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Very slow channel switching - Printable Version

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Very slow channel switching - jelleeelco - 2012-02-23 13:23

Hi all,

I hope someone knows the answer to this. Just installed a cablrstar hd2 and configured mediaportal as backend.
It all works, but channel switching takes 10 to 12 secondz. In mediaportal max 2 to 4 (all for sd channels).

Is this hardware related? I have an amd 5200 dualcore, 4gb ram, ssd, and gt520 video card. Or is it normal?

Many thanks in advance,
Jelle

- FernetMenta - 2012-02-23 22:23

This is not an hw issue. I would even consider 2-4 secs as long.

- jelleeelco - 2012-02-24 08:07

Thanks, thats a relief. Any idea were I should find the reason? In the tv server or in settings of xbmc? When switching, it just says "Busy". It looks like it buffers the stream first (checked it yesterday, its now around 8 sec).

- FernetMenta - 2012-02-25 11:06

It might be related to mediaportal add-on or server. Contact margro, he might be able to help. (https://github.com/margro/xbmc)

- margro - 2012-02-26 14:55

Because you did not provide much information about which XBMC pvr build you are using, which version of the addon and whether you are using the backend and frontend on the same machine or on different pc's I can only give a general explanation.

Basically, the contributors that influence the channel switch times are:
  1. the time it takes to tune a particular channel (TV Server)
  2. the time it takes to decrypt an encrypted channel (TV Server/CAM)
  3. the time it takes to start timeshifting (TVServer)
  4. the time it takes to fetch the stream URL / timeshift filename (MediaPortal pvr addon)
  5. the time it takes to start the stream playback (addon + XBMC)


I can't influence 1-3. You can see the time it takes for 1-3 in when using the debug version of the TVServerXBMC plugin (the .exe version).
Note that first time tuning takes longer than a channel switch due to the initialization of your card and the creation of the timeshift buffer (@TV Server).

Currently, there are 2 different MediaPortal pvr addons: "ffmpeg" and "tsreader". The first one is distributed in the builds from Dushmaniac (opdenkamp). The tsreader version is currently only in my builds.

The "ffmpeg" version uses RTSP streams for channel playback and this results in large channel switch times 6-20 sec. One of the reasons is that XBMC's internal ffmpeg library takes quite some time to start the playback of an RTSP url from the TV Server.
Because I can't really speed-up this part, I started with a different approach to re-use parts of the playback code from MediaPortal: the tsreader version.

This addon has much faster channel switch times: 2-5 s in my case. I'm still working on getting this faster, but similar channel switch times as in MediaPortal itself should be possible in your case.

- jelleeelco - 2012-02-27 13:47

Hi Margro,

Thank you for your elaborative answer and apologies for my weak initial post: I should know better... I USED the latest version from Opdenkamp and indeed the FFmpeg. Now I switched to your (latest) version and used the TSReader and indeed channel switching is only 2 seconds now! Same as in MediaPortal (I'm using only FTA channels with DVB-C, Terratect Cablestar HD2).

Because I thought it was related to the TVserver from MP, I changed to ForTheRecord. Now I can test both, and there is (almost) no difference in MP TV server or FTR. Which is great, as I almost went for betraying XBMC and go to the MP side; blu ray playback and just easy-of-use of XBMC stop me though.

Can you advise me what is the best tvserver? Which do you prefer? Ultimately I plan to use 3 DVB-C tuners and one DVB-S2.

- mylle - 2012-02-27 16:13

Now we just need the tsreader addon to be availible on the ATV2 Smile

Any update on this?

regards
Jacob

- margro - 2012-02-27 20:25

@jelleelco:
I'm myself a MediaPortal TV Server user. The functionality of the MediaPortal and ForTheRecord addons are roughtly similar.
Right now, ForTheRecord is a better choice when your client is a Linux machine or a Mac/ATV2.

@mylle:
Most of the MediaPortal tsreader code is already ported (thanks to help from Red-f who did it for the ForTheRecord addon).
However, I had no time yet to test it under Linux and MacOSX. I don't own an ATV2 or a Mac so I can't test it myself.

- mylle - 2012-02-27 22:37

margro Wrote:@jelleelco:
I'm myself a MediaPortal TV Server user. The functionality of the MediaPortal and ForTheRecord addons are roughtly similar.
Right now, ForTheRecord is a better choice when your client is a Linux machine or a Mac/ATV2.

@mylle:
Most of the MediaPortal tsreader code is already ported (thanks to help from Red-f who did it for the ForTheRecord addon).
However, I had no time yet to test it under Linux and MacOSX. I don't own an ATV2 or a Mac so I can't test it myself.

If you could compile an ATV2 build for me i will be more than happy to test it out Smile

Regards
Jacob

- jelleeelco - 2012-02-28 12:14

Hi Margro,
Thanks. Is there a specific reason you're using Mediaportal? I found FTR is a bit more stable, no glitches on startup, no "can't tune to channel" messages. But it might well be it has all to do with the ffmpeg reader. Right now using FTR and seems working ok (client and server on same pc, windows 7).

Now in the process of making the remote working as I want too...not a chance my wife will accept a half-working machine!