Create time lapse video from other video - ffmpeg

Using avconv (or even ffmpeg, so I can use as a reference), how can I create a time lapse video by taking only anchor/reference frames from another video? Most information I find is on how to create a time lapse video by combining images, and I'd like to do it by extracting frames from a video. Say, if a video is 30 seconds long at 30 FPS, I'd like to take 60 out of those 900 frames (900/60 = every 15 seconds) to produce a 2 second video.

To take every 15th frame, use
ffmpeg -i in.mp4 -vf select='not(mod(n,15))',setpts=N/FRAME_RATE/TB out.mp4
Another method is to use the framestep filter
ffmpeg -i in.mp4 -vf framestep=15,setpts=N/FRAME_RATE/TB out.mp4

I had a H264 video from a camera and after lots of attempts found following command that produce 16x faster video with good result and 60 FPS (option -r) that is good for the YouTube timelapse
ffmpeg -i video.avi -r 60 -filter:v "setpts=0.0625*PTS" -vcodec libx264 -an timelapse.avi
You can check the result here https://www.youtube.com/watch?v=azhRqKQ7kCU
Since you are asking for 1/15 frame it will be 1/15 ~= 0.06667 with 30 FPS result video you will need command
ffmpeg -i video.avi -r 30 -filter:v "setpts=0.06667*PTS" -vcodec libx264 -an timelapse.avi

Related

Timelapse (1/6 fps) from slo-mo (240 fps) with ffmpeg

I recorded slo-mo video on an iPhone SE (2) by mistake instead of timelapse.
I know there's a lot of answers to this question here, but I'm trying again and again and always something's wrong (like a video that has a correct total no. of frames, but lasts 3 hours and is basically a freeze :D )
My recent command was
ffmpeg -i IMG_2174.MOV -vf framestep=1440,setpts=N/120/TB -c:v libx264
-preset slow -crf 22 -an -r 30 IMG_2174.timelapse.MOV
but it resulted in a one-second-long video, so way over-timelapsed. Should be several seconds IINM. The source video is 30 minutes long #240fps, 17GB.
Thx.
This command seems to do the trick:
ffmpeg -i IMG_2174.MOV -vf framestep=1440,setpts=N/30/TB -c:v libx264 -preset slow -crf 22 -an -r 30 IMG_2174.timelapse.MOV
Here is the explanation for OP's self-answer.
ffmpeg -i IMG_2174.MOV
-vf framestep=1440,setpts=N/30/TB
-r 30 -c:v libx264 -preset slow -crf 22 -an IMG_2174.timelapse.MOV
Given input video at 240 fps cfr:
framestep=1440 keep every 1440th frame, yielding 240/1440 = 1/6 fps
setpts=N/30/TB speeds up the video by x180 (30 / 1/6)
-r 30 output option: match the new pts interval set above
For a vfr video, framestep=1440 likely results in incorrect timing (though on the average correct). For such video, replace the framestep filter with fps=1/6 filter so it picks the frames based on pts rather than frame count.
[edit note: iPhone's slo-mo recording does keep 240fps cfr so the OP's solution is 100% correct, edited down just to mention a vfr-correct approach]

How to create a full length video from images with FFmpeg?

I have more than a thousand images that I want to transform into a 3 minutes video. I tried using this line ffmpeg -r 30 -i "E:/White-box-Cartoonization/test_code/cartoonized_images/$flower%03d.bmp" -c:v libx264 -pix_fmt yuv420p out.mp4 it worked but creates only a 5 seconds video. What do I need to do to turn it into a full length 3 minutes video?
If you have 1250 images and want an output duration of 180 seconds:
ffmpeg -framerate 1250/180 -i input%03d.bmp -c:v libx264 -vf format=yuv420p output.mp4
This example results in a frame rate of 6.94. Some players can't handle such low frame rates. If your player does not like it then add the -r output option to make a normal output frame rate. ffmpeg will duplicate the frames but the output will look the same.
ffmpeg -framerate 1250/180 -i input%03d.bmp -c:v libx264 -vf format=yuv420p -r 25 output.mp4
For 3 minutes of video at 30 frames per second (-r parameter) you'd need 30*60*3 images: 5400 images.
Your source parameter specifies there would be only 3 digits, so you have a maximum of 1000 source images:
$flower%03d.bmp => $flower000.bmp .. $flower999.bmp
1000 images at 30 frames per second should give about 30 seconds of video ... if you actually have $flowerxxx.bmp files.
You might need a 4th digit in there somewhere.
$flower%04d.bmp

