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hondo3 · (This post was last modified: 2012-09-10, 23:11 by hondo3.)

Can users of the various PVR plugins let me know approximately how long it takes to change channels on their setup?

So ideally I'd like to know what pvr plugin you're using, how long the channel change is taking, and whether the server is on the same machine or another machine.

Thanks!

artrafael · 2012-09-10, 23:45

Welcome to the XBMC forums.

You should also ask what tuner hardware others are using in addition to the PVR software and system topology. The hardware will have some bearing on how quickly channel switching will occur.

hondo3 · 2012-09-11, 02:23

True, the more info they can give the better, but at the very least I want to know what plugin they were using, and how long channel changes were taking.

I've tried searching but couldn't really find any info on this.

hondo3 · 2012-09-11, 02:38

I've actually created a new PVR plugin, and it's basically working, but channel change times are less than stellar, so I'm hoping to find out how the other tv plugins are performing in comparison.

cowfodder · 2012-09-11, 03:21

I'm using tvheadend with the old dual tuner hdhomerun receiving qam channels from my cable. Channel changes are typically around a second or less.

hondo3 · 2012-09-11, 03:34

That sounds great. Mine are much slower than that.

Is tvheadend on the same machine or a elsewhere on the network?

hondo3 · (This post was last modified: 2012-09-11, 03:58 by hondo3.)

Looking at the logs, I can see I'm deliver transport stream data from ReadLiveStream in less than a second, but it appears to take about 5 seconds before XBMC is ready to start playback. It appears to be taking a very long time for it to determine the video format before it starts playback after the channel change.

Quote:13:47:00 T:9644 DEBUG: AddOnLog: PVR Client: OpenLiveStream(oid=7560)
...
13:47:00 T:9644 DEBUG: AddOnLog: PVR Client: ReadLiveStream
13:47:00 T:9644 DEBUG: AddOnLog: PVR Client: ReadLiveStream
13:47:00 T:9644 DEBUG: CDVDDemuxFFmpeg::Open - avformat_find_stream_info starting
...
13:47:00 T:9644 DEBUG: AddOnLog: PVR Client: ReadLiveStream
13:47:00 T:9644 DEBUG: AddOnLog: PVR Client: ReadLiveStream
13:47:00 T:9644 DEBUG: AddOnLog: PVR Client: ReadLiveStream
...
13:47:06 T:9644 DEBUG: CDVDDemuxFFmpeg::Open - av_find_stream_info finished

How is tvheadend making this happen quicker?

Can I somehow tell it the format and pids etc, so that it doesn't need to spend 6 seconds doing it?

hondo3 · (This post was last modified: 2012-09-11, 08:43 by hondo3.)

I'm still interested to hear how quickly other addons (mediaportal/argus/mythtv) are changing channels.

benoire · 2012-09-11, 08:43

Hi Hondo3,

I'm using MP TV Server and I have sub 1s changes if the current tuner is active, a little bit longer if I'm switching to a different tuner. This is on SD channels. 1080i channels take 2-3 seconds in total, but some of that might be due to the decryption API I'm using to watch Sky.

hondo3 · (This post was last modified: 2012-09-11, 08:48 by hondo3.)

I have found with a small 1 line change to DVDDemuxFFmpeg.cpp, I can get the live tv channel change time to a much more reasonable 2.0-2.5 seconds, but I'm sure it might break playback of some other file types elsewhere in xbmc so I'd probably need to do it a different way. I'd hoped to come up with a way which could be isolated to within my addon, and not require changes to the pvr framework itself.

(2012-09-11, 08:43)benoire Wrote: Hi Hondo3,

I'm using MP TV Server and I have sub 1s changes if the current tuner is active, a little bit longer if I'm switching to a different tuner. This is on SD channels. 1080i channels take 2-3 seconds in total, but some of that might be due to the decryption API I'm using to watch Sky.

Thanks for the info. Is that MP server on the same machine?

I dont know much about this addon, but do you know if it's using RTSP or TSReader? Looking at the code, it appears this could have an impact on which demux is used, and could be avoiding the issue I'm seeing.

benoire · 2012-09-11, 09:43

The MP Server is on the main HTPC (single seat) and connected via TSReader. The office PC is connected over 100mb lan and is also using TSReader, that again has very similar channel change times.

A600 · 2012-09-11, 14:21

(2012-09-11, 08:44)hondo3 Wrote: I have found with a small 1 line change to DVDDemuxFFmpeg.cpp

Could you post that change?

TIA.

hondo3 · (This post was last modified: 2012-09-11, 19:10 by hondo3.)

(2012-09-11, 14:21)A600 Wrote:
(2012-09-11, 08:44)hondo3 Wrote: I have found with a small 1 line change to DVDDemuxFFmpeg.cpp

Could you post that change?

Are you using a capture addon that is also slow? Which one is it? If so, any chance you could start xbmc, start live tv, change channels a couple of times, then post your xbmc.log? I'll check if that patch would help you.

A600 · (This post was last modified: 2012-09-11, 22:00 by A600.)

(2012-09-11, 18:56)hondo3 Wrote: Are you using a capture addon that is also slow? Which one is it? If so, any chance you could start xbmc, start live tv, change channels a couple of times, then post your xbmc.log? I'll check if that patch would help you.

I was only curious. That's all Smile

hondo3 · (This post was last modified: 2012-09-11, 22:47 by hondo3.)

I basically changed from "streaminfo = true" to "streaminfo = false" in DVDDemuxFFmpeg.cpp, which controls whether it goes into this section of code that does the slow avformat_find_stream_info call. Without this, the PVR still seems to give me live tv without any problem, and now abou 5 seconds quicker to change channels. As I said though, it may break playback in other areas, so not something I'd consider a long term fix.