over/under crank
 

Any news as to the when will the firmware update which includes under/over crank be released?
I know you are busy with the NanoFlash but thought I'll ask as I think this was on the agenda a while ago.

Thanks,
Regards,
Ofer

Dear Ofer,

I could not have said it better.

Yes, we are very busy with the nanoFlash. As such, I do not want to commit to a schedule that we may not meet.

The nanoFlash is going very well, but we want to be able to jump on any issues that may arise. We do not have any issues at this time, but we want to be prepared.

The issue that we just resolved was very subtle. It involved communications between the microprocessor and the FPGA (Field Programmable Gate Array) and it would only fail once every 1.25 million transfers.

So we found it, and now the nanoFlash is more reliable due to our work.

However, this did delay us in implementing new features, such as over and under cranking.

Our next feature is expected to be "Hot Swapping" which will apply to both the Flash XDR and the nanoFlash.

Ofer, as a wildlife guy you'll know that you always want as much slomo speed as you can get (I think most of us are really looking forward to when we can get 120fps as we had on our Arriflexes!), so at the moment you can just set the camera to 720 50P or 60P, into an I frame codec then just conform it in Cinema Tools or whatever, a process that takes just seconds. I think it will be nice to have overcranking in camera so to speak, but if it was me I wouldn't be that fussed at the moment as there is a simple workaround.
Did you try this method yet?
Steve

Hi Steve,
Thank you for your valuable input. No I haven't tried it yet as I only work in Long GOP and never tried I-Farme only. I shoot in slo mo all the time and would love to have this feature in the Flash XDR as promised.
Another factor is that in order to shoot I Frame only at 220 Mb/s I need to replace my Transcend 32GB to the Sandisk Extreme type 4 which is not a cheap exercise.

BTW - has anyone tried the technique Steve suggests with the Flash XDR ?

Thanks,
Ofer

Dear Ofer,

At this time, we do not know if we can implement over and under-cranking in Long-GOP.

Mike thinks not, but it is too early to tell. (I would not bet against Mike.)

Hi Dan, I see. Did you do any experiemnets in getting over crank the way Steve decribes. It does makes sense but I would like to hear if it actually works and whether there is anything I have to consider when going this path.

Thanks,
Ofer

Dear Ofer,

Steve is a true expert. You can rely on what he says.

I agree with Steve, but no, I have not done any experiments.

Hi Dan, I know Steve is an expert (who helped me a lot when I started my journey) and I don't doubt his professionalism just want to hear some input as to the practical side of things (as I know Steve doesn't own the Flash XDR and I assume he didn't actually try it) - preferred bit rate, how will Long GOP and I-Frame only footage cut together and any other factor I have to consider as I am using slow motion very often in my work and would like to get it right.
Another question which I hope isn't too silly - if this procedure gives an identical Slow Motion to what can be achieved in the camera/Flash - why is there a need to include over-crank as a separate feature in the Flash/Nano.


Thanks,
Ofer

Dear Ofer,

Sony Vegas does not support our I-Frame Only modes at this time.

Other NLE's do.

Mixing Long-GOP and I-Frame only in other editors should not be a problem.

Personally, I have not tried it as I use Sony Vegas for editing.

For Long-GOP, my preferred bit-rate is 100 Mbps. This bit-rate goes you added assurance that there will not be any artifacts even if there is an exteme amount of detail or motion in the image.

Faster bit-rates, such as our 140 and 160, are available for your use if desired.

Slo-Motion is only one aspect of over and under cranking. We have choosen to provide frame rates of 1-60 (720p) or 1-30 (1080p). This gives users a wide range of choices, including doing it in post or doing it in a Flash XDR/nanoFlash.

Thanks for the additional information Dan!
If anyone can comment on the few other points I have mentioned:
Will the technique of shooting 720 60p I-Frame only then converting in post to 25 fps - give me identical results to shooting in the slow motion mode in the camera/Flash XDR?
My Transcend cards can only be used up to 140Mb/s - is this high enough quality in I-Frame only compared with Long GOP at 100 Mb/s ?

Thanks,
Ofer

Dear Ofer,

I recommend that you run some simple tests:

1. Record at I-Frame Only at 140 Mbps.

2. Record in Long-GOP at 100 Mbps.

Let us know if you can see any differences.

I feel that Long-GOP at 100 Mbps will be better, but it is up to you if the 140 Mbps I-Frame Only is good enough.

This is really a personal matter.

Thanks Dan,
I guess there is no point in recording Long GOP as it can not be converted to Slo-Mo by the mentioned technique as far as I understand - you can only do that with I-Frame only.
Cheers,
Ofer

Dear Ofer,

Yes, that may be true.

I was recommending that you compare the two modes, with the equipment that you already have.

This will give you knowledge about the quality differences between the two modes.

Then, if the I-Frame Only mode at 140 Mbps meets your quality needs, then you know that you do not need to purchase faster CompactFlash cards.

The benefit (huge) to having overcranking in-camera / in-box is that it's then ready for use with no need for conforming, and that it can be played back AS slomo straight from the box. If you record 720/60P and play it back it'll be normal speed UNTIL you conform it. Also, despite what I said about always wanting as many fps as you can get, it is nice to be able to dial in 32fps or 40 or whatever at times.

