Digital TV video bitrates – January 2013

Another two stations added to the free to air offerings. There seem to have been significant changes to some of the broadcasters’ bitrates, and indeed several have changed the resolution of their broadcasts.

To gather this data, on 2 through 4 January 2013 I  recorded at least six hours, in three separate chunks, from each station onto one of two Topfield PVRs. Then I whacked the minutes and megabytes into a spreadsheet, did the division and subtracted the audio bitrate. These figures probably overstate things a little, depending how much extra the Topfields add into the recording streams (not much, I imagine, because they are standard MPEG files), and the presence of subtitles. So, really, only the first two significant figures of the video bitstream should be considered.

Also, remember, this is in Canberra. The figures may well be quite different elsewhere. Our commercial stations still broadcast their HD as 1,440 x 1,080, for example.

If anyone would like to repeat the process in a major capital city, I’d be happy to email through the spreadsheet on condition that you provide the information back for publication here in due course.

Station Ch Audio
format
Audio
bitrate
(kbps)
Video
resolution
Average
video bitrate (Mbps)
ABC1 2 MPEG2 256 720 x 576i 4.56
ABC2 / ABC4 22 MPEG2 256 720 x 576i 3.98
ABC3 23 MPEG2 256 720 x 576i 3.81
ABC News 24 24 DD 2.0 256 1280 x 720p 7.94
SBS ONE 3 MPEG2 192 720 x 576i 3.00
SBS HD 30 MPEG2 192 1280 x 720p 8.43
SBS TWO 32 MPEG2 192 720 x 576i 3.03
NITV 34 MPEG2 192 720 x 576i 3.20
SC10 Canberra 5 MPEG2 256 720 x 576i 4.85
One Canberra 50 DD 2.0 448 1440 x 1080i 9.62
TVSN 54 MPEG2 128 544 x 576i 2.25
ELEVEN 55 MPEG2 256 720 x 576i 4.18
PRIME7 Canberra 6 MPEG2 256 720 x 576i 4.64
7TWO Canberra 62 MPEG2 256 720 x 576i 4.63
7mate Canberra 63 DD 2.0 256 1440 x 1080i 8.54
4ME 64 MPEG2 128 720 x 576i 2.21
WIN Canberra 8 MPEG2 384 720 x 576i 4.55
GEM Canberra 80 DD 2.0 448 1440 x 1080i 8.22
GOLD 84 MPEG2 192 480 x 576i 2.45
GO! Canberra 88 MPEG2 384 720 x 576i 4.09

Things to note:

  • ABC used to broadcast on ABC3 at a reduced 2Mpbs bitrate during the hours that it is closed overnight. Now it maintains the same bitrate overnight (the picture during these times is largely static panels with a little light animation on them). However from program to program there is a fair amount of flexibility in the bitrate, suggesting ABC still re-allocates the bandwidth available according to the balance of programming. It’s just that they allow too much for that near-static overnight stuff on ABC3.
  • SBS has made two big changes: it has added the NITV (National Indigenous TV) channel, and changed the resolution of its HD channel from 720p50 to 1080i50. The former has sucked quite a bit of bandwidth from the existing stations, reducing SBS One from 4.5Mbps last time to just 3Mbps.
  • Southern Cross Ten has added an advertising channel, TVSN, with a low audio bitrate and low resolution (544 rather than 720 pixels wide). A little of this channel’s resources has been drawn from SC10, the main channel, but most has come from the HD ONE Canberra, which has fallen from 11.46 to 9.62Mbps
  • Prime has reduced the average bitrate of its advertising channel, 4ME, yet at the same time bumped its resolution back to the original 720 x 576 from 544 x 576. It has retained the same lower audio bitrate, though, of 128kbps.
  • WIN’s GOLD channel has had its bitrate bumped up from an appalling 1.5Mbps to 2.45Mbps, although the resolution has remained the same at 480 x 576, a full third below the norm. It also has a too high audio bitrate of 192kbps. Indeed, WIN continues to waste lots of bits on audio for all its stations: 384kbps for the two SD ones and 448kbps for its HD station. Bringing the SD ones down to 192kbps would bring them into line with the bulk of 2.0 audio on DVD, and given that the HD is rarely if ever in 5.1 mode, 448kbps is a bit over the top. Changing to 192kbps all around, except for 128kbps for GOLD, would release about 0.7Mbps which could be spent on improving picture quality.
  • ONE Canberra remains the winner for HD bitrate, by a greatly reduced margin, at 9.62Mbps (the others are around 8.5Mpbs).
  • The winner for SD bitrate is SC10 Canberra on 4.85Mbps, down from 5.14Mbps.
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3 Responses to Digital TV video bitrates – January 2013

  1. Simon Reidy says:

    Thanks for such a comprehensive analysis once again Stephen. Although every time you do this, I grow that little bit more depressed about the pathetic state of DTV in Australia. I don’t even bother looking out for any native HD content any more it’s so few and far inbetween and over-compressed to hell anyway.

    I don’t have a USB or DTV Card in my PC or I’d be happy to analyse Hobart’s situation for you. Although I expect it’s almost identical to Canberra’s (the only difference being TDT = Channel 10 minus the prime time shows Southern Cross steals) and Seven Prime is still largely Southern Cross here which is a mixture of Seven and Ten content (predominantly Channel 7 content, but still taking popular shows from Ten and removing them from TDT) and usually replaces good shows with ‘Everybody loves Raymond’ repeats or the like.

    It’s Lso a total joke that we have ABC wasting bandwidth for pointless upscaled content on ABCnews24, when that should be an SD channel and ABC1 should switch to 720p at minimum to start showing all their BBC acquired content in something over than 576i.

    Apart from that I’ll continue to stick to Blu-Ray and illegal content downloading until I have the same legal options for acquiring content as they do in the US (whether over the air HD, cable, Netflix of Hulu). Thank goodness for 720p/1080p torrents.

  2. I’m pretty sure that stations were required to essentially mirror their analogue channel in SD by law. But once the analogue phase out has been completed this year, perhaps ABC can flip them around. The only problem is that this could irritate millions if their STBs and TVs fail to capture the changes automatically.

  3. Michael Cuddihy says:

    This is depressing but not surprising.

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