Size of CinemaDNG compared to MLV Raw files, please advise

[foundry]

Apologies if this has been answered, i've searched thoroughly and not had any luck so far.

I have a large collection of MLV files shot some years ago (2014 - 2018). Most of the files are 4.29 GB in size. They were shot on 5DIII.

I'm attempting to convert them to CinemaDNG, however the results come out much larger. I'm using MLV App.

I haven't applied any changes, just simply importing to MLV App and exporting using default settings to CinemaDNG.

Using CinemaDNG lossless the result is a file 8.89 GB in size, uncompressed is larger still (around 12GB)

Am i wrong in thinking that uncompressed should be the same size as the original MLV, and lossless, being compressed, should be smaller than original MLV?

The computer i'm using is 2021 M1 Macbook Pro / Max specs.

I'm sure this is a very novice question, but any insight would be much appreciated.

Thank you

[Levas]

Uncompressed DNG will always be bigger.
MLV's are recorded in 14 bit and the conversion to DNG goes in 16 bit (for compatibility reasons I guess )

So conversion from 14 bit MLV to 16 bit uncompressed DNG always comes with increase in filesize.

MLV to lossless DNG should become the same filesize or smaller.
It depends on the settings used with recording. (14 bit normal or 14 bit lossless option) the lossless MLV optiom became available in later magic lantern builds.

So my guess is that most of your MLV's are not lossless compression recorded.
This means you should end up with smaller filesizes if you choose lossless DNG option.
If your MLV's are lossless compressed, you end up with roughly same filesize, since the compression technique is the same.

[foundry]

Thank you so much for your response, and i really appreciate the explanation.

I had a closer look at the files, and yes as you thought they are uncompressed 14 bit.

Unfortunately i did the export again and i had the same result - the 4.29GB file came out at 9.38GB

The only difference i can see is that the MLV seems to have 6079 frames, and the resultant DNG folder seems to contain 6080 frames, each between 1.5mb and 1.7mb.

I'm rather baffled by this! If you have any other clues as to what might be happening or where i'm going wrong, i'd be massively grateful.

Here is a screenshot which might provide a bit more info, the original file settings, and my export settings -

[Walter Schulz]

May I ask if there is an M12-0253.M00 file, too?

EDIT: And M01, M02, M03 and a very small M04.

83 MByte/s x 253 seconds = 21000 MBytes ...

I suppose a facepalm is in order ... ;-)

[foundry]

Thank you, yes there does appear to be those other files too.

But i'm not sure what i'm actually looking at with those - MLV App doesn't seem to allow me to do anything with them, or at least not import them.

Apologies, this is my first time trying to do anything with this footage so i'm completely new to the workflow.

This is the folder with everything from that card -

[Walter Schulz]

Hint: 4.29 GB gives you around 49.35 seconds ...
If MLVapp doesn't handle those files ... why does it show recording duration "4:13"? ;-)

You are not converting 4.29 GB but more than 20!

[Levas]

The numbered files belong to the MLV with the same name.
Your video file is recorded in chunks of 4GB size.
So it starts recording, and around 4GB it creates a new file with M00 extension, if that becomes 4GB in size, another file is created M01 etc.

MLV app automatically connects those numbered files to the MLV file.

[foundry]

Hint: 4.29 GB gives you around 49.35 seconds ...
If MLVapp doesn't handle those files ... why does it show recording duration "4:13"? ;-)

You are not converting 4.29 GB but more than 20!

Ah that makes sense now i think. Thank you very much. The way it was presented visually in MLV App or Finder didn't seem to make that too clear. 

The numbered files belong to the MLV with the same name.
Your video file is recorded in chunks of 4GB size.
So it starts recording, and around 4GB it creates a new file with M00 extension, if that becomes 4GB in size, another file is created M01 etc.

MLV app automatically connects those numbered files to the MLV file.

Thank you. Could i ask, when i import the MLV file, how does MLV app know to connect them if i'm not importing them all together? Is it because they're in the same folder?

[masc]

Could i ask, when i import the MLV file, how does MLV app know to connect them if i'm not importing them all together? Is it because they're in the same folder?

MLVApp automatically scans the entire folder for files with the same name and endings M00, M01,... , when opening the MLV file. So MLVApp knows all those files are just one clip.

[feketeg]

Hey guy!

I'm a newbie with DNG files. When I export from MLV 5k frtp to cDNG lossless it appears in a wierd aspect ratio in Davinci. Please advise how can I recover the original