Background for those who may not know,..
"Raw Video", in most form, is a series of Lossless Compressed DNG files, with one file per frame of video.
Lossless Compression, is where the DNG file is compressed, much the same way as a PC file is compressed in a Zip or ARJ archive.
It should not be confused with 'Lossy Compression - which is where the footage is fed in to a CoDec (Mjpeg or h.264 in Pentax cameras) and the compression is applied within the video frame (Intraframe, Mjpeg), or over a "Group of Pictures" (GoP - Mpeg2, LongGoP, Mpeg4/h.264) before the video format file is written.
In those cameras that write Raw video as CineDNG files, the sensor data is never processed with filters for sharpness, and if you choose the right camera, there's no messing about with the colours - Ideally, the files are the same as if you'd taken 24 or more stills in a second writing to DNG.
The advantage, is the same as using Raw DNG files in Stills - you can apply a lot more colour correction in Post Production.
Those cameras that shoot Raw, use the SDI ports and cables, to send that data to external recorders.
Serial Digital Interface, is a stream of digital data, at a high enough data bandwidth, to transmit all of the uncompressed cameras.
SDI isn't used in 'Consumer' based video capable devices as it's an expensive interface to make, due to needing to sustain data rates from 1.5 Gigabits through to 12Gigabits depending on the device used.
For SDI to be fitted to a DSLR or MILC, the raw sensor data would need to be routed directly to SDI encoders.
It's a guts-open and solder in new bits job, and only if you can find a module that will accept the data from the sensor.
As much as I'd love to see this happen, it's not cost effective on any consumer product.
The least expensive camera with SDI is the BMD Cine Camera, which launched at a price of $3000US.
The vast majority of Digital Cinema cameras fitted with SDI, are $5000US and above.
Now, as for 'Raw Video', If you have a high enough speed memory device, and the right coding in the firmware, you can write the DNG files directly to the recording medium.
BMD's 'Pocket Cinema Camera' writes CineDNG Raw lossless compressed files to an SD-XC card.
It requires a card capable of 90+ Megabits per second, such as the Sandisk Extreme Pro class cards, and a processor capable of performing the lossless compression.
Shifting the data, Yes, I expect the SD-XC controller in the Pentax cameras is capable of that.
Performing the lossless compression, that would be the hard part. However, the Magic Lantern crew have been able to get CineDNG Raw out of cameras that are much older then most of the current Pentax range.
What would be needed for Raw Video out of the K-3, K-1 or KP, would be for Ricoh to give the Pentax-Hack crew un-encrypted access to the firmware.
It's very doubtful that would ever happen, even with security and privacy agreements and contracts.
With access to the firmware, and a really talented coding team, it would be, wiser, IMHO, to use the ethernet function of the HDMI protocol to send the raw sensor data to a custom built external device that can convert it to CineDNG Raw in a format already supported, such as Canon, Panasonic's, or Sony's, and pass that to an external recorder.
Last edited by PiDicus Rex; 07-06-2017 at 01:45 AM.
Originally posted by stevebrot 
Post #7 by PiDicus Rex
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