Resonable bitrate for exporting AVCHD footage

[eisbaer71]

Hello,

I read through many threads here, hoping to get an answer on this particular question, but since this was not the case I try to ask.

Source of my footage is Panasonic HMC-151, which delivers AVCHD files at 21Mbit/s mean and 24Mbit/s max bitrate using 720p50 mode.

I'm editing on Premiere CS5.5 and exporting the material to H.264/m2t files.
I made my own export preset and selected 24Mbit/s (VBR) as the maximum bitrate to match the max. camera bitrate. Output looks quite good.

If I look at the premiere or mainconcept encoder presets, they typically have 8...11 Mbit/s as the default export
bitrate for H.264/bluray, so I wonder if I'm wasting file size by using a too high output bitrate ???

I did some tests with 8Mbit/s instead of 24 Mbit/s and if I compare the results in full resolution there is almost no or no difference at all visible,
but I know that it also depends highly on the source material, kind of scenes, ...

Therefore the question comes down to that point:
Does it make sense to have the export bitrate as high as the camera bitrate or does this only
waste disk space ?

Thanks,
Markus

 

[JeganRX]

Since you're using Adobe Media Encoder, I'd always recommend encoding on the high side, so long as your hard drive permits it. AME has a particularly inefficient H.264 encoder (As does Apple), so my ultimate advice, if you want to go down this path, is to use CRF mode in an x264 encoder. You'll end up with a smaller size, and possibly even better quality (versus a given Adobe bitrate).