Any experiences with 60p AVCHD internal vs 60i external ProRes HQ recording?

[Petr Volgemut]

Hi guys,
what are your experiences with a quality comparison (also in slow mo) of internal AVCHD 60p (or 50p in PAL countries) recording on FS700 vs external uncompressed or ProRes HQ 60i. 60p is better than 60i but uncompressed or ProRes HQ is better than AVCHD. I am asking because 60p external recording is not possible on Hyperdeck Shuttle 2 or Samurai (only 60i), it is possible only internally in AVCHD.
This question is not for owners of 60p external recoders:)

[Eric Olson]

Originally Posted by Petr Volgemut

Hi guys,
what are your experiences with a quality comparison (also in slow mo) of internal AVCHD 60p (or 50p in PAL countries) recording vs external uncompressed or ProRes HQ 60i. 60p is better than 60i but uncompressed or ProRes HQ is better than AVCHD. I am asking because 60p external recording is not possible on Hyperdeck Shuttle 2 or Samurai (only 60i), it is possible only internally in AVCHD.
This question is not for owners of 60p external recoders:)

I'm also interested in what experiences people have had and the quality comparison. For regular shooting it seems obvious to record external since you have to deliver 60i anyway. When shooting for slow motion the answer is less obvious as there is a trade off between bitrate and progressive.

In situations involving simple surfaces and movement where low bitrates work well, I would guess that internal recording in 60p would be better. In situations involving water and other complex moving textures, I would guess that external recording in 60i would be better. In this case, one needs to use high-quality deinterlacing to recover 60p before further processing.

Imperfections that are not noticeable during regular playback become much more obvious during slow motion playback. For example, the compression errors in the p and b frames from AVCHD source can end up looking quite strange, as if the trees and bushes are swimming underwater. This is especially true when using motion interpolation to further slow the video down. Another way of looking at it is this: If you record at 28mpbs and then view using 1/4 speed slow motion, the bitrate at the time of viewing is only 7mbps.

[Mark Rosenzweig]

Sorry there is no motion, but there is plenty of detail, which also requires a high bitrate:

AVCHD 108060P, 28Mbps:

Atomos Ninja 2 Test Video Comparison 2: AVCHD 28 Mbps 60p from the camcorder on Vimeo

Recorded simultaneously on Ninja 2, Pro Res 422, 145 Mbps:

Atomos Ninja 2 Test Video Comparison 1: Apple Pro Res 422 (145Mbps) 60i Converted to Avid DNxHD 60i (145Mbps) on Vimeo