MPEG2 for broadcast - Data rates, quality?

I was asked to delivery a program that was originally 1080p, to MPEG2 SD for broadcast yesterday. I was pleasantly surprised that Compressor had a MPEG2 delivery presets for Program and Transport streams, and therefore I could bring in that compressor setting into FCPX and export directly.

All worked fine, but I was shocked at the time it took to encode and the size of resulting 4 minute clip was about 500MB. This is using Apple's built in 15 Mbps setting, which is also 2 pass and "best" VBR.

I was curious if anyone had any experience with using non 2 pass encoding and perhaps a lower data rate with MPEG2 streams that were destined for broadcast.

Thanks,

T.

Hey Tim,

You can safely lower the bit rate to 10-11 Mbps, some playout servers won't even accept higher bit rates than this. I haven't delivered MPEG-2 to stations for a while anymore, but I recall in the days we did we used 1 pass VBR or CBR all the time with very good results. Part of the long time it takes to encode is also due to the downscaling from 1080 to SD.

-Ronny

Thanks for your wisdom Ronny.

If I ever get another request for a MPEG2 stream, I'll lower that data rate.

So as I was tinkering around with MPEG2, I was frankly amazed at MPEG4 and h264. What is 500MB for a SD MPEG2 file, is a mere 53MB for a 720p of the same content with x264. Granted regular h264 would be around 140 MB, but still that is an incredible savings.

Yes MPEG-2 is certainly an outdated and very ineffective delivery format. That's why we never use it anymore. Most broadcast deliveries we do are now ProRes or DPP.

-Ronny