Attempt of automatic speed adjustment of time-lapse movie (Part 1)
motivation
I rented a car a little in the United States in the summer I bought a suction cup mount and took pictures at regular intervals. (I think it was every 5 seconds)
Below is the first half of the Lime Laps on the way from Chicago to Pittsburgh.
The bar at the high speed gate does not go up near 0:34 and is backing up.
Play slowly where such an event is occurring
Plays nicely fast where other endless roads continue
I wanted you to do something automatically.
However, I feel that the service area of 1:08 is a little too long.
It's about 2 seconds, but it's long, so I'd like to make it about 1 second at the longest.
https://youtu.be/BOHDtW9_tlQ
ffmpeg
Generate video from serial number image with ffmpeg / Generate serial number image from video ~ How to prevent dropped frames ~ --Qiita I made a video with reference to the above site.
ffmpeg -framerate 30 -start_number 416 -i ./data/images/001/DSC%05d.JPG -vframes 6000 -vcodec libx264 -pix_fmt yuv420p -r 60 out.mp4
Suppose the images you want to time-lapse are from DSC00416.JPG to DSC03415.JPG.
Output video using 30 images per second with a frame rate of 60
Since one image is used twice, I think it means a total of 6000 frames.
I think you don't have to specify the -vrames option, but I specified 180 when I wanted to do a small test.
$ ffmpeg --help | grep -E "(-framerate)|(-start_number)|(-vframes)|(-vcodec)|(-pix_fmt)|(-r )"
-pix_fmts show available pixel formats
-vframes number set the number of video frames to output
-r rate set frame rate (Hz value, fraction or abbreviation)
-vcodec codec force video codec ('copy' to copy stream)
$ ffmpeg -pix_fmts | grep -E "(FLAGS NAME)|(yuv420p )"
FLAGS NAME NB_COMPONENTS BITS_PER_PIXEL
IO... yuv420p 3 12
See ffmpeg --help full for details.
phash
Previously, when I searched for similar images
A brief summary of similar image search --Qiita
I used the library that uses phash introduced above from ruby.
This time I wanted to link using ʻopencvfrom python, so I searched for one that can usephash` from python.
https://github.com/JohannesBuchner/imagehash
was.
Plot the hash value distance between each frame
I tried to match the time-lapse movie.
The middle is phash.
https://youtu.be/oIoNYs4yLio
The sky is hiding in the bridge and it's blurry sweat
I want to extract this area. .. ..
I want to shorten here! (I feel like this is good)
To the second part
I'd like to decide the window size and try various things such as local distribution. To be honest, I think there are people doing the same thing It's information gathering before spending time.
reference
- ffmpeg
- Install ffmpeg from Homebrew. Export one still image from the video. | Miscellaneous notes BOOOKs
- phash
- To know the atmosphere 2. To know the hash algorithm in the table in 1.