Posts tagged time lapse
A five second video I made today from the footbridge of a Hull to Bridlington train stopping at the station in Driffield. As the train arrives in the station you can see the level crossing barriers behind it go up and traffic resume.
I have worked out a method to allow zooming and panning for time lapse movies. More work is still needed, but here is a short sample of storms last Saturday.
A time lapse video can be made to look really good if the camera is panned while the picture taking happens. The result is smooth motion during the video, and there are plenty of examples of this on You Tube.
There are lots of ways to make cheap panning mechanisms, with the most popular involving an old egg timer. However these approaches have some limitations:
- Once the panning starts you don’t stop it, even if you panned away from an area where something happened 10 minutes after the start
- The panning is typically a linear motion – the same speed all the time
- Most panning mechanisms do not have vertical panning, only horizontal
Number one comes from the limitation of having to set up the motion before starting to take the pictures. It can be difficult to anticipate in advance what might happen in the scene and once it does even if the motion was somehow changed, it would have to change slowly to avoid disrupting the video in a jarring way, missing the item of interest anyway.
Number two can be solved by using a PC or microcontroller to control the camera motion in more complex ways. However this is added time and expense for design and setup.
Number three can be solved by using two motors, one for horizontal and one for vertical. Again, unless the motion is very simple and defined in advance, a PC or microcontroller would be needed.
Another time lapse, this time of a trip I took yesterday. Created using a Canon A480 and CHDK.
Here is another time lapse of storms building over the Santa Catalina mountains. The black specks that keep appearing are birds going to and from our bird feeders.
It was generated with 3750 pictures taken two seconds apart using CHDK.
CHDK is an alternative firmware for some Canon cameras. It provides access to lots of cool features that are found only on high end SLR cameras, plus some features that are not found anywhere.
Why the Canon A480? Because refurbished cameras are available for $75 from Adorama with a one year warranty and only one version of firmware has been seen on them to date. This means that there is a very good chance the firmware in the A480 you receive will be compatible with CHDK.
This short guide shows how to quickly access some useful features. It is not intended to be exhaustive or replace the CHDK wiki or forums.
CHDK can be set to automatically load when the camera is turned on, however I don’t use that feature because I want to use an 8Gb SD memory card. Cards of 8Gb create complications when autoloading CHDK, but I want the extra space for long time lapse photography.
Recently I had the need to take a set of jpeg images and convert them into a high definition time lapse video, then upload to You Tube. Easier said than done…
To get the best quality I wanted to use H.264/MP4, which is also recommended by You Tube. I also wanted 1080P. The problem is that You Tube doesn’t seem to like B-frames in the file, and messes up the start of videos. So here is the solution I found.
Firstly I needed to upgrade my Debian server to Squeeze.
Next I compiled x264 and FFmpeg as described in How To Build FFmpeg on Debian Squeeze.
Finally I ran the following FFmpeg command line to generate a time lapse video at 24 frames per second (-r 24), using 1080P (-s hd1080) with no B-frames (-bf 0):
ffmpeg -r 24 -i %04d.jpg -s hd1080 -vcodec libx264 -vpre hq -bf 0 -crf 16 myfile.mp4
It’s important that the frame rate is specified before the input source in order to make FFmpeg apply the frame rate to the source. Note that trying to use qt-faststart causes You Tube to complain about the audio, even though there isn’t any audio.