Video sampled in 50 FPS instead of 25

[Mike Velte]

As a workaround till you find the camera settings;
Right click on the problem clips in the Project window and choose Interpret Footage and then Assume this Frame Rate=25.

[Amir Shachar]

I know this solution, but this way I cannot use the sound of this video – it gets distorted. Is there a way to make sure it alwayes samples in 25 FPS? And why does it somtimes encode in 25 FPS and sometimes in 50?

Thank, Amir

[Mike Velte]

Video capture via firewire is simply data transfer from the tape…no changes made. Premiere does not change the properties of your video, including frame rate, or interlaced or progressive regardless of your project settings.
Both 25p and 50i are valid HD frame/field rates. I suspect a setting in the camera has been changed, or if 2 cams, they did not match.
weird!

[Amir Shachar]

Hi,
Well, it seems to be more complicated than that. Here is the full story: I’ve tryed to sample *the same tape* on a number of devices (4 cameras, 2 VTRs), and got mixed results: sometimes it sampled in 25 FPS and sometimes in 50. I noticed some locations on the tape that when I sample before them, I get 25 fps, and when after them, 50. As far as I know, the camera setting were not changed. Me and my friend devied a theory: perhaps the “jumps” in the timecode, that occure when the camera is shut off(i.e. when changing batteries) have something to do with that. What is your opinion?
Thanks, Amir

[Mike Velte]

Turning the camera off and back on does not create a break in SMTE timecode, other than the date/time info also recorded on the tape. What does however is turning the camera to VTR mode after recording a scene, then previewing up to AND PAST the end of the recorded scene. Now this break could cause the camera to switch frame rate especially if the tape was previously used.

If I am correct (50-50), there is not much you can do to correct the video…it is simply data transfer from the tape without any sampling done anywhere in the process.