F3: Off-speed recording with external recorders?

Grug

Grug

Veteran
Hi guys,

I've got a few shots I want to get in 22/23fps on the F3. Now I can easily set the camera to record those frame rates internally to the SxS cards, but I want to record them with the PIX240 via HD-SDI.

Does anyone know how the camera outputs these sorts of off-speed frame rates (or if it's even capable of doing so)? Do they feed out of the HD-SDI in a 25p wrapper? And if so, how can they be adjusted/conformed to net fast-motion when played back at 25fps?

Any info or suggestions would be much appreciated.

Cheers
 
When I need to record externally anything else from 25p I use the normal SDI output. I guess you can get 23,97/24/25/30/50/60 recorded and if you use the SR1 recorder I think you can do all sorts of 1080 frame rates from dual link. Playback is at the frame rate selected so even 50p wont playback at 25fps unless you use the Q&S function and record internally.

Often, if there's just a few clips, I record them internally with the Q&S function to check clips on set.
 
Sorry Osslund, by "normal SDI output" do you mean the HD-SDI 'A' port in the centre? Or the 'SDI OUT' port at the top right of the rear of the camera?
 
As an owner of both a Sony F3 and the Sony SR-R1 I can answer this question. For reference sake I also own the Samurai, but have not personally used a Pix.

The Sony F3 is capable of outputting 17-60fps 1080p through the dual link SDI outputs. What you need to understand is the following:
1. This is not itself a selectable option - it's something that occurs automatically when the dual link outputs are active AND you're using the camera's S&Q settings.
2. The wrapper will either be 1080 50p or 60p, depending on PAL/NTSC. The real frames you want are mixed in with a bunch of frames you don't.
3. The only recorder that I know of which can properly extract and record just the "real" frames is the Sony SR-R1. Other recorders just see the 50p or 60p output.


As for the timebase, you have to select that on the recorder. On the SR-R1 you can program it for playback at your preferred speed.
 
Grug said:
\And if so, how can they be adjusted/conformed to net fast-motion when played back at 25fps?
Click to expand...

They can't.

As James said "The real frames you want are mixed in with a bunch of frames you don't.". You'd need some software to pick out the unique frames apart from the padding frames, and as far as I know, it just doesn't exist.

Only way to do it, like they said, is R1 recorder.
 
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Furthermore, while the current Pix 240 firmware does support RGB 4:4:4 up to 30p, it does not support 1080 50p/60p. That's my understanding anyway. Clearly, the hardware can handle a 3G signal, but for some reason or another they've not gotten 1080 50p/60p worked out.
Being able to receive 1080 50p/60p is a prerequisite for a recorder to properly handle the Sony F3 variable frame output. For a recorder that can handle the format, additional firmware would need to exist to catch the SDI flags that determine which frames are real and which ones are garbage. Right now no one has done that other than the SR-R1 to my knowledge.

I also own a Sony F35, which has a similar feature, but I can tell you they are at least slightly different.

Unfortunately, the flag data doesn't get recorded in the video stream, so you can't use it for a post processing frame removal tool.
 
Correct. The only way to do this is with the R1 recorder. The Nanoflash can be set up to record over/undercranked footage.

Ned Soltz
 
You know, an inelegant solution to this problem does exist. Since the Sony F3 can record the 720p version internally, you could use that file as a reference for either a manual or automated frame removal in post. The automated removal might have to rely on some visual analysis algorithm.
 
Thanks fellas, guess I'll have to make do with 22fps recorded internally. I might try recording 24fps and speeding it back up to 25fps, but I fear that'll be a bit subtler than I was hoping for.
 
Speeding up a clip is not as bad as slowing down in post. Sure, nothing replaces doing it in camera, but I've also research about slowing down to 35 fps and I've gotten the same answers you got here.
Try using Motion to do it. I would assume it should come out to 4% per frame. Original shot at 25p 23 fps should be 108%.
The internal recording is not that bad either. The camera can internally do 1080p from 30 fps down.
 
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