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-   -   Nano 220Mb/s I-Frame question (https://www.dvinfo.net/forum/convergent-design-odyssey/488636-nano-220mb-s-i-frame-question.html)

Rafael Amador December 16th, 2010 07:34 PM

Quote:

Originally Posted by Mark Job (Post 1599182)
…..There is. In Long GOP only. Anything above 50 Mbps is under performing IMHO. The Sony XDCAM HD 4:2:2 hardware encoder wasn't designed with higher data rates in mind in Long GOP, and subjective personal testing on my part has revealed to me (*only in Long GOP*), that if you want higher quality more like uncompressed, then you need to use I-Frame (Intra) @ 220 or 280 Mbps to get it.
….You can't.
…Please follow the link in this forum and go watch my latest commercial production and see this for yourself. HDV & Long GOP do look the same. However, I did no shooting in Long GOP 100 Mbps, so I can't show you this yet.
….Academic. Will only serve to frustrate as you learn the limitations of 8 bit MPEG - 2. Superior results are possible with recording in Quicktime Movie, or 10 bit uncompressed. XDR is capable of 10 bit uncompressed. Not turned on yet.

Mark,
The SONYS MPEG-2 files are standard MPEG-2 files and can implement the options set by the standard.
A different issue is that the processor is able to implement those options and how well does the job.

You are very categoric about that there is nothing to fix on the NANO/codec.
Give me reasons.

I saw your clip just few minutes after you uploaded.
I was about to post you.
For me the picture doesn't look the same at all.
However if I didn't post you is because I think is a waist of time trying to judge on a Vimeo clip the efficiency of the SONY LGOPs MPEG-2.

About the MPEG-2 (10b MPEG-2 can't exist) vs 10b unc, can't bring frustration to me because I learnt my lesson before buying the NANO.
I new what I needed, and know what I can expect from High data-rate MPEG-2.
Don't blame the format.
If the SONY processor is the problem, that's a different issue.
rafael.

Gints Klimanis December 16th, 2010 08:15 PM

100 Mbps LongGOP offers an improvement in areas with motion and some areas with detail over 35 Mbps SxS. Areas with a lot of motion show the ghost-blocks and macro-blocks for lower bitrates.

Garrett Low December 16th, 2010 10:37 PM

Hi Simon,

I'm in the early stages of staring a documentary that currently has not received outside funding (I'm working on that). I"m planning on shooting most of the footage using 220Mbps I-Frame. For color correction purposes I don't see a difference between 100Mbps long GOP but to my eye there is a very noticeable difference in any motion and I-frame only at high enough bitrates just looks cleaner to me.

I'm hoping to be able to have our documentary go out to various distribution channels so I'm planning on starting with the highest quality master footage as possible.

From my observations there is a very noticeable difference between 50Mbps and 100Mps Long GOP.

However, if you are only going to go out to Vimeo, 100Mps Long GOP would be more than enough.

Just my opinion.

-Garrett

Gints Klimanis December 17th, 2010 12:06 PM

Vimeo Plus membership includes a file download option, so higher bitrate distribution to a large audience is easy.

Simon Wood December 18th, 2010 12:28 PM

I guess 100mbs Long GOP will be my 'sweet spot' - seems to tick all the boxes! Thanks for the suggestions y'all.


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