I sometimes get back home with tens of gigabytes of image data distributed across thousands of photo files. This is when the actual work starts: sorting, labeling, selecting, agonizing over finding the best shots, and developing them.
This time I also wanted to make a “time lapse” video of all undeveloped photos I took. A nice little short film of all scenes I tried to take photos of. An attribution to all those photos that otherwise would end up in the photo graveyard — in the archive, never going to be looked at again.
For converting a series of JPEG image files into a properly encoded video the open-source program of choice is ffmpeg. Building up an appropriate ffmpeg command took a while. Here is the command I used:
ffmpeg.exe -f image2 -framerate 8 -i resized_renamed_2560/resized_%05d.jpg \ -filter:v "scale='min(2560,iw)':'min(1440,ih)':force_original_aspect_ratio=decrease,pad=2560:1440:(ow-iw)/2:(oh-ih)/2" \ -c:v libx265 -crf 28 -preset medium video-2560-h265-medium.mp4
The video filter syntax (the part after
-filter:v) instructs ffmpeg to output a video with 2560 pixels width and 1440 pixels height, retaining the aspect ratio of the input image files. That last bit is important because in a large set of photos we usually find two different aspect ratios: we shoot most photos in landscape orientation, but others in portrait orientation. Putting both into the same video means that one of both types needs to be treated in a special way. The video is going to have the same aspect ratio as my landscape photos, so they are not treated in a special way. For portrait photos, though, the above command will retain their original aspect ratio by making the longest edge fit, by putting the image at the center of the video, and by filling the empty space at its left and right with black padding. Kudos to this and that.
-framerate 8 is an arbitrary choice, it means that I want to have 8 of my input images per second of output video.
I ran ffmpeg on Windows (which is the platform I process my photos on, mainly with Lightroom).
Here is how I generated the JPEG files used as input for ffmpeg in the first place:
- I first used a proprietary Sony program (Imaging Edge) for batch-converting my ~2500 raw (ARW) photos to JPEG files, with full resolution. I would have loved to use an open-source program for that. However, that is not recommendable. The goal here is to get reasonably good-looking JPEG images from the camera’s raw files despite not manually developing them. Automatically converting a camera’s raw image to a JPEG image already implies that the result looks crappy to a certain degree (contrasts, white balance, colors — all of that will just be flat, mediocre, a middle ground). In the spectrum between a really crappy outcome and a not-even-so-bad outcome the proprietary software simply does the best job.
- I then used IrfanView for batch-processing the JPEG files from the previous step into JPEG files easily digestible by ffmpeg. Specifically, I down-scaled (longest side being 2560 pixels long, towards the desired video dimensions) and renamed (zero-filled, consecutive 5 digit counter in the file name). Corresponding to the
resized_%05d.jpgin the ffmpeg command line shown above, the files were named like this:
resized_00001.jpg resized_00002.jpg resized_00003.jpg resized_00004.jpg ... resized_02583.jpg