Channel Changing Delay problem ( Too much lag, may not purchase because of this )

[jcircelli]

I'm using the Trial version of SageTV 2.0.20 ( newest one ) and am seriously considering buying it. There is one issue that is holding up this decision.

When using the LiveTV mode, there is a 2 to 3 second delay when switching channels. Now, my understanding is that SageTV will start writing the data stream immediatley to disk as soon as the channel is switched, but there is a delay before it starts reading the stream and decoding it so the user can watch it. Upon doing some research, I changed the following two SageTV config options to the following( hoping it would reduce the delay between changing channels) :

videoframe/local_encoding_to_playback_delay = 0
videoframe/time_to_start_into_tv_file_playback = 0

This did work to some degree. Now, there is just around a 1 second delay when changing channels, but when comparing the ouput of my SageTV to a regular TV, the SageTV output is still about 1 second behind REAL LIVE TV.

I find this to be a pretty bad architecture decision. They should have designed this app so that the screen displays directly from the from the input source (tuner), and writes a file at the same time. The file never comes into play unless you decided to pause or rewind the current channel. Like most normal DVRs do ( my brighthouse dvr for example ).

Can anyone either A, shed some light on this. Am I wrong. and B, if I'm not wrong, will version 2.1 solve this problem. Live TV in my opinion is not a 1 second delay of a cable broadcast, it's a 0 second delay. I've spoke with people that have media center edition 2005, they say that changing channels is pretty much instant, like you would expect.

Thanks.

Jutsin

[mlbdude]

The hardware used by SageTV (the Hauppauge 250 or something similar) is designed to be used in a PVR system. At the driver level it writes out to a file and Sage reads this. This has nothing to do with SageTV.

There are no PC based PVR packages that do it differently. Unless they use software encoders.

MCE 2005 works exactly the same way. Changing channels is instant but you are alwasy watching behind a bit.

[ToxMox]

I haven't seen any PVR including my TiVos not have a delay between real TV and PVR TV. For me the delay is less than one second on Sage but I wouldn't call it instant but it is slightly less than my TiVo's delay. If you know someone with MCE 2005 I would recommend actually going over and trying it for yourself to get a real feel for it and not just take people's word.

[jcircelli]

Thanks for the feed back on watching REAL TV vs. SageTv's Live TV. I can deal with the fact that there is a delay between the two.

However, changing channels still takes just over a second, even with the tweaks I mentioned, ( which I recommend you try if possible ).

I'm going to try MCE 2005 on this same configuration in the next day or two, to see if if/how much it differs from sage tv. I will post back the results.

--


Has anyone worked with sage tv 2.1 beta to see if it changes channels quicker ? This is my main concern now.

[mlbdude]

I have both SageTV 2.1 and MCE05. Both work identical in this respect. I would assume that the speed of your CPU and condition of your HD could affect this, but on my Athlon 2.5 channel change is under 1 second.

However, now that you are using a PVR, why are you channel surfing?

[ToxMox]

I wonder if any antivirus software could have any affect. I don't have any virus app running on my Sage box.

[jcircelli]

I do have Anitvirus installed, but whether it is enable or disabled, I get the same performance. ( tried both )

Also, I am using Celeron 2.0ghz, and 512 ram PC3200.
120GB seagate, with 8mb Buffer.
ATI Radeon 9100 IGP graphics.
ATI eHome Wonder Tuner ( w/o FM )
I've create the NTFS 64k block partition as suggested in other posts.
I've also tweaked the sageTv config to increase the number of Buffers used for MPEG decoding. ( didn't make a difference ).

CPU never goes above 25-30% when watching liveTV, Less than that when in sleep mode. ram never uses more than 200M or so.

I am using the CyberLink PowerDVD decoder not sure if this has any impact on the delay. ( Is there another that might make a difference )


Justin

[briands]

I always felt this would be a problem for me too. This is why I have avoided satelite TV and Digital cable. I was surprised to learn that now that the PVR is recording content that I want to watch and it is available when I want to watch it and I can skip commercials, I rarely surf channels anymore. I guess the exception is football on Sunday when there are multiple games on at once. Even then, I usually watch one while the other records and I can watch it much faster from the disk after the first is over.

If you've not used a PVR much, I think you will be surprised how your viewing habits will change.

[natesneat2000]

I agree. Why channel surf? I mean, why? To see what's on? Look at the guide - it shows 5 channels and 3 hours at once. Want to watch something? REcord it, and skip the ads. Or, at the least, watch it live after finding it in the guide. The annoying thing is it's still changing when my recordings start-a disadvantage of digital cable and the dish.

[heffe2001]

I can also say from experience, 2k5 works the same as Sage in the respect of channel changes.

[RageFury]

This is a serious problem, that I can't believe exists like this. I mean I don't want a damn delay to see what's on - and I'm trying to make an HTPC for my mom for Christmas.....she doesn't know anything about computers past how to check her email - and since all the tuners are capped at 125 channels, or 181, you can't use that for digital cable since it goes up to the 900's.....

With all of todays technology.....it's amazing such idiotic problems as multi-second delays on hardware encoding TV tuners exist.

[heffe2001]

Hey, it's not as bad as my old Dish network 7200 PVR, it has about a 5 or 6 second delay. I guess the delay between when you receive something on cable and when it plays on digital satelite is too much to eh? Or for that matter, the delay on a Tivo.

It's also been discussed before, it's not the TV tuner people fault that they can't use the digital cable channels, it's how the signal is transmitted. Blame your cable company there.

[salsbst]

This is a serious problem, that I can't believe exists like this. I mean I don't want a damn delay to see what's on - and I'm trying to make an HTPC for my mom for Christmas.....she doesn't know anything about computers past how to check her email - and since all the tuners are capped at 125 channels, or 181, you can't use that for digital cable since it goes up to the 900's.....

With all of todays technology.....it's amazing such idiotic problems as multi-second delays on hardware encoding TV tuners exist.

You might not want to gift a PVR until you've gotten used to them yourself -- as you're learning, it's a different kind of experience.

As to the channel issue, analog cable is only able to go up to 125. Digital cable goes higher, and those of us who use PVRs with digital cable use a set top box and feed the encoder card with an s-video or composite signal, and use an infrared transmitter or a serial cable to control the cable box (automatically) from SageTv.