Q: (Aus only) SBS HD mpeg pixelation artifacts. Anyone else notice them lately? - Page 1
Forum section: electronics / general

author: wilfred
author_rank: Super Contributor
timestamp: November 30, 2015, 12:20:27 am
content: /.

author: yodhe
author_rank: Contributor
timestamp: November 30, 2015, 01:53:41 am
content: Yep. I have noticed the same artifacts myself. No clue as to why. On my crappy Toshiba LCD I can watch the interpolation happening over about 0.5 sec.

author: SeanB
author_rank: Super Contributor
timestamp: November 30, 2015, 04:38:20 am
content: Simply them trying to get too many different stations into a single multiplex. Data rate has to suffer on those with low priority, and if there are any HD channels on the multiplex they tend to show up as they really need the full bandwidth for best quality and robustness. You can always get it to show up by looking at a high def scene with either sports with fast panning ( motor racing, rugby with stadium roving cameras) where the grass turns into a green blur for the pan, where on a single multiplex it will show up every single blade of grass during the pan. Fashion shows will show the blocking with camera flash, which basically is a single frame of full white, then back to the room.

author: crispy_tofu
author_rank: Super Contributor
timestamp: November 30, 2015, 04:52:56 am
content: It's been happening for me on Channel 7 for some reason... Weird.The only change that I can think of recently is the Channel 9 HD channels, could that be the cause?

author: rs20
author_rank: Super Contributor
timestamp: November 30, 2015, 05:23:10 am
content: I assume terrestrial DVB capture devices can report the data rate allocated to each channel? It'd be fascinating to see these allocations change over time. Quick, someone write a cron job!!

author: Tim F
author_rank: Regular Contributor
timestamp: November 30, 2015, 05:28:32 am
content: Not a new problem. MPEG-2 is a pretty basic encoder and if you reduce the data rate too far something has to give. It's gotten a lot worse since every Australian broadcaster has decided that they should broadcast multiple standard definition channels and one 'HD' channel (1440x1080 interlaced, hardly HD...) over a band that was only ever intended to broadcast one 1080p channel.It would be interesting to see if they do change the data rates from time to time.

author: rs20
author_rank: Super Contributor
timestamp: November 30, 2015, 05:29:57 am
content: Are there any plans in progress to use better codecs? Obviously there's a problem with legacy receivers, but that's all the more reason to push for progress ASAP.

author: Tim F
author_rank: Regular Contributor
timestamp: November 30, 2015, 05:32:59 am
content: Quote from: rs20 on November 30, 2015, 05:29:57 amThere was talk about kicking community channels (e.g. Channel 31) off air, allegedly with the intention to test H.264 broadcasting. I haven't been keeping up to date with that story though so i'm not sure if they are going through with it or not.

author: Zero999
author_rank: Super Contributor
timestamp: November 30, 2015, 08:56:32 am
content: If this is what happens then what's the point of HD? Standard definition without the pixelation would be better.