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  #1  
07-24-2017, 03:29 AM
BrandoL10 BrandoL10 is offline
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Hello,

I am currently editing videos originally shot on an iPod Touch 4G. All of them have variable frame rates that average around mid-high 20s (29.09, 28.14, 27.96 etc) and always max out at either 30, 31.579, 33.333 or 35.294fps. I use iMovie '11 and export using quicktime. Is it possible to match the exact frame rate of the source or do I have to convert to a constant frame rate? If the latter, average or a standard frame rate? The intended delivery platforms are YouTube and DVD. Am willing to try different programs if the solution is not possible in iMovie, whether Mac or PC.
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07-24-2017, 12:29 PM
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lordsmurf lordsmurf is offline
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That doesn't make any sense. The bitrate can be variable, but not framerate.

If that really is how it recorded -- and that is horrible -- then you're screwed. You have to select a standard framerate, and Youtube will also insist on one. If it truly is variable as you say, the audio will never sync.

DVD is especially strict.

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07-24-2017, 04:38 PM
sanlyn sanlyn is offline
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Yes, indeed, many phones record video at variable frame rates (VFR), which has been described as a solution looking for a problem. At any rate it's yet another clever way that the likes of Apple make huge profits by lowering video and audio quality for the clueless masses. In this respect, using iMovie to re-encode iphone video to QuickTime (if it wasn't QuickTime to begin with) is another quality hit. My own view is that I'll never understand why people insist on using a Mac with the idea of video repair and restoration in mind. I guess there are quality-preserving ways to do it that way, but I haven't seen anything posted yet.

It's supposed to be pretty easy to transfer iphone videos to a Windows PC, for most iphones anyway that can connect to a PC via USB cable. Plug the USB into the PC an Windows autoplay will detect the phone as a storage device and start looking for pictures, music, and videos. Windows will these items in the Explorer dialog and allow you to import them as-is without modification in their original format.

Once you have your video transferred I see where users suggest three software products that can re-encode at decent bitrates and good quality and correct the frame rate to 23.97 NTSC with correct audio sync. This assumes that your video is a DVD or BluRay compliant 720x480 at either 4:3 or 16:9 display aspect ratio-- if it isn't, you're asking your software to do some extra stuff, but it will work in the end. Some free editors/reencoder packages like HandBrake have been tried, but they either produce non-compliant video or can't sync up the audio.

Two paid products that can do this properly are TMPGenc Video Mastering Works and ULead (now Corel) VideoStudio products. They can output synced-up video at the correct specs for the disc output you want. They can handle output for web posting as well, but you're talking about two different processing paths. The no-cost way can offer somewhat higher quality: use free Avisynth's DirectShow file decoder or any of several other decoder plugins to decode the original into lossless media and to correct the frame rate and audio sync, as well as to check the correct frame dimensions, then encode using your favorite encoder and authoring/burning program. Avisynth can format for DVD/BluRay as well as proper web posting, which have different encoding requirements.

The program mentioned are all Windows apps.

Last edited by sanlyn; 07-24-2017 at 05:35 PM.
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