Collision of Frame Rates Internationally

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aquasmash
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Joined: Sun Feb 11, 2018 5:19 am

Collision of Frame Rates Internationally

Post by aquasmash » Sun Feb 11, 2018 5:37 am

I live in Australia which has DVB-T as the Free-to-Air TV broadcast standard and broadcasts in MPEG 25fps . When I'm watching the news and they do a 'live' cross from or a story made in, the US, the picture always seems grainy or slightly soft. I don't think it's satellite/internet connections as Eurovision, the Tour De France and other international events generally always seem crystal clear on the TV. I think it's more the American ATSC 30fps causing things to look a little out of whack as well as interlacing possibly being out of time/sync. I know this is sort of based on the hertz rate in every country, but other standards might effect the result as well. Can anyone explain this abnormality?

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davek
Posts: 181
Joined: Sun Aug 02, 2009 7:28 pm
Location: Sydney, Australia

Re: Collision of Frame Rates Internationally

Post by davek » Sun Feb 11, 2018 7:26 am

First up, Tour de France and Eurovision are produced natively at 25 frames per second, and at minimum in HD (Euro might be 4K now). Since these are "big ticket" items they will be delivered internationally in high quality. Hence they look good on Aus HD channels.

Contrast this to news, where immediacy is more important. Converting from 29.97 frames per second to 25 (in real time) can usually be done by dropping frames, and more fancy converters will attempt to interpolate between dropped frames to make it look less obvious. If the picture looks soft, either the source material might only be available in SD resolution, or is being heavily compressed to fit down a low bandwidth path (in real time, ie satellite) or small file size for offline transfer.

coremans
Posts: 12
Joined: Thu Feb 15, 2018 8:36 am

Re: Collision of Frame Rates Internationally

Post by coremans » Thu Feb 15, 2018 9:02 am

For your info. The Tour de France live is transmitted to SBS Australia in 32Mbit/s HD Mpeg4
The lives from US are not only frame converted but also the source is more often a LTE 4G connection with cheap baseline profile codecs.
When using a decent frame rate converter such as Snell then this will not cause any visible bad quality

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