How good or bad is AVCHD 108060p? - AVS Forum
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post #1 of 2 Old 08-18-2012, 08:21 PM - Thread Starter
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108060p AVCHD video clips are difficult to play and hellish to edit. Video forums are filled with complaints about the sample sizes and the problems they create. Does this video compression scheme and frame rate, given this cost, deliver good video?

Wouldn't it be great if we could take videos at 108060p using AVCHD and simultaneously shoot the same scenes *with the same camera* using a really high-quality, very high bitrate codec that the pros use (and is really easy to edit) to compare?


Well, now we can. And I did.

I borrowed a colleague's Ninja 2 - a video recorder - to see if it produced video that was superior to what my camcorder could produce using its own processor. The camcorder has a clean HDMI signal and uses AVCHD compression, 1080 progressive 60fps, 8 bits per channel with 4:2:0 chroma sampling. I shot with the Ninja and the camcorder simultaneously, the Ninja getting its signal from the uncompressed 108060i put out by the camcorder and using Apple Pro Res 422 (145Mbps, yes, 145 Mbps), which uses 10 bits per channel with 4:2:2 chroma subsampling to compress the uncompressed signal. This is a codec the pros use to edit with. Notice that the bitrate is not only substantially higher, but there is also more information collected on color (chroma) too.

To maximize quality I edited and converted the Apple Pro Res 422 60i clips to Avid DNxHD 60i (145Mbps), which also uses 10 bits per channel with 4:2:2 chroma subsampling, in Sony Vegas Pro. The AVCHD 108060p clips were edited and combined without recompression. The edited videos were then separately uploaded to Vimeo.


The camcorder-produced AVCHD 60p at 28Mbps version is here:

https://vimeo.com/47788836

The Ninja2 Apple/Avid high-bitrate/high sampling version of the same scenes from the uncompressed output is here:

https://vimeo.com/47785992

You can open two windows and run the two videos simultaneously. Or, if you are a member of Vimeo, you can download the originals. The original AVCHD file is 450MBs. The original AVID file is 2.5GBs. They are the same length - high bitrates have a cost.

The scenes have a lot of red flowers and a lot of detail so a challenge for any codec. Sorry about the shaky cam. I was holding the camcorder and Ninja with one hand, but that also challenges the codecs.

Looks like AVCHD 60p does a really nice job, and gives you really small files. See any glaring differences from the Vimeo versions or the originals?
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post #2 of 2 Old 08-21-2012, 07:12 PM - Thread Starter
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Color grading effects on quality: I took the original AVCHD 108060p camcorder video clips and the original Apple Pro Res 422 Ninja 2 video clips, color graded them using the "Warm" preset from Magic Bullet Looks, and converted both to AVCHD 108060i at 22Mbps.

The question is whether the recompression and color grading affects the quality differentially across the two differently compressed videos.

Here is the color-graded video made from the original Apple Res 422 files:

https://vimeo.com/47976353

Here is the color-graded video made from the original 108060p files:

https://vimeo.com/47977029

The uploaded originals (before Vimeo conversion) of both files can be downloaded.
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