It’s been a while since my last analysis of the Freeview services on air in Sydney – in fact, the last time I did it was after SBS moved to MPEG-4 for its HD services back in 18th April 2017. Part of the reason for this is simply because of a change of habit – we no longer consume as much TV as we used to. Another reason is that I had moved into a different location, which had poor reception as a consequence. But as I recently returned back to my other house to fix a few things, I thought I’d bring along my TBS 5220SE and record some multiplex .ts files to analyse on my return home.
Multiplexes on the Air & Their Constellations
From the test location, doing a whole scan of the band, it is fairly quiet except for the strong signals from Gore Hill, comprising of five DVB-T multiplexes as expected. Another hump is seen above 750Mhz and represents the new LTE base stations using the “digital dividend” spectrum (e.g. Telstra 4GX, Optus 4G Plus).
The multiplexes all averaged about 37dB SNR which is a lot better than at my regular location. Of note is that all of them have the same DVB-T transmission parameters of 64QAM, 3/4 FEC, 8K FFT, 1/16 Guard Interval, thus all broadcasters have the same amount of bandwidth to deliver their services (23.050Mbit/s). Constellation plots are fairly well resolved with a sprinkling of noise which may be due to non-linearities of the splitting amplifier that I had used (e.g. when encountering impulse noise).
Overall, the signal strength was adequate enough to record 32GiB TS files (just over three hours) on 27th December 2018 for averaged bitrate analysis.
Summary of Services
The new service summary table is as above. Key changes are highlighted in red and summarised below:
- The first DSM-CC PIDs previously allocated have mostly been removed, so where a broadcaster had two streams, now they have just one, etc.
- Channel 7 has gained Channel 74 7food network, which broadcasts in MPEG-4 H.264 [email protected] 640x576i with MPEG-4 HE-AACv2 Stereo audio, similarly to RACING.COM, which will require more modern televisions to receive. The quality offered is likely to be limited.
- SBS’s loss of the Food Network branding results in their channel being changed to SBS Food. SBS also offers their DAB digital radio offerings over their TV multiplex, especially gaining SBS Chill (replacing Radio 3’s PMT entry), SBS Radio 3, SBS PopDesi and SBS PopAsia – the latter two using MPEG-4 HE-AACv2 Stereo encoding for higher bitrate efficiency.
- Channel 9 has changed EXTRA to be called Your Money. Seems like an odd rebranding.
- Channel 10 have renamed most of their services, opting for the digits “10” instead of Ten possibly to try and show up higher if sorted alphabetically. The naming is rather nondescript – “BOLD”, “Peach” … am I expecting to see peaches on TV now?
- ABC has also renamed ABC News 24 to just ABC NEWS, with ABC 2 becoming ABCComedy/Kids. The radio servies get a bump up in their bitrate to 256kbit/s.
The per-PID rates are provided in the image above.
Multiplex utilisation appears to have improved, with Nine, Ten and SBS being very close to filling their multiplex and Seven being quite acceptably close. The only broadcaster not making full use of their multiplex seems to be ABC which has left almost enough bitrate for a whole new service. I wonder if that is their eventual intention?
TV Service Bitrates
The above graph summarises the TV service total bitrates sorted descending. HD services are highlighted in light green, while MPEG-4 SD services are in teal green. MPEG-4 or AC3 audio is highlighted in purple to distinguish from the baseline MPEG services.
On the whole, it seems that 10 HD has a sizeable lead in bitrate over all other broadcasters’ services. HD services occupy mostly the higher bitrate echelons, with the exception of ABC which seems to prioritise its SD bitrate ahead of its HD service bitrate.
Rather unexpectedly, the newly launched 7food network occupies bottom spot for total service bitrate – even falling behind RACING.COM and all the “rubbish” shopping channels. This suggests that the channel may not have significant viewership or is not of a high priority for the network at this time.
Variations between most mainstream MPEG-2 channels don’t seem to be too significant, with some secondary channels enjoying higher bitrates than the primary channels (as those may also be simulcast in HD). The progression to MPEG-4 technology seems to be slow and cautious as viewers take time to update to newer TVs (or perhaps, ditch the whole broadcast TV paradigm altogether).
Bitrate Evolution Trends
It seems that over time, the bitrates for Seven have mostly stabilised with only minor changes. The exception would be 7HD Sydney which launched with high bitrates, only to have that clawed back for the rise of 7flix, 7food network and RACING.COM.
A look at SBS shows barely any bitrate movement at all compared to previous measurements. If anything, it seems any differences may just reflect statistical multiplexing and the type of content being aired at the time.
Nine’s bitrates have mostly remained stable as well, with a slight loss in the main SD channel being offset by gains in 9Life and 9HD Sydney.
Network Ten’s bitrates seem to have only seen minor changes as well, with 10 BOLD getting a bump up, at a slight cost to the remainder of the channels. Again, we might be seeing content-based effects causing minor skew in the values.
Finally, ABC sees a surprising drop in ABC NEWS and ABC HD bitrate, where the others mostly remain stable. Due to the inefficient multiplex utilisation, this bitrate reduction has only led to the emission of null padding packets in the multiplex.
Freeview TV is becoming less and less a part of my life, thus this analysis comes well overdue. Due to a fortuitous situation which allowed me to access a good quality signal, I took the opportunity to make some recordings for analysis.
While there have been a few minor renaming of services and the launch of a new channel, there seems to be less of an emphasis on quality as we continue to squeeze more from our limited bandwidth while using older MPEG-2/MPEG-1 suite of baseline codecs and DVB-T modulation to ensure maximal compatibility. HD MPEG-4 services which launched with high bitrates, enabled by the “large” bitrate allocation formerly needed to carry HD MPEG-2 services, have given way to more moderate allocations in order to squeeze in another SD MPEG-2 service.
The big disappointment seems to be 7food network which has launched using MPEG-4 codecs (limiting viewer access to some degree) while also being extremely deprived of bitrate even compared to shopping channels.
But in a world with increasingly good internet access, live streaming possibilities coupled with video-on-demand catch-up, the reasons to maintain a TV and aerial are beginning to diminish. Even satellite and pay TV providers have embraced the move to IPTV, so it seems that Freeview may be living on borrowed time.