Welcome to our community

Be a part of something great, join today!

Log in
  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

1080 timeline 4k 25p smooth, 3k 48 not smooth.

Joel Arvidsson

Joel Arvidsson

Well-known member
Joined
Nov 3, 2008
Messages
3,044
Reaction score
6
Points
38
Age
46
Location
Sweden
I wonder why 4k in a 1080 timeline is smooth with full debayer (scale to fit) but 3k 48p in the same timeline stutter. I have to go down to half debayer to get it smooth. Is it the 48 to 25 conversion that is so slow? Should be easier to play back the 3k 48fps at 25p than the 4k you would think.

Im using the decklink 4k extreme for io if that makes any difference.

Red, please give us 50fps at 3k. 48 is so anoying.
 
Joel Arvidsson said:
I wonder why 4k in a 1080 timeline is smooth with full debayer (scale to fit) but 3k 48p in the same timeline stutter. I have to go down to half debayer to get it smooth. Is it the 48 to 25 conversion that is so slow? Should be easier to play back the 3k 48fps at 25p than the 4k you would think.

Im using the decklink 4k extreme for io if that makes any difference.

Red, please give us 50fps at 3k. 48 is so anoying.
Click to expand...

Its not optimal but its translates pretty good when rendered. If i go 1/2 debayer it plays back allright.
Any chance to download a 3k 50p clip from an epic would be graet for trouble shooting. Will do further testing with 2k 50p but i will never use that in production. 3k is my sweetspot.
 
Julien Deka said:
maybe you can right click in the bin on your 3K clips and choose "reinterpret footage" to change the base frame rate to 25. I assume it is right now 23.976 or 24 but I might be wrong.
Click to expand...



With the old RED1 proxies, you could retime those with cinematools.

I guess going to 50 and then down to 25 would make a smoother result.
 
The 3k is shot with a projekt base of 25p so i think premiere should read it correct. But i will have a look at it. Is rhe cinemaconverson only for mac?

Since I dont use the audio it is not much of a converssion. It is just to playback 25fps until the frames is all played.
 
Julien Deka said:
maybe you can right click in the bin on your 3K clips and choose "reinterpret footage" to change the base frame rate to 25. I assume it is right now 23.976 or 24 but I might be wrong.
Click to expand...

The base is interpreted as 25 in premiere so far so good.
 
I tested to make a 24p and a 29.976 sequence and inport the clips to. Both is lagging on playback from timeline.
 
When 4k playsback 25fps smooth and 3k at 25fps stutter. Something smell fishy!
 
I did call adobe today and it took 1.5hour just to get my email registered for the ticket. Than I had to hang up to fetch my kid...
 
I got a intresting theory from a guy in another forum.


I think I might know why. Redraw is a wavelet codec, which means it can build up the file to various smaller resolutions rather then doing the full res.

My guess is that since you're editing in a 1080p timeline, the 4k is only being decoded to 2k and then scaled down to 1080p

The 3K however, can't be decoded to 1.5k since thats less then 1920x1080 so it has to be decoded to full 3K and then scaled down to 1080p

So Premiere has to do more work with the 3K then the 4K

Thats my guess.



Is this correct. Can Red confirm? Does anybody without the rocket have smooth playback with premiere and 3k files at full debayer using an decklink card?
 
Hey Joel,

I'm reading a few conflicting bits of information in your post, so just wondering if I can get you to clarify some things for me?

You say that you are able to playback 4k 25p with a full debayer. Is this without a RedRocket? If so, I'm guessing you must have an incredibly beefy system?

Are you trying to run the 3K 48fps footage back at 25fps or at 48fps? Sounds like you are trying to run it back at 25fps based on your earlier posts (especially since you set the timebase to 25). Taking that assumption on board (that you are trying to run it back at 25fps), it does seem very strange indeed when you are able to playback 4K with a full debayer in real time.

Are you sure you are playing back 4K full debayer, no RedRocket and in realtime? Definitely sounds like something strange is going on if so and you can't run 3k @25fps.