Ofer, you CAN do it with GOP codecs, it's just that you have to transcode it to an I Frame (like ProRes) first. This takes quite a while to do (as it needs to work on each frame) and does degrade the quality to some extent.
Best wishes to all.
Steve

Thanks for this valuable information Steve.
I have managed to get the slow motion by using the technique you described and it looks AWESOME !!! Way better than what the EX3 is capable of doing.
However, I believe the Transcend 32GB I am using is not fast enough for the 140Mb/s so I could only get short clips of 5-10 seconds.
Will get a faster card - probably the Sandsik Extreme III 32 GB and will give it a go.

Thanks for all your fantastic input Steve, much appreciated!
Regards,
Ofer Levy Photography

These fast cards are expensive but I think you just have to keep telling yourself that they'll last years and that compared to tape they'll still work out cheap. It's got to be the best idea to put the most bomb-proof cards in the camera when we're working so hard to shoot al this great stuff.
My plan would be to buy some slower cards (Sandisk III) to do 100 mb/s long GOP for 25P stuff and a couple of faster ones (sandisk IV) for 160 or 220 mb/s stuff for slomo.
Steve

Hi all,

Tried to get the slow motion by shooting 720 60p at 160 Mb/s I-Frame only then trying to conform in Cinema Tools to 25 fps as Steve suggested- no luck.
Used 3 different cards: Transcend 32 GB, Sandisk Extreme IV 4GB and Sony 306x 46 MB/s 8GB.

I get the same message in the conform log:
"Skipped - The movie file is not writable .........MOV
Unable to move the file.........Mov"

The clips playback fine but still fail to be conformed.

Any ideas ayone as to what can be the cause for this failure?

Thanks,

Ofer

Dear Ofer,

1. The Transcend 133x 32 GB card is not rated for 160 Mbps.

2. Officially the SanDisk Extreme IV 4 GB card has not been tested.

3. Officially the Sony card has not been tested.

I recommend that you test the 140 Mbps I-Frame Only mode with your Transcend 133x 32 GB card.

Hi Dan, the clips are plying back fine.

Will do the test with the Transcend 32GB at 140Mb/s tomorrow and report to the forum.

Thanks,

Ofer

Ofer, you need to ingest the EX clips as usual, but then they need to be transcoded to an I Frame codec. In FCP go to File, Export, Quicktime Conversion. Then choose Apple Prores HQ, set your destination etc. This will then make a Quicktime at your destination, open this with Cinema Tools and conform.
Do this on a few clips one at a time to begin with to see how they look, but you can also do whole cards by File, Batch Export, and then by Batch Conform in Cinema Tools. The CT bit is quick, but the transcode to ProRes is time-consuming, and worth setting up to run overnight.
Steve

Dear Ofer,

When a chip is inserted, we attempt to identify the Brand/Type/Speed of the chip by reading information built in the controller of the chip.

Some original, or early, Transcend cards do not have this information.

As such, we can not always detect that one is using a Transcend 133x 32 GB card.

Thus, we can not lock out the 160 Mbps modes on these cards, as we do for other cards.

We do not recmmend recording at 160 Mbps onto a Trancend 133x 32 GB card. We do expect this to fail, but it is not an instant failure, it is a failure after a period of time; after our write cache fills up, since the card can not accept our writes as fast as necessary for 160 MBps.

Good news
 

Hi all,

Tried it again today - used the Transcend 32GB, shot 720 60p, I-Frame only at 140Mb/s.

Got the most stunning slow motion!! Way superior to the slow motion I normally get with the EX3.

I actually realized the only thing I had to do differently is to open the clip in FCP first, save it and then open the saved file in Cinema Tools in order to conform to 25fps.

Will get my Sandisk Extreme IV 16 GB in a few days and will try it with 220 Mb/s.

Thank you Dan for the fantastic customer support and a HUGE thank you to all the team in Convergent -Design for this absolutely amazing device. The footage I get using the Flash XDR is definitely in a different league to what the Sony PMW EX3 can natively produce.

Cheers,
Ofer Levy Photography

Dan,

Given the success of I-frame for slow motion, would it be possible to add a 50mbps I-frame setting?

Sometimes longer record times are needed and for many uses 4:2:2 50mbps I-frame or long GOP is fine quality.


BTW, does this I-frame/long GOP difference apply to chromakey?

Dear Tim,

We could run a test, but I am initially concerned about the quality of 50 Mbps I-Frame Only.

Yes, for chroma key, we recommend using 100 Mbps Long-GOP or the high bit-rate I-Frame Only modes.

Hey Dan,

Hope you are well.

Does the Long GOP or I-frame have in impact on chromakey like it does on slow motion outside of bitrates?

Since having every frame helps slow motion I wondered if keying software might benefit from having every frame as well.

About the quality of 4:2:2 50mbps I-frame, I am guessing but I would imaging that it still would look better than 4:2:0 35mbps long GOP.

The usefulness might outweigh the image quality difference.

