.RED 4k Delivery codec. 4096x2160 in a 2.5MegaByte/s stream.

[demistate]

I want to know how they are achieving this.

http://www.red.com/store/products/redray-player?utm_source=red.com&utm_medium=homepage&eBslide&utm_campaign=REDRAY_Launch


RESOLUTION: Up to 4096 × 2160 pixels, 2D or 3D
DIMENSIONS: 316 × 61mm x 260 mm ( 12.4 × 2.4 × 10.2″ )
WEIGHT: 5.9 Lbs
MATERIAL: Aluminium
OPERATING TEMPS: Zero to 40 C
STORAGE TEMPS: Minus 5 to 60C

BIT-DEPTH (COLOR): YCbCr 12-bit 4:2:2 or RGB 8-bit 4:4:4
COLORIMETRY: ITU-R BT.709
VIDEO FILE FORMAT: .RED (4K), .MP4 (1080p, 720p)
PLAYBACK FRAME RATES: 24, 25, 30, 48, 50, 60 fps
GENLOCK: RS170A Tri-level Sync

PROGRAM OUTPUT: 4K DCI, UltraHD, 1080p, 720p
MONITOR OUTPUT: 1080p, 720p
OUTPUT CONNECTORS : 4 x HDMI 1.4 (Program), 2 x HDMI 1.3 (Monitor and Audio)

DIGITAL MEDIA: Internet download, SDCard or USB-2 flash media

AUDIO FILE FORMAT: .RED (up to 7.1 Ch) .MP4 (Stereo)
AUDIO OUTPUT: Up to 7.1 channel LPCM, 24-bit 48Khz



According to one of the engineers on the Reduser forums the internal format is actually greater than 4:2:2 12-bit YUV format, however that's the best HDMI can output at the moment. 16-BPC TIFF files are accepted as a valid input, so it's possible they are storing the data in 16-BPC RGB format and converting on the fly. They won't reveal how the format is stored internally.

They also mentioned that REC.709 is the best that HDMI offers right now, therefore the internal colorspace of the file can be better.

I just want to know how they are pulling off this magic. If you were to compress a simliar master with x264 could you even have a 10-BPC encode that was visually transparent with the source material at 2.5MB/s? Keep in mind these are designed to be shown on huge movie screens in dark rooms where you could see every compression artifact if you looked.

They cited that this was one of their most demanding encodes at 4K and it looked visually lossless at their 20MegaBits/s datarate:
http://red.cachefly.net/Tattoo2K.mp4 (This is a 2K version h.264 encode at around 16MegaBits/s, 8-BPC, 4:2:0)

[kolak]

It's just AVC codec. Magic comes from the source. RED files are very clean and encode very well. I done many encodes for HD with 17Mbit which looked very transparent to the source. In case of film camera based sources you need 1.5 or sometimes even 2x more bitrate.
There is nothing special in this source- looks good, but only because master is very good, so at the end they don't to anything special. It also looks like they use ordered ditheirng to avoid banding.

[demistate]

What I'm asking is a 20% increase in bandwith going to cover 12+ BPC precision + 4:4:4 + 4x the frame size? I feel skeptical even if their RED codec is just highly optimized AVC.

[kolak]

Higher precision video encodes better, so this will actually help. Even so 4K at 20Mbits- hmmm, there are many descriptions of transparency, depending what your quality demands are.

This file which you posted looks fine, but this is not some reference level. This is not a file, which you want to use as a source for huge screen in cinema with reputation, but for smaller one it may work. There are many smaller cinemas which use Blu-ray discs as a source for their projection :) 100Mbit long GOP AVC may be very good. 4K DCP masters are nothing more than 200Mbit or so JPEG2000 files (and this is I frame only). 100Mbit long GOP AVC will be not far from it, but not 20Mbit.

For me it is a joke saying by RED that their 20Mbit AVC 4K encode is transparent- they may abandon their REDCODE codec inside their cameras if they achieved transparency with AVC at 20Mbits :)
Don't expect much, take it as PR bla, bla bla :)
REDRAY sounded amazing when it was announced long time ago, now it's nothing special. You can build REDRAY by yourself and it may end up being even better :)
Still not released?