Ron,

I use 220mb I-frame with my XLH1S/Nano combo. Footage always comes out great!

…Hi Ron:
I use Long GOP 50 Mbps and HDV for my paying jobs, and I-Frame 220 & 280 Mbps for my personal work with my XL H1.

Great.
For me if the NANO pictures at 220/280 Mbps I-frame looks great, MEANS NOTHING.
That's what is expected

What I want is that the 100Mbps and 140 Mbps LGOP look AS GOOD as the 220/280 I-Frame.
This is what the NANO MPEG-2 supposed to do; isn't it?.

So:
- If people are not using 100/140Mbps because there is not a clear advantage over 50Mbps: There is something WRONG.
- If we are not getting similar quality on 100/140Mbps LGOP and 220/280Mbps I-frame: There is something WRONG.

I haven't bought the nano to record at 35/50Mbps (SONY does that).
I haven't bought the NANO to record at 220/280 Mbps. That data-rate is CRAZY.

The NANO should shine at 100/140 Mbps L-GOPs. There is where should show the advantages relating Quality/File Size. There you should get the same quality than I-Frame 220/280 Mbps, but half file size.
Again, if this doesn't happens: There is something very WRONG because all that we heard about L-GOPs efficiency is FALSE.

rafael

PS:We are saying many no senses about efficency/data-rate.
FACT: 140/180Mbps L-GOPs and 220/280Mbps I-Frame, should look VIRTUALLY UNCOMPRESED.

To compare the efficiency, we have to start from those data-rates down.
We can not take like reference the EX 4.2.0/35Mbps files, and see how rising the data-rate the picture improves (or not).
We have to start by the top setting and see how the picture degrades when reducing data-rate.

Thanks Michael,

I went out this morning to try the new settings on some Bewick's Swans (Whistling is the Yank sub-species) which I found yesterday, but as is invariably the case the birds had flown. I'll have another go tomorrow,

Ron

Hi Michael,

I have the same setup and also do some wildlife shooting. I normally use 100mbps Long GOP setting with a prebuffer. I really appreciate the pre-buffer because often an action starts more quickly than I can predict it.

This morning I went to try the suggestions in this thread, setting my nano to I frame and 280mbps. The nanoflash reduced my speed to 140mbps. I tried again at 220mbps and again the nanoflash reduced the bitrate to 140mbps. I then removed the prebuffer setting and the nanoflash allowed the two faster bitrates (220 and 280) with no difficulties.

Something to be aware of.

Alan

Thanks for the info Alan. I use my XL/Nano mostly for tv broadcast or narrative work, where prebuffer is not a requirement for me, so I never use it. Its good to know this.

RE: 100 and 140mb L-GOP

I would think that since Sony has never had a product that utilized this codec at those bitrates, that they didn't optimize it at those bitrates. They do with 50mb, and thats why it looks the way it does.

Dear Friends,

We perform quite a lot of testing with our Flash XDR's and nanoFlashes.

And, of course, we welcome the opinions of others.

Is anyone really saying that 100 Mbps is worse than 50 Mbps?

If so, then that conculusion is not borne out by objective testing using very sophisticated systems designed to test video quality objectively.

50 Mbps 4:2:2 and 35 Mbps 4:2:0 have approximately the same compression ratio, when one considers the extra data present in the 4:2:2 video stream.

We fully support the conclusion that 50 Mbps 4:2:2 is Broadcast Quality.

I also state that 100 Mbps 4:2:2 gives one more assuance that there will not be problems in the video stream when there is an excessive amount of detail and an excessive amount of motion.

Sony spent untold millions of dollars developing the codec module. Far more than what would be justified to use it in only two cameras.

Also there are untold numbers of our customers using 100 Mbps Long-GOP with great success.

Since the nanoFlash and Flash XDR's are very versatile devices, you may run your own tests, put it through you own post process, and make your own decision.

Dear Rafael,

You don't even have an idea how much better your above post has made me feel. So far, I've felt very lonely in my opinions, and frankly have given up pursuing the matter further as people (not just CD) started treated me like a paranoiac :)

Unfortunately, I don't have the hardware required to run the testing you proposed in your email to Dan and myself. Therefore, I'd be very grateful if you run the tests yourself, and publish the result in the original thread of mine (the one that "refuses to die"") :)).

Piotr

Dear Dan,
I stated that I shoot a 99% of my work at 100Mbps.
That's the standard quality I want from my NANO, and I'm very happy with it.
I don't gonna waist my time testing 50Mbps, because I don't need any test to know what a 50% cut in data-rate can do to my picture.
I may spend time in making tests with 140/180Mbps to see if those extra 40/80Mbps improves my "standard 100Mbps" shooting.
I just wanted people to be a bit more critic or experimental.
I wouldn't be happy If I would be limiting my NANO to shoot 50MbpsLGOPs and 220Mbps IF.

We all agree that most of the tests brought here so far, do not stand a close examination.
They have been done with a variety of cameras, presets, subjects,.. Most can not be reproduced.
A proper test needs to be repeatable as many times as needed.

As I posted you I'm preparing a simple test that we can share and try, whatever our system or NLE.
The process will be very simple:
- Generate a high quality clip (with signals able to test the behave on detail, fast moving picture and noise)
- Play that clip through a reliable video-card with SDI Out.
- Record the SDI to the NANO at different data-rates/structures.
Then, comparing the signal before/after NANO would be easy done in anyone computer.
I'm far from my place, so I won't be able to prepare this till the end of January.
Best,
rafael

Long GOP 50 Mbps is a setting which has been optimized
 

…Hi Rafael: Wrong ! Sony has most likely *Optimized* the Long GOP 50 Mbps setting, because this is what gets recorded to disk in the XDCAM HD cameras, so I think this makes Long GOP 50 Mbps the real sweet spot in the Long GOP family of settings. Just because you double a codec's data rate does not automatically imply it will be superior. I think my XL H1's 25 Mbps HDV tapes look *Equal* to Long GOP 50 Mbps (Only in daylight shooting), but the low data rate codec suddenly reveals itself in lower light and indoor shooting. The Long GOP family of settings in my XDR are far superior in low light interior shooting conditions, plus the fuller HD raster and extra color space reveal themselves in lower light interior shooting as far superior versus HDV. You have four major factors working for you with the Nano/XDR which make things look better.

1. Superior Color Space: 4:2:2 vs 4:2:0
2. Superior HD Raster Size: 1920 x 1080 vs 1440 x 1080 in some cameras.
3. Superior Processing Sony Codec Hardware Chip: Settable to higher data rates then in camera recorders.
4. Ultra High I-Frame data rate recording: 280 Mbps which is the *Only* setting where the claim can truly be made that it looks close to uncompressed recording.

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