-
60fps in PPro CS5 and Quicktime player
Dear all –
This is more of a curiosity question more than anything, as our team’s brute-forced a solution to the problem. We’re just wondering if anyone could shed some light on the logic behind the problem. I’ll list this out as clearly as possible:
1) We’ve received a batch of video files which needed to be edited; these were clips from a surgical procedure, and naturally we don’t have any info on the camera it was captured on. What do know is the video files are:
1920 x 1080, pixel aspect ratio 1.0.
H.264 encoded, in an mp4 container.
59.94 fps.
Datarate of about 17Mb/s.2) When we play these files in Quicktime/VLC, going through it frame by frame there doesn’t seem to have any comb artifacts, so we assume it’s progressive.
3) We then specified a sequence to start editing the footage in Premiere Pro CS5, matching the settings (1920 x 1080, PAR 1.0, 59.94 fps progressive). We imported the footage via the media browser, and started editing away. As we previewed the edited clips though, the playback was way too fast, as compared to playback in Quicktime/VLC.
4) It was only when we forced the footage in the project to be interpreted as 29.97fps that we got the smooth playback back. We then rendered these clips with the Quicktime Animation codec, and imported those into After Effects for final editing (adding in labels and figures). Everything looks fine and dandy from this point on.
Our question then, is why did PPro play the edited footage back at a doubled-rate? Or, why did QT/VLC play it back at a half rate? When we imported the footage via media browser, the option ‘Use Frame Rate from File’ was set, and it was set to 59.94 – was this the actual frame rate it was recorded at? Or was it recorded originally in 29.97, and somehow the camera (which we know nothing about) artificially set it to be 59.94, even though it’s not…?
Thanks for your input.
-
3 Replies
-
Would it be possible that the file was actually interlaced 29.97fps?
-
On closer look in PPro, it does seem the footage is interlaced – I apologize for the confusion.
Does that mean that when QT, and PPro as well, mean 60 fields per second…? And I should read that as, this footage is 29.97 frames per second, interlaced, and recorded at 59.94 fields per second (2 fields per second, thus combining into one full frame per second)?
-
Yeah it’s probably 59.94i and that’s basically interlaced 29.97. Like 50i is actually 25fps not 50fps.
Reply to this Discussion! Login or Sign Up