Back in March this year I set out a list of the video and audio bitrates for digital TV. Since then new channels have been added and some of the stations have reallocated the balance of their available bandwidth.
To gather this data, over the last few days I have recorded at least six hours, in three separate chunks, from each station onto a Topfield PVR. 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 Topfield adds into its recording stream (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 | MPEG 2.0 | 256 | 720 x 576i | 4.97 |
| ABC2 | 22 | MPEG 2.0 | 256 | 720 x 576i | 3.91 |
| ABC3 | 23 | MPEG 2.0 | 256 | 720 x 576i | 3.95 |
| ABC News 24 | 24 | DD 2.0 | 448 | 1280 x 720p | 7.95 |
| SBS ONE | 3 | MPEG 2.0 | 192 | 720 x 576i | 4.19 |
| SBS TWO | 32 | MPEG 2.0 | 192 | 720 x 576 | 3.77 |
| SBS HD | 30 | MPEG 2.0 | 192 | 1280 x 720p | 9.48 |
| SC10 Canberra | 5 | MPEG 2.0 | 256 | 720 x 576i | 6.03 |
| One HD Canberra | 50 | DD 2.0 | 448 | 1440 x 1080i | 14.40 |
| PRIME Canberra | 6 | MPEG 2.0 | 256 | 720 x 576i | 5.07 |
| 7TWO on PRIME | 62 | MPEG 2.0 | 256 | 720 x 576i | 4.81 |
| 7mate on PRIME | 63 | DD 2.0 | 256 | 1440 x 1080i | 10.04 |
| WIN Canberra | 8 | MPEG 2.0 | 384 | 720 x 576i | 4.97 |
| Canberra GO | 88 | MPEG 2.0 | 384 | 720 x 576i | 4.52 |
| GEM Canberra | 80 | DD 2.0 | 192 | 1440 x 1080i | 9.63 |
Interesting change: When switching to GEM Canberra, WIN reduced the Dolby Digital two channel audio bitrate from 448kbps to 192kbps. If they are going to persist with 2.0, then that makes sense. But perhaps they should also reduce the MPEG2 audio stream in their other channels from from 384kbps to 192kbps. That would allow a few more bits for the video.
ABC3 only runs a static logo (with music) after about 9pm until the next morning. The video bitrate at these times is just 1.98Mbps.
5 Responses to Video bitrates for digital TV stations – October 2010