Mpeg4 vs Mpeg2 bandwidth?

[ajohnson]

Here's a question. Is there enough bandwidth on 61.5 or 129 to run all these new HD channels at a decent quality level under MPEG2, or are the channels going to be piss-poor until they switch to MPEG4?

My own primitive tests in encoding show MPEG4 to be at least half the bandwidth/size of MPEG2, although I read something that said a MPEG2 signal at 5mbps was the equivalent of an MPEG4 signal at 1.8mbps, going by peak signal to RMS noise ratio.

All I know is a 50mb mpeg2 video file was about 25mb in mpeg4, and I couldn't visually tell the difference between them.

Hopefully there's plenty of bandwidth, and the switch to mpeg4 will free up more, making room to add more "compelling" hd programming.

 

[Scott Greczkowski]

The VOOM channels are running at slighty lower quailty because of a fiber issue which they hope to have corrected after a second fiber line is installed (a few months away)

All other channels are being broadcast at their full resolution.

 

[BFG]

well until they actually start using MPEG4, the bandwidth and transponder usage is still the same

 

[Scott Greczkowski]

At the moment they are getting 3 HD channels to 1 transponder, with MPEg4 they are getting 4 channels on 1 transponder, which is not the gain they are looking for.

 

[ajohnson]

Thanks Scott, that sounds more like what I wanted to know. I guess I didn't quite word my question right. If I've read the boards right, on 2/1 there are supposed to be 6 or so more hd channels available, which will temporarily be MPEG2 but will be switched to MPEG4. If they get their desired bandwidth (2x?) I'd expect them to be able to open up 6 more hd channels after the switch, however your info puts that number at 2 channels, with the current software.

I suppose my question is really, how full are the transponders at 129 & 61.5? If they are maxxed out, then the only way to get more channels is to screw with the bitrate, which would be bad. If there is room for growth, then that is good

I could probably figure this info out myself by using Lyngsat or something, but I have a hunch that other's may not realize the size difference between MPEG2 & 4, and may want to know the answer too.