Converting video from 60 FPS to 25 FPS without slowing it

I am trying to encode video through ffmpeg in Linux system. Original video has 60 FPS and I need to change it to 25, but when I do so, video is slower than original.
When I change it to 30, everything is fine (I guess it's easier for encodder to play every second frame than compute it to 25). How can I achieve that video will have 25 FPS with same speed as original video?
Currently I am using this command:
ffmpeg -i "test.mkv" -r 30 -vcodec libx264 -x264-params keyint=10:scenecut=0 -an -bsf:v dump_extra -video_size hd720 test2.mp4
Thank you for your help!
What does "video is slower than original" mean?
I try this:
ffmpeg -i BQTerrace_1920x1080_60.mp4 -r 25 -vcodec libx264 -x264-params keyint=10:scenecut=0 -an -bsf:v dump_extra BQTerrace_1920x1080_25.mp4
The output video isn't slower than original video, but it looks more unsmoother than original video. This is because that the output video has less frames than original video per second.
In my case, the total frames, frame rate, and video time are:
BQTerrace_1920x1080_60.mp4: 600 frames, 60 fps, 10s
BQTerrace_1920x1080_25.mp4: 250 frames, 25 fps, 10s

FFmpeg Slideshow issues

trying to get my head around ffmpeg to create a slideshow where each image is displayed for ~5 seconds with some audio. created a bat file to run the following so far:
ffmpeg -f image2 -i image-%%03d.jpg -i music.mp3 output.mpg
It gets the images and displayes them all very fast in the first second of the video, it then plays out the rest of the audio while showing the last image.
I want to make the images stay up longer (about 5 seconds), and stop the video after the last frame (not playing the rest of the song), are either of these things possible? i could hack the frame rate thing i guess by having hundreds of the same image in order to keep it up longer, but this is far from ideal!
Thanks
The default encoder for mpg output, mpeg1video, is strict about the allowed frame rates, so an input and an output -r are required:
ffmpeg -r 1/5 -i image-%03d.jpg -i music.mp3 -r 25 -qscale:v 2 -shortest -codec:a copy output.mpg
The input images will have a frame rate of 1 frame every 5 seconds and the output will duplicate frames to reach 25 frames per second.
-f image2 is generally not required.
-qscale:v can control output quality. A sane range is 2-5.
-shortest will make the output duration the same as the shortest input duration.
-codec:a copy copy your MP3 audio instead of re-encoding.
MPEG-1 video has more modern alternatives. See the FFmpeg and x264 Encoding Guide for more info.
Also see:
* FFmpeg FAQ: How do I encode single pictures into movies?
* FFmpeg Wiki: Create a video slideshow from images
You could use the filter fps instead of output framerate
ffmpeg -r 1/5 -i img%03d.png -i musicfile -c:v libx264 -vf fps=25 -pix_fmt yuv420p out.mp4
This however skips the last image for me strangely.

ffmpeg keyframe extraction

I have been trying to extract keyframes from video using ffmpeg 0.11.1 . So far all the commands I have tried do not extract keyframes but return all the frames ie 25fps*total time number of frames in the output.
I tried setting the keyint_min as 25 to make sure there is a amximum of 1 keyframe per second.
ffmpeg -vf select="eq(pict_type\,PICT_TYPE_I)" -g 250 -keyint_min 25 -i C:\test.mp4 -vsync 2 -f image2 C:\testTemp\thumbnails-%02d.jpeg
But still all the frames are returned.
Then i tried, to separate the keyframes by 20 seconds.
ffmpeg -i C:\test.mp4 -vf select='eq(pict_type\,I)*(isnan(prev_selected_t)+gte(t-prev_selected_t\,20))' -vsync 0 -f image2 C:\testTemp\%09d.jpg
Again same result, all the frames are returned.
What should I do?
In your first command you are using the filter as an input option. I don't know how ffmpeg will interpret that.
Try this:
ffmpeg -i C:\test.mp4 -vf select='eq(pict_type\,I)',setpts='N/(25*TB)' C:\testTemp\%09d.jpg
Change 25 to the frame rate of your source: 30000/1001 for NTSC video, 24000/1001 for NTSC film, 25 for PAL, etc.
Control output quality with the -q:v or -qscale:v option (just called -qscale in old ffmpeg). Range for mpeg* is 1-31 where 31 is the worst quality.
Next time remember that ffmpeg usage questions are to be asked at superuser.com since stackoverflow is specifically for programming.

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