Dear Tim,

One common misconception is that Long-GOP does not produce every single frame for the Non-Linear Editor. I had this same discussion with an Apple expert at ROSCOR 2009 event in Chicago. He did not believe that Long-GOP produced every single frame.

He thought that if we were filming a hockey match, we could not see the hockey puck, unless it was in an I-Frame in the Long GOP structure.

To prove that it did, we created a test file for him with very fast lateral motion in the frame.

He was amazed at the test results as he did not think Long-GOP could capture each frame of video, but it does.

(His comment was "That is the best video I have ever seen!", then he realized that he had to be politically correct so he said with a big smile "That is among the best video I have ever seen!". It was a great moment.)

Long GOP, when decoded by the Non-Linear Editor, provies every single frame to the NLE.
And since we are full raster and high-bit rate, we provide very high quality images to the NLE.

So, yes, Long-GOP, due to its efficiency is very well suited for chroma keying.


We will need to run tests to see if the quality of 50 Mbps 4:2:2 is acceptable for some uses. Remember that Long-GOP has at least a 2 to 1 or 2.5 to 1 efficiency advantage.

Also, please remember that we are neutral in that we offer both I-Frame Only and Long-GOP, via a menu selection, in our Flash XDR and nanoFlash. It is not as if we are attempting to sell one over the other, we support both.

But, we do know the advantages of each, and that 100 Mbps Long GOP is far better than 100 Mbps I-Frame Only. 100 Mbps Long GOP and 220 Mbps I-Frame Only are probably close.

Thanks for your reply Dan.

I mis-spoke (typed) as I was just trying to separate I-frame from long GOP.

I realize every frame is there, just some have more info than the others. Should have put every "full" frame...

What would cause the slow motion to be better using the I-frame than the long GOP if all of the frames are represented in both?

Is it more how the NLE handles the GOP rather than the footage itself?

Dear Tim,

We are having an internal debate in our company concerning the use of Long-GOP in over and under-cranking.

Until we try Long-GOP with over and under-cranking we will not know if it will work or not, so we are not promising it.

Until then we are expecting to support I-Frame Only for over and under-cranking.

Dan,

I plan on frequently using the nano to record at 720p60 and then conform to 720p24. This is in an application where there is a lot of non-linearly moving water with changing surface textures in the frame, which is usually a tough situation for long-GOP compression like HDV.

With that in mind, would you say that long-GOP is potentially more efficient per bitrate/frame at higher frame rates than low, even when there is a lot of motion involved? So that the potential advantage of long-GOP over I-frame only is even greater at higher frame rates?

My understanding is that long-GOP encodes the difference between I-frames and the intervening frames and then compresses that difference, so if there were more frames per unit time there would be smaller differences between frames, so less information relating to frame/frame difference would need to be compressed into the the overall data stream, and more information relating to single frame quality could be captured. If that is a bit confusing, another way of stating my question would be whether the same action recorded at 720p60 at 100mbps would have significantly higher image quality as judged by looking at each individual frame than 720p30 at 50mbps.

If that is the case, I suppose that might be another reason to consider using long-GOP to capture footage to be used in slow motion, unless there is some difficulty in conforming the long-GOP footage in NLEs to a slower frame rate that I am not aware of.

In practice, I expect to test both long-GOP and I-frame only at the highest bit rates my cards can support and see which gives the best results, but it is interesting to speculate. The other consideration with long-GOP at lower bitrates like HDV is that you see a substantial degradation in overall detail / increase in artifacting as motion increases in the same clip (this is especially apparent when viewed in slow motion), and the contrast in quality between the parts with more and less motion can be quite off-putting. It will be interesting to see how the long-GOP fares in this regard as the bitrate goes up.

Dear Mike,

Please forgive me, but I preparing for a trip.

I will attempt to answer all of your questions as soon as possible.

But for now....

Our experience with extensive testing has shown that 100 Mbps Long GOP (and Full Raster) is very difficult to break.

Extremely high level of detail does not break it.

High levels of motion in the image does not break it.

High levels of camera motion does not break it.


Mr. Richard Wolnowski tested the Flash XDR with his Thomson Viper extensively.

To test the above, he shot the Houston Marathon, he was in the back of a moving pickup truck, with his Viper, with 25,000 runners coming at him. In other words, lots of detail, lots of motion. This is an extreme case.

In watching the video, it was visually perfect. In analyzing the video frame by frame he found two artifacts (as I remember).

We now offer 140 Mbps Long GOP and 160 Mbps Long GOP in addition to our recommended 100 Mbps Long GOP. This was a torture test. In every other torture test our 100 Mbps Long GOP has worked well, just as it did in this torture test.

Our recommendation to use 100 Mbps Long GOP is based a real-world field testing.

We recommend that everyone test the options available to them, with their choice of CompactFlash card speed, and make the decision that best fits their needs.

The beauty of this is you can choose whats best after you have the unit. You do not have to decide before you buy, as one would have to do with a camera. And, you can switch modes/formats to fit your needs on a shot by shot basis.

It's not that it's better, only that if you conform in Cinema Tools it will only do it with I Frame codecs. If you record Long GOP you have to transcode first to an I Frame like ProRes.

Steve