What is 18mbps h.264 comparable to in MPG2 ?

[JonRead]

This will sound an odd question, but I capture in 18mbps h.264 1080i, and I need to convert them to mpg2 HD without any loss of quality. This is so I can edit them. What bitrate should I choose in MPG2 to make sure it is of same quality as source ? Thanks.

[komarovsky]

i'm not sure if mpeg 2 has a lossless mode, so you will have some loss of quality

[foxyshadis]

The more you can give it the better; 30 mbps would probably be a minimum but it'll probably take 40-50 to get to where you can't see any difference from the source at all. That's the downside any time you convert formats.

[Audionut]

This is so I can edit them.

Why not use lossless to edit?

Even better, capture in lossless, edit, then save to desired format.

[Blue_MiSfit]

Yes. 50mbps would be my baseline for transparency. I get MPEG-2 deliveries in CBR 80mbps intra-only, and they look damned good, most of the time. That being said, the sources for these deliveries are usually HDCAM-SR or D5 HD tapes, which are very high quality to begin with. Your 18mbps H.264 1080i came from where?

[JonRead]

Thanks for all the advice. In answer to the above question, the source is from UK TV broadcasts.

[Blue_MiSfit]

Gotcha. So it's a stream copy, right? Not an analog capture via component?

~MiSfit

[JonRead]

Yep, direct on the PC from source, so I thought I best capture at source then edit in MPG2 due to hardly any decent h.264 editors being out there, but I didn't want to lose quality in the conversion. I chose MPG2 as then I can use tools like Video Redo to edit. I will select 50mb to make sure it is as lossless as possible from source.

[Blue_MiSfit]

If you're looking to do simple trim editing, AviDemux might be able to operate on the transport stream.

~MiSfit