4K RAW Data rates, R5 vs 7Q

G

Gene Sung

Veteran
Hi Mitch or Dan,

I read Philip Bloom's glowing review of the 7Q. His big mark off was that the 4K RAW data rate for the 7Q was about 2.5x greater than the Sony R5 recorder. Why is that? Is there anyway we can shrink down the 7Q 4K RAW data rates to at least match the R5? I have to say after shooting my Macro project, I can see how 4K RAW would be very, very useful for certain projects - VFX and Macro - but dang.... if we could shrink those data rates down to at least R5 levels it would be great.

P. Bloom wrote:
SONY R5

4K 24/25/30p on the AXS system is just over 1 hours for 512GB

4K 50p/ 60p on the AXS system is just over 30 minutes for 512gb

ODYSSEY 7Q

4K 24/25/30p on the 7Q is 24 minutes per 512GB card.

4k 50p/60p on the 7Q is 12 minutes per 512GB.
 
That sounds about right. I actually shot a project in hyper-real looking 4K 60p w/audio and got about the same amount of recording time as Bloom stated with the R5. I believe it's because the R5 records the supposedly lossless form of the compressed raw which is kept in Sony raw mxf format. I think the compression is roughly 2.5-3x.

It sounds to me like the O7Q can recognize and decompress the FS700's flavor of raw coming out the 3G SDI, but then converts to dng which is truly uncompressed at that point and hence 2.5x bigger data.
 
The comment is that, I beleive, C-D is already working on a compressed 4k solution for the O7Q.
 
cuervo said:
The comment is that, I beleive, C-D is already working on a compressed 4k solution for the O7Q.
Click to expand...

Do you mean a 4K RAW compressed? Or a 4K Pro-Res solution? Both would be great. It would be nice to get the RAW file sizes down though.

It's kind of like before 4K RAW, I didn't really think I needed it, but after getting a taste of it I can see how it would be really useful for somethings.
 
This may have been shared or discussed here before and I apologize if this is a dupe from another thread, but I understand that the CinemaDNG format supports lossless compression. This is what's currently implemented in the Blackmagic Pocket Cinema Camera. I am only just beginning to familiarize myself with my Odyssey 7Q, but it looks like the current CinemaDNG flavor is uncompressed hence the massive file sizes. If support for lossless compression could be added to the 7Q via a future firmware update and be a user toggle-able option this would help massively - potentially halving the file size of a given raw frame with no drop in quality or data integrity (lossless compression effectively working like a zip file).

Losslessly compressed CinemaDNG raw, plus the ProRes compressed option for 4k would be high on my wish list.

Here is a good post with more details:
http://www.redsharknews.com/technol...exactly-is-lossless-compressed-cinema-dng-raw

Mitch -I apologize if I have my information wrong regarding the 7Q...
 
morgan_moore said:
Me musing.. compress in the warm http://www.sammorganmoore.com/backlot/data-loads-and-raw-delete-your-rushes
Click to expand...

I partly agree with what you wrote, but there are times when 4K RAW is perfectly feasible. For example, one of the studios I work for shot a 10 second, VFX heavy show open on the FS700. It was a 1 day shoot, everything was carefully controlled and I think they ended up with about 30 minutes of total footage for a 15 second spot. They would have killed for 4K RAW if it was available then.

Now 30 minutes of 4K RAW for a TV production studio is very doable and on the easy side of storage since they have massive servers. Even for myself, 30 minutes of RAW is nothing. But yeah, for projects that are footage intensive, 4K RAW is obviously not ideal.
 
Of course 4k is doable for a 5min spot, very planned, go any longer and there may be issues, obviously for a movie again it is possilbe.. it is the mid ground

S
 
You can zip or rar the files on your computer and save about 40% on diskspace, so compressing CineDNG losslessly on the fly should be possible.

But : 1.Does the OD7Q has the processing power to do it ? 2.Working with compressed files should also take more processing power on the computer side, shouldn't it ?
 
