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Thread: Speed Edit Math Dilemma with FPS (frames per second)

  1. #1
    He said "member" Kurt_Henning's Avatar
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    Speed Edit Math Dilemma with FPS (frames per second)

    I seem to be in a dilemma. A sync dilemma.

    I have some footage which appears to be 30 fps, and most of the footage is DV at 29.97.

    After I sync the feeds, they slip inside the first minute. I imagine changing the speed would address this, but I also would guess that there is an equation to do this correctly.

    I have a master capture (this is a guitar trick instructional video). We used a TCP v2 to switch between 3 cameras (wide shot of talent and two other angles into the TCP.) There were 3 other cameras also. These were ISOed and recorded to tape, but we also use two laptops and captured to disk using SpeedEDit 1.55 and the SHQ saver, I believe, but perhaps the MS DV.avi. The Mac was our third "recorder." That is not currently in the mix, for a couple of reasons. First, the capture was 640 X 480. SpeedEDIT could care less. When I added that file, it stretched it, or loaded it properly, and it looks just fine with the other feeds.

    For now, I am only dealing with the NEwtek captures.

    Here is what I have

    1. TC captures that are .MPG
    2. SE captures that are .avi

    This is a musical piece with dialog so it's pretty easy to mark the clips and line them up for syncing purposes.

    Part 2 of the project was shot in November 2008. We shot the first part in July 2008.

    Most of the July footage is synced and we did not encounter any of these problems. On the July shoot, I did have to record to tape and digitize two of the feeds, but otherwise we are getting as much as possible direct to disk.

    As a video guy, I HATE capturing. I like editing. I get myself (like many others) where I may have 20+ hours of footage to capture. Even in the studio, I have enough decks/cameras to capture to TCP, SE, or 2 installs of VTSE 5.2b. So, I can capture 4 different camera feeds at the same time, and then use the captures over the network. But if I can just start cutting, that is my preference.

    If you can follow my post and have any ideas, or the actual equation, I would love to learn the stuff, and either speed up or slow down one of the feeds a fraction of a percent.

    IF anyone else has ran across this, please share your teknique to solve this issue.

    So far, there is about 13 hours of footage "live switched" and the July cuts are synced. But the November clips are kicking my butt. I can see the waveform and realign the clip to sync it, but I will have to do this 100s of times and I really may be into 1000s of times.

    In closing, where did we go wrong during production? I can't change the frame rate of the TCP capture, so that is fixed. I have captured SHQ or DV.avi files from Speed EDIT many times and have even edited onsite with the feeds before. What that happens, Newtek really shines.

    this time around, I need a buffer pad to shine this baby up.

    Thanks to anyone who has a theory. A colleague mentioned that perhaps the cameras should have been genlocked. The "switch" does not have issues (on the TCP I captured the program out, not the FX row). I am stumped, and besides Newtek engineering, this group is the next best "smartest people in the room," whom I could tap for some expertise.
    is appreciated

  2. #2
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    This would be the equation:

    29.97 / 30 = 99.9% play back speed.

    But actually dropframe (29.97) is 29.97003 so your playback speed to match should be 99.9001%

    Then they should match.

    Lookup SMPTE timecode in Wikipedia

    http://en.wikipedia.org/wiki/SMPTE_time_code

    Didn't read past your first few lines, sorry - had to go.

  3. #3
    'the write stuff' SBowie's Avatar
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    30/1.001 = 29.97 ....
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    Regards, Steve
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    ("You've got to ask yourself one question ... 'Do I feel lucky?' Well, do ya, spammer?")

  4. #4
    VT5 USER Rich Deustachio's Avatar
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    I found if I need to capture long form clips I use Type1 instead of Type2 to avoid the loss of sync.
    Dynamic Video Productions
    Mount Laurel NJ

  5. #5
    Find a "hot frame" at the beginning and at the end of each clip, set markers alt strechth WALA BIG GAZOOMBAS!

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  6. #6
    Use the speed/scale/fps option (F8) in the clip properties to change your clips fps.
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