BBC HD DSat bitrate dropping...

Discussion in 'Satellite TV, Sky TV & FreeSat' started by `BK, Apr 27, 2007.

  1. `BK

    `BK
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    I haven't watched anything on BBC HD for ages but someone just told me the bitrate dropped. "Surely not!" I cried, not when Sky just boosted theirs...

    Sure enough, it's at 16.4Mbit/s, down from 19.24Mbit/s. Looks like it happened a few days ago.

    I would be disappointed if this was a sign of things to come, or perhaps they're just playing around like they did with Freeview (I believe they dropped 1080i to a similar bitrate back when they did their tests there, while testing high/low bitrate 720p also).
     
  2. Lakeuk

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    I don't pay much attention to the bitrates, I like to watch the programmes :rotfl: I've dug out an short clip I had of the old preview to compare to the new one.

    New preview
    1920x1088 384kbps 48kHz - averaging 16.4MBit

    Old preview
    1440x1088 384kbps 48kHz - averaging 18.8MBit

    to be expected after all it is a test channel
     
  3. Giblets2

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    It's not necessarily a bad thing, they could have bought some new, better encoders so it doesn't need as much bandwidth and saves our disk space as well! I may be being optimistic here but Sky definitely have plans in that direction.
     
  4. GaryJLynch

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    out of interest, how do you check the bitrate?

    cheers
    Gary
     
  5. Lakeuk

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    I watch it on my PC using dvbviewer which displays the rate
     
  6. TCM2007

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    It's a test channel; would be odd if they didn't test different bitrates!
     
  7. J Roadley

    J Roadley
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    There does seem to of been a dip in the bitrate last couple of days:

    [​IMG]
     
  8. Starburst

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    Yep, if we are still getting the current bitrates this time next year then Tandberg (and whoever supply the BBC) should be shot for not being to supply H.264 encoders that provide good PQ at bitrates that mpeg2 can not match.

    It's bizzare that some of the better HD examples from the US are at similar bitrates as ours but use mpeg2.
     
  9. `BK

    `BK
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    From what I've heard the encoders the Beeb use (not Tandberg IIRC) had an update at the same time. So maybe it'll be the same PQ despite the bitrate drop. Honestly there's been nothing I want to watch recently, guess I'll check out Hustle on Thursday though.
     
  10. xavster

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    Watched the Coast from the Air thing yesterday. Thought the PQ was pretty ropey. Certainly worse than the previous episode I saw.
     
  11. buseng

    buseng
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    Last of the summer wine was one the best HD quality programmes shown, certainly the last couple of episodes I saw on BBC HD. Tonight's episode looked really crap though, nowhere near as much detail, more like glorified SD.
     
  12. StevenBagley

    StevenBagley
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    That's probably source related... I'm assuming they haven't moved onto the new season (shot on the Viper) yet, and so the later episodes use a different camera profile to the earlier ones (the earlier ones looking much nicer).

    Steven
     
  13. CLH

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    Last night's "Green Green Grass" was breatktaking. Well the 20 seconds I watched anyway. :D
     
  14. Jaycee Dove

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    I think this is true.

    We watched all the Last of the Summer Wine episodes when BBC HD showed them a few months ago at their maximum bit rate.

    There was a very obvious difference in PQ between the older ones and the more recent ones shown for the first time.
     
  15. `BK

    `BK
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    Capped Hustle and flicked through it - unfortunatly there are a few places where you can start to see the effects of the lower bitrate. No doubt the noise of the show is intentional but it's not being fully retained in places and starts to break down into blocks. Despite the trial status I hope they take note like they did with the Freeview tests and bump it back up again.
     
  16. Digiman

    Digiman
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    I dont know if its a coincidence but when I now record BBCHD with DVBviewer I cannot play it back and Haali will not accept it either - "unknown error"

    Must be a coincidence. Anybody?
     
  17. StevenBagley

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    Yup I'm having the same problem getting things to playback it seems Mediaplayer classic is reading the wrong resolution out of the H264 stream...

    The problem isn't just the bitrate drop, that'd be pretty much insignificant if they weren't trying to compress 1.5x as much data (it's now a 1920x1088 stream instead of 1440x1088 -- a crazy thing to do as there is only one programme on the channel that can possibly benefit from the extra res and that's the new series of LAst of the Summer Wine and I bet the masters they use for that are 1440x1080 HDCam anyway).

    Steven
     
  18. BertM

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    There's a new DVB source filter for DVBViewer available from the customers download area which corrects invalid stream recognition. BBC-HD is still 1440 * 1088 as it always was...

    Also, to play back a recorded BBC-HD stream in DVBViewer you should try the new DVBViewer beta version, which plays back the video fine, unfortunately without sound (at least, on my setup).

    regards, Bert
     
  19. Digiman

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    Thanks StevenB and BertM. I may just get to the bottom of the problem quicker than I thought.

    DVBViewer is showing the stream as 1920x1088 but H264 parameter reader is showing 1440x1088.

    My problem looks like haali splitter does not understand the stream so I cannot convert it to mpg using Xmuxer. It says the file is unsupported. I need to convert it to watch it on my standalone media player (STB).

    BertM - Is this a new thing 'cos it worked fine before (1 week ago). Do you know what is wrong with the stream?

    BertM - Your sound problem I think is maybe discussed here. http://www.dvbviewer.info/forum/index.php?showtopic=18449&pid=135163&st=0&#entry135163

    I think it should resolve my problem. Naughty BBC.
     
  20. BertM

    BertM
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    Digiman, thanks a lot! I didn't notice that thread yet...

    As others mentioned, I also noticed problems with BBC-HD playback about a week ago or so. I really don't know what they've changed but the programmer of the DVBViewer source filter mentioned something about "additional high profile header values".
     
  21. Digiman

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    No problem BertM. I have my own thread going on in that forum (MarkR Newbie section "stopped working") and they directed me to it. You may want to try DVBViewerGE it works well for me. I am not sure the earlier thread will fix your problem but it might explain it.
     
  22. J Roadley

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    Jools Holland doesn't look as good as it has done... :(
     
  23. Silver Serpent

    Silver Serpent
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    The bitrate seems to a be a bit lower today on BBC HD judging by the PQ on last of the summer wine. It's not as good as it was yesterday.

    Anyone else notice this?
     
  24. linowsat

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    The bitrate is unchanged over the last ten days. It's still about ~16Mbit/s.

    Regards
    LinowSat
     
  25. J Roadley

    J Roadley
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    But has been ~18Mbit/s.

    :rolleyes:
     
  26. linowsat

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    Ok, you are right! And before ~18Mbit/s it has been over 19Mbit/s

    [​IMG]

    Cheers
    Oliver
     
  27. Gae

    Gae
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    I only get sound but no picture when I play back ts files in DVBViewer too. The solution I found was to upgrade my ts player to version 1.8 and that plays them fine.

    Gae
     

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