Extract pixel info from quicktime

[john-hu]

Bit of an odd one but hopefully someone has a clue how I can do this. I want to be able to extract pixel data from DNXHD encoded Quicktime.

The goal is to try and find out if the video data was encoded full range or legal range. Basically I need to get the RGB value of pixels to see if black reaches close to 0 at any point, indicating full range, or is significantly higher, indicating legal range. Does anyone know of any way to extract this kind of data?

Thanks in advance

[poisondeathray]

One way is to it up in a NLE and look at the waveform monitor

The results you get may vary: some decoders might expand to pc range 0-255, some might keep 16-255.

Another method might be able to use avisynth (e.g. qtinput() and videoscope() )

There might also gamma differences IIRC, if it was done on a mac vs pc (1.8 vs. 2.2) using QT MOV

[john-hu]

Thanks for the suggestion but to explain the issue in a little more depth...

We have a pipeline in our film department part of which is receiving a client quicktime which we in turn use to reference grade dailies to then be sent back to the client for approval. The material 'should' always come in from the client legal range, but because the rest of the pipeline comprises of various legal to full range and back again conversions, its imperative that the material coming in is checked to be actually legal or the rest of the work flow will be compromised. The easiest way to do this would be to run the incoming quicktimes through a script which will quickly and easily tell you if the material is full range or legal range. Manually checking each quicktime on a WFM is unfortunately not practical...

I will have a look at avisynth as a solution although it does not appear to be in our standard workstation build unfortunately.

[poisondeathray]

Well the avisynth alternative I suggested basically displays a waveform monitor, and you would still have to examine it manually

I suspect you are looking for some automated solution which notifies you which videos are "legal" and which are not

I don't know of any... sorry

[john-hu]

Ok, well it may be a bit of a tall order tbh, I cant seem to track down a solution either at the moment. I'll carry on looking but the 'solution' may be just to educate those dealing with the incoming material and make sure they know what to look for :)