Just for comparison, here are the pixel counts for full debayered images:

4k @ 25p
221,184,000 pixels per second

3k @ 48fps
238,878,720 pixels per second

3k @ 25ps
124,416,000 pixels per second
 
Brad Allen said:
Hey Joel,

I'm reading a few conflicting bits of information in your post, so just wondering if I can get you to clarify some things for me?

You say that you are able to playback 4k 25p with a full debayer. Is this without a RedRocket? If so, I'm guessing you must have an incredibly beefy system?

Are you trying to run the 3K 48fps footage back at 25fps or at 48fps? Sounds like you are trying to run it back at 25fps based on your earlier posts (especially since you set the timebase to 25). Taking that assumption on board (that you are trying to run it back at 25fps), it does seem very strange indeed when you are able to playback 4K with a full debayer in real time.

Are you sure you are playing back 4K full debayer, no RedRocket and in realtime? Definitely sounds like something strange is going on if so and you can't run 3k @25fps.

Just for comparison, here are the pixel counts for full debayered images:

4k @ 25p
221,184,000 pixels per second

3k @ 48fps
238,878,720 pixels per second

3k @ 25ps
124,416,000 pixels per second
Click to expand...

Hi Brad,

Yes I playback 4k smooth with fulldebayer. But i have checked the "scale to fit" option. So premiere throws away alot of info. But the decklink output looks good much more sharp en nice than working in scaled down with motiontab and 1/2 debayer.
Yes I captured 3k 48fps as 25p. Premiere is than playing it back as 25fsp. I checked so premiere read the metadata correct and is says 25fps inside premiere. So Premiere should only need to playback 25fps in 3k that is "scaled to fit" at full debayer. This works so great with the 4k files.

As you say, 3k is less data than 4k! Why on earth is 3k files so heavy in comparison? Do you have smooth playback in premiere on your 3k files?
 
Joel Arvidsson said:
Yes I playback 4k smooth with fulldebayer. But i have checked the "scale to fit" option. So premiere throws away alot of info.
Click to expand...
Hey Joel - I'm not sure that it's entirely true that premiere is throwing away a lot of info. Or at least, that probably needs some clarity. I have always been under the impression (for RED footage) that 'scale to frame size' affects how Premiere downscales footage. That is to say, I think that if you are selecting full debayer, Premiere is still doing full a debayer but then down-scaling it in a way that is less processor intensive.

The exception to this rule is when you are exporting - if you have used "scale to frame size" and also do not check "max render quality", then I believe Premiere will also debayer at the most performance appropriate resolution (ie, it may not be a full debayer). I don't really have anything to back this up except performance benchmarks and tests I have run in the past.

What are the specs of the system you are running on?

As you say, 3k is less data than 4k! Why on earth is 3k files so heavy in comparison? Do you have smooth playback in premiere on your 3k files?
Click to expand...
Will have to check for you - away from the edit computer at the moment :P. I don't think I would get a full debayer on 3k in realtime - as 4k works best (realtime - no skipped frames) at 1/4 for me. I would expect to be able to get a 1/2 debayer from 3K footage without too many issues though. Will have a look :)
 
Im running a dual xeon 2687w, 64g ram and with a gtx690 and my raid is between 430-550meg s read/wright dependent on how much stuff is on it. Im still trying to get bmd to fix what the promise on ther webbsite to let me work in 4k timeline and have the declink 4k extreme to scale down the output to 1080 but thats another story.
 
Brad Allen said:
The exception to this rule is when you are exporting - if you have used "scale to frame size" and also do not check "max render quality", then I believe Premiere will also debayer at the most performance appropriate resolution (ie, it may not be a full debayer). I don't really have anything to back this up except performance benchmarks and tests I have run in the past.
Click to expand...

I wish adobe would chime in and clarify exactly what these options do. The only definite answer in writing I have seen is the scaling algorithms which PPro uses for max render quality...which remain unchanged with CUDA cards whether you have max render quality checked or not.

I don't argue your testing, I am sure you have seen a pattern that would lead towards that theory...I just wish we could get absolute clarity from adobe.
 
Joel,

Just for kicks...try throwing the 3k in a 24fps time line and interpret the footage to 24fps instead of 25

I use high speed 3k all the time and no issues....I am wondering if the stuttering is an interpretation issue with the playback
 
You must log in or register to reply here.
Back
Top