My Humax Forum » Freeview SD » PVR 9150T, 9200T, 9300T

9300T - Jumps during playback

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    pmb

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    I have already posted several times on this topic but it continues to drive me crazy and I just wanted to have another rant basically! I have spent much of this weekend watching recordings of films and it has happened on every one of them but I think I have found a pattern. Scenes which involve lots of bright action and sound are fine but dark, quiet scenes are the problem (and of course they are usually the ones with the important dialogue which you then miss). In old analogue days if there was a weak signal the picture would roll. In digital terms if we think in terms of texture - lots of action/sound is "rough", something to lock onto. Dark/quiet is "smooth". Every time a smooth patch is reached the machine skids like on ice.
    This may be total nonsense and I am not sure how it helps us solve the problem but I would be interested to hear whether anyone else can relate to this theory. If nothing else it may help me decide which programmes to record on Humax and which to use the Sky box for.

    | Mon 25 Jan 2016 9:48:29 #21 |
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    countryman

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    It could well be an explanation. Despite sending a plethora of information to Channel 4 I never got any feedback from them as to why all their channels have this problem with older PVRs with slow CPUs. I fixed it by buying a secondhand DTR YouView box. Such a delight to use. Fast. responsive. Excellent picture quality (even on SD). And I can record films knowing that they will playback.

    Also I don't have to restrict how many mux's I can tune to because of insufficient memory in the 9300 to store the EPG properly.

    Wanna buy a cheap 9300 as a spare ?

    | Mon 25 Jan 2016 9:53:02 #22 |
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    stevie-ji

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    pmb - 7 months ago  » 
    I have already posted several times on this topic but it continues to drive me crazy and I just wanted to have another rant basically! I have spent much of this weekend watching recordings of films and it has happened on every one of them but I think I have found a pattern. Scenes which involve lots of bright action and sound are fine but dark, quiet scenes are the problem (and of course they are usually the ones with the important dialogue which you then miss). In old analogue days if there was a weak signal the picture would roll. In digital terms if we think in terms of texture - lots of action/sound is "rough", something to lock onto. Dark/quiet is "smooth". Every time a smooth patch is reached the machine skids like on ice.
    This may be total nonsense and I am not sure how it helps us solve the problem but I would be interested to hear whether anyone else can relate to this theory. If nothing else it may help me decide which programmes to record on Humax and which to use the Sky box for.

    Yes, I have to say this has been my feeling, too. It seems to be some kind of synchronisation problem - as I think the sound and video are transmitted and recorded separately.

    My experience is certainly that the dark and/or quiet scenes are problematic - but why this would be the case, I really don't know. I would have thought the two tracks would be synchronised digitally - on a time-code, but apparently not.

    I get it most on Film 4 - also More 4 - and this made me suspect that it might be the broadcast, rather than my hardware, but like you, I firmly believe it is the nature of the program, not the channel.

    I can't see any solution, other than to replace the hardware, which has numerous other problems, which I won't go into here - but the stuttering playback is certainly the most infuriating.

    I am now thinking of replacing my 9300T with a free-sat system - but I'm a little wary, as the obvious choice would appear to be another Humax.

    I wonder if perhaps it's not necessary to switch to satellite, but just to get a new terrestrial box. Perhaps a new machine, like the 2000T, may have overcome the numerous teething problems of the 9300T - if indeed they were 'teething problems'. I would be interested to hear opinions, but I do remember doing my research before buying the 9300T - and it had extremely good reviews.

    | Wed 14 Sep 2016 11:20:08 #23 |
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    countryman

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    I had a brief flurry of communication with Chanel 4 towards the end of 2015 and your post reminds me that I ever ever got a reply from their techies after all the to'ing and fro'ing by them asking for more information, type of PVR, what film etc.

    I am convinced that it is down to the codecs and type of film material (low-key lit scenes, for example) and basically a, now, low-powered CPU in the Humax being asked to do more then it is capable of. Let's face it. As well as decoding the video signal, it also has to do a lot of housekeeping in the background, managing all those muxes with those lousy shopping channels. Basically it runs out of steam.

