Time to change channel

[Paul_B]

I'm looking for others experience on how long it takes to change channel or for video to appear when slecting a channel in TV guide. For me it seems to be about 15 seconds but I'm not sure why it takes so long

Paul

[sub]

Time to startup on first channel will vary quite a bit from device to device. I just tried the HVR-4400 card I happened to have in my machine. First start from tv guide was 8 seconds, second and subsequent starts from the tv guide took about 6 seconds.

Changing channels in a running live tv session takes less than a second for channels on the same frequency, about a second and half for channels on a different frequency. Whatever your device, changing to a channel on the same frequency should be similar to mine (around a second). Changing to a different frequency may take longer if your device is slow at tuning/.

[sub]

That previous test was on DVB-S with MPEG2 channels. I decided to plugin a DVB-T stick and try that too. Our DVB-T channels use H.264.

This starts live tv in about 3 seconds from the tv guide, with no real difference between first and subsequent attempts.

Channel changes on this device seem to take about a second and a half on the same frequency, and two seconds to channels on other frequencies.

[imilne]

With my Hauppauge Nova-T USB2 (DVB-T, mpeg2 channels), it took about 6 seconds to start initially, then about 3 on subsequent goes. Channel changes on the same frequency were easily less than a second, and very slightly slower than that between frequencies.

[mvallevand]

I was testing the NMT this weekend, which should be slower than the PC tuning, I found to going from HD-PVR to ATSC takes just over four seconds and from ATSC to HD-PVR just over 7. Changing between analog channels is also good 3-4 seconds. What I did find is the very first analog tune was always very slow but after that it is fast.

I tried another test just now and it took over 14 seconds to start.

Code:

2011-03-01 16:18:54.372    [DEBUG][6]    Tuning to channel: 2
2011-03-01 16:18:54.673    [DEBUG][6]    Tuner reports frequency: 55250000
2011-03-01 16:18:54.673    [DEBUG][6]    About to switch AnalogRecorder to target:
LIVE&C:\Temp\live-CICA-5957.ts
2011-03-01 16:18:54.687    [DEBUG][6]    Live TV handle: 0x5F50002
2011-03-01 16:19:04.830    [DEBUG][6]    Renew lease ok (0x5F50002)
2011-03-01 16:19:08.621    [DEBUG][6]    StartStream(6866:CIIIOT)

Martin

[Reddwarf]

Here it takes about 2-3 seconds to start live-tv and less than half a second to change channel. What takes 10-15 seconds is to start up a channel on the dvb-t that has a HW-CAM attached, but channel changing is pretty swift on that card too.

[smajor]

With my HD-PVR it takes about 7 seconds to start live TV and 4, maybe 5 seconds to change channels with it.

[Paul_B]

Thanks for all the replies I'll have to do some further investigation with my Hauppauge card. Technically what is the reason Sky boxes take less than a second (i.e. no perceivable delay) whereas computer cards take several seconds at best?

[sub]

Technically what is the reason Sky boxes take less than a second (i.e. no perceivable delay) whereas computer cards take several seconds at best?

As myself, Reddwarf and imilne said above, it is taking about a second to change channel (some slightly less, some slightly more). Its approximately the same time as most set top boxes I've seen. If anything, I'd say NPVR takes maybe half a second longer than set top boxes, because of extra overheads of drivers, USB, various Window's layers etc. Not a lot of difference though.

The other couple of guys, mvallevand and smajor, are using HDPVR, which adds a couple of seconds in it's encoding process. They're also using blasters to control external set top boxes, which adds some time too. mvallevand is also giving times to change channels on an NMT device, so that adds more time, since the channel is being streaming across the network to a remote device. If you're just watching digital with a DVB/ATSC/QAM device, your times should be a lot quicker than these HDPVR setups.

[siliconaudio]

I'm running DVB-S only. Channel changes on the same transponder take probably under a second. Channel changes that need to switch to another satellite transponder take a little longer, but still less than 2 seconds. I suspect the DVB card and its drivers play a big part in this. I remember back about a year ago, I updated my DVB-S drivers, and channel changes sped up considerably.