink.... minimum and maximum site set to the optimal size (in respect to how much available system RAM you have installed).

With all these suggestions above, you an reduce the response time for your R5000 network encoders to just the time it takes for the hardware to respond to commands and stream; which should by no more than 1.5 usually when changing channels; many times less than 1 second; especially when channel surfing. Seldom, you might see it take as much as 2 seconds.

PS: Make sure you have the SageTV setting under Detailed setup, "Always tune channel" to false. and the following settings in your Sage.properties file:
fast_network_encoder_switch=false (for all your R5000 encoders)
seeker/fast_mux_switch=false
videoframe/safe_fast_file_switching=false

Dont be bashful to ask questions; even if you think it might be a dumb question. Good luck.

-Michael

Originally Posted by K O

I'm sure this is beating a dead horse, but I can't help but think this has got to be fixable.

When watching live TV on a network encoder (R5000 in my case), when one show ends and another starts, there's a pause because of the delay in stopping, re-tuning the channel, and re-starting. This takes about 8 seconds, not the end of the world, but then again not the same as watching TV without SageTV.

What I'm wondering is why can't SageTV detect when the end of a show is coming, look for an unused network tuner, start tuning that channel and recording that stream so that when the first show ends, the stream can switch and the gap is near instant? This would go a long way to improve the WAF. If it's not possible, I'm curious to understand what the technical limitation is that's preventing this.