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BT Sports 1 and 2 on DTT technical details

DWA9ISDWA9IS Posts: 10,557
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As the title I would like to know if anyone knows anything about them other than they are AVC/MPEG4 and are nearly 2Mb bitrate each!
Are they 720x576 res ect?

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    BangersBangers Posts: 3,649
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    They are MPEG2, not MPEG4.
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    Tim_BishopTim_Bishop Posts: 64
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    Bangers wrote: »
    They are MPEG2, not MPEG4.

    No, they *are* MPEG4. they were given special permission to broadcast in mpeg4 because the only boxes to recieve the channels would be the BT Vision boxes.

    this was changed when BT 1 and 2 took over last year on DTT.
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    kevkev Posts: 21,075
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    Not sure of the resolution but http://www.digitalbitrate.com/dtv.php?mux=ARQB&pid=27328&live=9&lang=fr shows the bitrates...
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    DWA9ISDWA9IS Posts: 10,557
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    kev wrote: »
    Not sure of the resolution but http://www.digitalbitrate.com/dtv.php?mux=ARQB&pid=27328&live=9&lang=fr shows the bitrates...

    Yes Ive seen that site before and yes I saw on there that the bit rate is 1.9Mb so apx the 2Mb that I thought!

    Im still trying to find out about the res though!
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    popeye13popeye13 Posts: 8,573
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    Id imagine the res is the same as the Sky Sports channels were, which was 544 x 576i
    Saying that, the PQ wasn't bad IMHO. Not seen BT Sport channels on DTT though.
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    DWA9ISDWA9IS Posts: 10,557
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    popeye13 wrote: »
    Id imagine the res is the same as the Sky Sports channels were, which was 544 x 576i
    Saying that, the PQ wasn't bad IMHO. Not seen BT Sport channels on DTT though.

    They effectively have double the bandwith of a 544x576 res channel on those MUXs though, as they are AVC/MPEG 4 and the 544x576 channels that share the MUX with them are MPEG 2, like all other SD channels in the UK.
    So with that in mind it would be very odd indeed that they would be 544x576 but hay ho if they are they are.
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    popeye13popeye13 Posts: 8,573
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    lotrjw wrote: »
    They effectively have double the bandwith of a 544x576 res channel on those MUXs though, as they are AVC/MPEG 4 and the 544x576 channels that share the MUX with them are MPEG 2, like all other SD channels in the UK.
    So with that in mind it would be very odd indeed that they would be 544x576 but hay ho if they are they are.

    They may have gone to 704 or 720 x 576i but they were 544 in the Sky sports days.
    Possible BT want better PQ and if technically possible as you say because the available bandwidth, they may very well be at 704 or 720 x 576i
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    kevkev Posts: 21,075
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    popeye13 wrote: »
    They may have gone to 704 or 720 x 576i but they were 544 in the Sky sports days.
    Possible BT want better PQ and if technically possible as you say because the available bandwidth, they may very well be at 704 or 720 x 576i

    The Sky Sports channels were in MPEG2

    The BT Sports channels are around the same bit rate but H264 - this means the picture will be a higher quality so it's a pretty good assumption they will be in a better resolution too. Alas as the streams are encrypted you can't see the resolution of the video.
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    DWA9ISDWA9IS Posts: 10,557
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    popeye13 wrote: »
    They may have gone to 704 or 720 x 576i but they were 544 in the Sky sports days.
    Possible BT want better PQ and if technically possible as you say because the available bandwidth, they may very well be at 704 or 720 x 576i
    kev wrote: »
    The Sky Sports channels were in MPEG2

    The BT Sports channels are around the same bit rate but H264 - this means the picture will be a higher quality so it's a pretty good assumption they will be in a better resolution too. Alas as the streams are encrypted you can't see the resolution of the video.

    The interesting thing is as AVC/MPEG 4 halves the bit rate for the same quallity as MPEG 2, if they were theoretically in MPEG 2 with the same quality of bitrate they would have 3.8Mb! Thats as much as the BBC give BBC 1 and 2 on BBC A MUX!
    So by that they certainly should be the same res and quality as BBC 1 SD!
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    DWA9ISDWA9IS Posts: 10,557
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    Do BT vision boxes need viewing cards? If so could someone possibly try it out in a PC with a card reader and the right DTT viewing software?
    I think that would be the only way to get the right information about the res of this channel!
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    BangersBangers Posts: 3,649
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    Tim_Bishop wrote: »
    No, they *are* MPEG4. they were given special permission to broadcast in mpeg4 because the only boxes to recieve the channels would be the BT Vision boxes.

    this was changed when BT 1 and 2 took over last year on DTT.

    Thanks, I never knew that.
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    Tim_BishopTim_Bishop Posts: 64
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    BT Vision boxes no longer require cards.

    although the signal for DTT comes through the aerial, the authorisation comes through the broadband.

    its a very similar process for YouView and the Multicast channels.
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    DWA9ISDWA9IS Posts: 10,557
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    Tim_Bishop wrote: »
    BT Vision boxes no longer require cards.

    although the signal for DTT comes through the aerial, the authorisation comes through the broadband.

    its a very similar process for YouView and the Multicast channels.

    So are you saying their is no way to tell?
    I suppose that someone would have to contact BT themselves to find out, but it would need to be someone who is involved with the playout of the channels I suppose?
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    DragonQDragonQ Posts: 4,807
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    I'd imagine they're 704x576i (or 720x576i) if the bit rate is that high (for AVC). Would be a waste otherwise. They must have a fixed bandwidth allocation because statistical multiplexing wouldn't work between different codecs. They can probably shift the available bandwidth between the two channels as required though.
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    kevkev Posts: 21,075
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    DragonQ wrote: »
    I'd imagine they're 704x576i (or 720x576i) if the bit rate is that high (for AVC). Would be a waste otherwise. They must have a fixed bandwidth allocation because statistical multiplexing wouldn't work between different codecs. They can probably shift the available bandwidth between the two channels as required though.

    It looks like both BT Sport 1 and BT Sport 2 are stat multiplexed, not only with one another but with the services on the rest of the multiplex.

    http://kjs.me.uk/3rdparty/digitalspy/btsport.png
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    DragonQDragonQ Posts: 4,807
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    Hmm fair enough. Not sure how they'd do that.
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    DWA9ISDWA9IS Posts: 10,557
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    Thanks for the info guys
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    pete taylorpete taylor Posts: 1,977
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    **** Deleted - Wrong Quote ****
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    pete taylorpete taylor Posts: 1,977
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    Tim_Bishop wrote: »
    BT Vision boxes no longer require cards.

    although the signal for DTT comes through the aerial, the authorisation comes through the broadband.

    its a very similar process for YouView and the Multicast channels.



    So why does both BT Sport 1 & 2 go blank when I remove the card?
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    DWA9ISDWA9IS Posts: 10,557
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    So why does both BT Sport 1 & 2 go blank when I remove the card?

    So it may well be possible to put the card in a reader that can decode BT vision cards and use a DTT receiver card on a PC and decode the BT Sports channels?
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