Dear Rafael,

Thank you. I thought you were very happy with our 100 Mbps Long-GOP mode.

However, due to language differences, I thought that some were interpretting your posts otherwise.

I am traveling this week and can not perform the tests that you suggested.

I agree completely with the need for detailed tests.

Mark,
The process is not like that.
We do not start with a poor data-rate and then add more data rate to see what happens.
We start with an 8/10b Uncompressed signal.
I do not expect 100MBps to have DOUBLE quality than 50Mbps,
Neither I expect 50Mbps to be HALF quality than 100Mbps
But I expect 100Mbps to show the higher data rate when Color Grading, masking, etc.
Is very possible that, as you suggest, SONY has optimized the 50Mbps codec, or better have optimized the MPEG-2 Processor for 50Mbps (with XDCAM, SONY targeted his old, storage hungry, Betacam clients),
This is what we are trying to find out; if there is some "under-performance" on situations where the codec should shine more. If there is such under-performance, we have to try to fix it.
I wouldn't feel happy if I would find than my NANO at 100mbps, at 50Mbps and my HDV tapes look basically the same.
So lets make some serious tests, and lets eliminate our cameras from the equation.
rafael

Let's See What We Can See ?
 

…..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.

This thread is losing me.

I'd like to interject with some basic questions:

I'm about to start filming a documentary, and I'd like to be able to do some proper color correction on it afterwards (something that was not really feasible with HDV). But I'll be shooting tape as backup.

There is no clear path in terms of where the documentary will eventually end up - its a good story but self funded in my spare time. Most likely the finished piece will go straight to Vimeo - but I'd like to keep my options open in which case 50mbs Long GOP should be acceptable for broadcast in that unlikely eventuality.

I was originally planning to shoot on 50mbs Long GOP. But then decided I may as well keep the project 'future-proofed' in which case I thought I ought to shoot at 100mbs Long GOP.

Is the consensus that there would be no benefit to shooting 100mbs over 50mbs?

I dont want to go too big either, because I dont think my computer & storage could handle 280 I frame.

What to do...

Record it at 100Mb Long GOP.

There is an appreciable difference (for the better) versus 50Mb.

Billy

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.

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.

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

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

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