Variable bitrates?

[Jack Kelly]

Hi folks,

Just a quick question. Forgive me if this has been answered before; I did a quick search but didn't find any info.

Will the user be able to set different bitrates for the REDCODE / RGB encoding on the camera? For example, the current (draft) specs state that the S35 Scarlet will record using REDCODE 80. Does that mean that the S35 Scarlet will ONLY record at 80 MBytes/sec? Or will users be able to select different bitrates? (For example, you might want the highest possible quality for a drama shoot but you might want a lower bitrate for a doc where you're shooting many hours).

 

[Stuart English]

Image Quality / Run Time on Media

Image Quality / Run Time on Media

The new cameras will offer a choice, just as the RED ONE does.

 

[Jack Kelly]

Great, thanks for the very quick reply!

 

[Lee Saxon]

Also they've stated that the numbers in the new redcode settings are not literally the bitrates, they're just a relative metric for comparing quality between cameras, so REDCODE 80 probably isn't 80 MB/s

 

[Gavin Greenwalt]

But it's also not a relative metric for comparing compression quality since it also denotes a higher resolution.

The new metric is just random and confusing. It both denotes an improvement in quality and an increase in size. But not necessarily either over current redcode.

 

[Lee Saxon]

But it's also not a relative metric for comparing compression quality since it also denotes a higher resolution

In comparison to the current RedOne that's true. For all we know the Epic's RC225 is analogous to the current RC36 and the Scarlet's RC80 is much lower!

 

[Stuart English]

Data Rates

Data Rates

For all we know the Epic's RC225 is analogous to the current RC36 and the Scarlet's RC80 is much lower!

It isn't though... and bear in mind that the efficiency of RED compression technology is also improving... :thumbup:

 

[Hrvoje Simic]

I'm interested if we will be able to shoot scaled at max. bitrate, rerouting compression engine after scaling engine (guesswork) - if that makes sense in terms of chroma/luma information per pixel (compared to full res at same bitrate scaled in computer).

 

[Jack Kelly]

I'm interested if we will be able to shoot scaled at max. bitrate, rerouting compression engine after scaling engine (guesswork) - if that makes sense in terms of chroma/luma information per pixel (compared to full res at same bitrate scaled in computer).

I could be wrong but I think that as soon as you scale the image in camera, the camera has to use REDCODE RGB rather than REDCODE RAW (or whatever the exact names are). So, in other words, you're not comparing apples to apples: as soon as you downsample the image in the camera, you have to use a different compressor. I'm sure RED will ensure that the REDCODE RGB records at a sufficiently high bitrate to make the compression artefacts virtually non-existent.

As I understand it, you have to demosaic the RAW signal before you can scale the image.

So, in other words, the two "pathways" in the camera are:

1) Sensor's raw output -> REDCODE RAW compression

or

2) Sensor's raw output -> demosaic -> down-res -> REDCODE RGB compression

if that makes sense.

 

[Lee Saxon]

It isn't though... and bear in mind that the efficiency of RED compression technology is also improving... :thumbup:

Good to hear, man! Thanks.