What I'm doing:
I'm still working on my slideshow script. Meaning, I use ffmpeg's concat demuxer (files.txt) to provide ffmpeg with a bunch of
.jpg files for a slideshow.
In the past I wanted all images to be shown for 3 seconds each, so I used (misused?) ffmpeg's framerate flag
-r 1/3 to achieve said duration, which worked out perfectly and really fast (roughly 10 seconds for all 600 images).
What I want to do now:
Now, I wanted the slideshow to be more dynamic by varying the duration (longer for more interesting ones and so on, you know). So, I decided to ditch the framerate flag and set the
duration 3 right in the concat file. Of course, for each file with the correct number of seconds. Which works - kind of.
My only problem is: Now it takes ages for ffmpeg to run through that script. Not only by a little, but it takes about 30 times as long. Even though i already use
-c:v libx264 -preset ultrafast.
So, it's no longer really practical to use. Do I miss something or is there a third method?
Just noticed ffmpeg drops this warning:
More than 1000 frames duplicated. Which can't be the case, when a static image is shown for a maximum of 5 seconds at 25 fps (default value).