The original RAW data out of the 7Q is compressed by about 3x. The R5 records this, but Sony has not allowed us to record this so we decompressed them and then convert them to .cGND files which are then recorded uncompressed. We are in talks with Sony to allow us to record the original compressed RAW.

Recompressing into a different file format such as cDNG compressed is a bad idea. If something starts out compressed, is decompressed and then compressed again a different way, these compressions will never match and can cause concatenation artifacting. You can learn more in my article here:

http://www.convergent-design.com/Su.../On-Compression-Codecs-and-Concatenation.aspx
 
Last edited:
It's my understanding that there is a lossless compression possible with cDNG files and there is a visually lossless Adobe DNG convertor out there but as Mitch cautions, compounding compression is never a good idea and that's what we'd be doing (the source is compressed, even if the DNGs aren't)

Being able to record the source data would be ideal, we could use the existing Sony tools then, so best of luck with those conversations! Big +1 there!

cheers
Paul
 
keep my fingers crossed for successful conversation with Sony too!

Getting half size DNG files by the Adobe DNG converter is tempting
especially as I did not see any artifacts up to now.
 
Mitch Gross said:
The original RAW data out of the 7Q is compressed by about 3x. The R5 records this, but Sony has not allowed us to record this so we decompressed them and then convert them to .cGND files which are then recorded uncompressed. We are in talks with Sony to allow us to record the original compressed RAW.

Recompressing into a different file format such as cDNG compressed is a bad idea. If something start out compressed, is decompressed and then compressed again a different way, these compressions will never match and can cause concatenation artifacting. You carn more at my article here:

http://www.convergent-design.com/Su.../On-Compression-Codecs-and-Concatenation.aspx
Click to expand...

Yes, this would be amazing. Please convince Sony.
 
Mitch Gross said:
The original RAW data out of the 7Q is compressed by about 3x. The R5 records this, but Sony has not allowed us to record this so we decompressed them and then convert them to .cGND files which are then recorded uncompressed. We are in talks with Sony to allow us to record the original compressed RAW.

Recompressing into a different file format such as cDNG compressed is a bad idea. If something start out compressed, is decompressed and then compressed again a different way, these compressions will never match and can cause concatenation artifacting. You carn more at my article here:

http://www.convergent-design.com/Su.../On-Compression-Codecs-and-Concatenation.aspx
Click to expand...

That would be ideal - Sony Raw viewer is an excellent tool - we're really hobbled having to use CDNG & Resolve. Is there anything we can do to help convince Sony? Another thread on their customer forum?
 
A wavelet raw compession like RED does it would be ideal - why aren't any other companies doing that? untill 5:1 or even 8:1 it's virtually lossless.
 
Before we get ahead of ourselves, in the alternative universe, the one where the IXR and AXR are good ideas - isn't it the case that the IXR decompresses the RAW from the FS700 and the AXR just records normal Sony RAW as if it was from the F5/F55?

Is normal Sony RAW even compressed? - i don't have any handy, just some MXF files. It looks like they are compressed (a single frame from the MXF for the F55 appears to be 5MB ish)

What we're talking about here is the very specific output from the 700 which *is* compressed to get it over the 3GSDI, compared to the resulting Sony RAW files from the AXR which may be compressed differently?

I don't know the answer to that.

cheers
Paul
 
They are all compressed the same. The compression happens in the camera, not the recorder.

No, please don't pressure Sony on this point. We are not at such a stage.
 
Mitch Gross said:
They are all compressed the same. The compression happens in the camera, not the recorder.

No, please don't pressure Sony on this point. We are not at such a stage.
Click to expand...

Sorry to be pedantic: Do you mean that even on the F5 and 55 that the RAW is compressed in camera?

thanks
Paul
 
Sounds like that's the case PAul. Compression happens in camera to the real RAW data. IOW, the signal provided at the SDI port has already been compressed to some degree.
 
You must log in or register to reply here.
Back
Top