    I bought a fairly new Humax Youview and have been quietly impressed with it especially the ability to view stuff streamed over the internet. My double router setup seems to work well and also gives me better security.

    | Wed 14 Sep 2016 11:30:13 #24 |
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    stevie-ji

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    countryman - 24 minutes ago  » 
    I had a brief flurry of communication with Chanel 4 towards the end of 2015 and your post reminds me that I ever ever got a reply from their techies after all the to'ing and fro'ing by them asking for more information, type of PVR, what film etc.
    I am convinced that it is down to the codecs and type of film material (low-key lit scenes, for example) and basically a, now, low-powered CPU in the Humax being asked to do more then it is capable of. Let's face it. As well as decoding the video signal, it also has to do a lot of housekeeping in the background, managing all those muxes with those lousy shopping channels. Basically it runs out of steam.
    I bought a fairly new Humax Youview and have been quietly impressed with it especially the ability to view stuff streamed over the internet. My double router setup seems to work well and also gives me better security.

    I suppose it couldn't hurt to delete all the unwanted channels - and I'm more or less resigned to replacing the unit anyway.

    I don't currently have my own internet connection - I piggy-back my neighbour's wi-fi - so I don't think I need YouView at present. What you say about the processor, though, is interesting - I haven't seen this info in the specs. If I just upgraded to a newer model I assume the CPU would be more powerful, but it would be good to see this quantified.

    | Wed 14 Sep 2016 12:07:56 #25 |
  6. Biggles

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    Someone on one of the forums discovered that if you switch soundtrack (second button from left second row down under the slide, speaker symbol) the jumping problem went away. This is not of much use to us really as you end up with no audio but should have been a useful pointer for Humax to solve the problem.

    | Wed 14 Sep 2016 12:21:46 #26 |
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    countryman

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    Deleting channels won't help you. It's the managing of the mux's that consumes the CPU cycles. And as a side issue the 9300 (and possibly other models) hasn't got enough room to handle the EPG properly anyway because of the multiplicity of channels and so what I am writing below will help that problem as well.

    You have to decide which channels and therefore which mux's you can do without. Then delete your channels/muxs already tuned to, and do a manual tune to the muxs you have chosen to keep.

    NB Still no guarantee that it will cure your problem.

    | Wed 14 Sep 2016 12:49:59 #27 |
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    Erica Clarke

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    What is a mux? I am a country girl. Don't understand all these technicalities, only that I am fed up with my humax jumping forward! If I can work out how to do it, will it help?

    | Wed 14 Sep 2016 12:55:24 #28 |
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    Martin Liddle

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    countryman - 29 minutes ago  » 
    I am convinced that it is down to the codecs and type of film material (low-key lit scenes, for example) and basically a, now, low-powered CPU in the Humax being asked to do more then it is capable of. Let's face it. As well as decoding the video signal, it also has to do a lot of housekeeping in the background, managing all those muxes with those lousy shopping channels. Basically it runs out of steam.

    I think you will find that in all the Humax products that the CPU does not do any decoding; it is all done by special purpose decoding chips. My best guess (give that the problem did not occur for some time after the 9300 was made available) is that the broadcaster started to use a new type of encoding that was in the broadcast specifications but hadn't previously been used and there is some sort of bug in the decoding hardware.

    | Wed 14 Sep 2016 12:57:03 #29 |
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    Martin Liddle

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    Erica Clarke - 2 minutes ago  » 
    What is a mux?

    A mux is a collection of digital channels amalgamated togther for broadcasting and then split out again by the Humax. Typically your Humax will be receiving five multiplexes and reducing the number of multiplexes to three or four will improve the responsiveness of the Humax but mean certain channels are not available via the Humax.

    only that I am fed up with my humax jumping forward! If I can work out how to do it, will it help?

    NO. There is as far as I am aware no fix for the jumping forward problem.

    | Wed 14 Sep 2016 13:02:36 #30 |

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