Picture quality on Freeview

My understanding is that the ‘quality levels’ are dynamic and are adjusted depending on what is going on in each channel within a mux. In fact the quality adjustments are often done manually by a human in response to audience feedback.

So if someone phones up the control centre and says ‘the picture on the “food network” is looking a bit blocky’, a technician might manually dial down the bandwidth available to sky news to give the food network a bit more quality.

Therefore, if you are unhappy with the quality of Sky News, try phoning them up and complaining.

This is not my area of expertise however, and the above is just something I was told once by a video-expert. I cannot vouch for its veracity.

Sky News used to broadcast at 720×576, this changed last year to 544×576 and I suspect the bitrate has reduced to produce the poor images.

However compare the PQ of Sky News to 5* and it’s still miles better.

Wow – 544×576? That’s pretty grim in this day and age…

David: Yes, statistical muxing is a thing that happens but it’s done by machines, not humans. The idea is you have the codecs assess the complexity of encoding video and allow them to adjust their bandwidth utilisation within a mux to reduce or increase their usage. This all happens in realtime, and just means things are done more efficiently. It shouldn’t, in theory, result in significant quality loss – it should just result in a boost in quality where loss might have happened, assuming there’s a channel on the mux the bandwidth can be drawn from (ie something doing something relatively simple). I am not an engineer but I’ve been doing a lot of reading around the specs/research etc lately.

It depends on what set top box use as well. I have found that some boxes produce a worser picture than others.

Re. James’ original post. I can’t say I’ve really noticed. I have a Sony 32” TV with integrated Freeview tuner (I don’t have satellite or cable) – plus a Sony PVR/DVD recorder and a Humax Freeview HD box.

I live in a block of flats with a communal aerial system.

I understand that, before London DSO in April, Sky News was on a lower-power mux. While I got a good picture on my TV and PVR I would often get bad blocking and picture break-up on that mux’s channels when using the HD box. Since DSO all muxes are now running at full power and I have had no problems with reception on any channel.

Our communal aerial system has also been upgraded etc., which, of course, has also probably helped.

My only gripe with Freeview is that I can’t watch any Sky channels, Pick TV or Sky News, because if I do, my box consistantly crashes, so I have deleted them from my channel lists. It’s a Humax 9200 T by the way.

Brian, it sounds like your box can’t handle the MHEG (text/red button) that also is transmitted alongside those channels. This should also affect Challenge TV as well.

It does affect challenge as well. Don’t bother me coz there ain’t much to watch on them channels, just weird though.