Convert multiple AVI files to JPEG

Question

I am trying to convert multiple (250 or so) .avi video files into .jpeg files with R.

I have managed to convert single .avi files using function av_video_images() from library av, but I would love to know how to iterate this over multiple input files.

av::av_video_images("FILE001.AVI", destdir = "Site_1_JPEG", format = "jpg", fps = 1)

I have the 250 .avi files in a folder and would like all frames produced in the output folder Site_1_JPEG.

Answer 1

This is not a complete solution since I cannot reproduce your issue, but I think it will get you closer. Your example suggests that the files you want to process are in your current working directory. Secondly, your code will not produce the desired results because av_video_images names the .jpg files as "image_000001.jpg", "image_000002.jpg", "image_000003.jpg" and I see no way to alter the names of the extracted jpg's. That means your code will successively overwrite the previous files and at the end you will only have the final set of jpg's. To prevent that you need to create separate folders for each video file. Here is one solution:

library(av)
sapply(flist[1:3], function(x) av_video_images(paste0(path, x), x, fps=.5))

To test the code I specified that only the first 3 files will be processed to check things out. There are two differences between my code and yours. First my video files are located in a different directory (path) so I pasted the path onto the file name. Second I provided a different destination directory for each file which is just the file name. This produced three folders with jpg files in each.

The error message could indicate that one or more of the .avi files is corrupt. You can get the directory information on all of the files with

file.info(flist)

The main thing to look at is the size column to make sure the size is large enough.