Forget all the things I said in the other blog entry. I had to mess with the numbers because of the limitations of the software I'm using. It is called AVIdemux. I do not recommend it. It is just the only one I can get to do resampling of frame rates. Yes, yes, I know there are 50 better programs for this. This is the one available and running for me at this time. The idea is about the same though. If you don't have a button that says something like "Turn this video in to a time lapse." Then you have to play with the numbers until you get what you want.
Basically, I want to take 108,000 frames, select 900 or so frames, then make them play at 30 frames per second. Easy as pie. Now, imagine making a pie with the wrong kind of pan, no mixing bowls, measuring devices that start at a gallon, open flame only, and only your hands for implements. Lets get started.
The frame rate I am working with is 30 frames per second.
|1 sec||:||30 frames|
|1 min||:||1800 frames|
|1 hour||:||108,000 frames|
It is very important to remember that there are two frame rates. Input and output. The frame rate under Video -> Frame Rate affects the input frame rate. That is the frame rate the clip you drag and drop in to the clip window is read at. The frame rate under filters affects the output file. That is the frame rate all players will play the finished product at once it is made. We will play these two against each other to trick the software in to making a time lapse movie by double running the video through the software.
- Open your hour long video
- Click Filter below Video. This software requires you to re-render the video in order to filter it in any way. POS!
- Scroll down to "Re????? FPS", highlight it and click the plus sign at the bottom of the window.
- Set the frame rate to 1 frame per second. Note, this will still give you something like 4000 frames. Too long for me. This software will only go down to 1 frame per second. POS! Click OK after adding the filter.
- Go to video menu and set Frame Rate to 90 (3 times normal rate) or 120 (4 times normal rate) fps to make the input play faster than it would normally in order to shrink the number of frames further. The max is 200 FPS in this software. POS!
- Render the temporary video and note the number of frames that it calculates. The number should line up as per the table above.
- Once you have rendered the temp video, open that video in the software and set everything to copy under video and audio. I typically mute the audio on time lapse videos. Under the video menu set the frame rate to 30 fps.
- Render the final video.
Or you can find that magic piece of open source software that has a button for this, that works in Linux. I'm not holding my breath, but it might be out there.
Or you can use any number of Windows and Mac video editing software packages that have a button for this sort of thing.
Or you can buy the $2.50 Android app that makes a time lapse from your phone's camera with a couple clicks.
Or your video camera might have a function that does it for you.
I love Linux.