[FFmpeg-user] make a slideshow out of images and embed videos in it

[Moritz Barsnick]

On Mon, Apr 06, 2020 at 17:23:45 -0500, atticus via ffmpeg-user wrote:
> Now if I run the command to concatenate the slideshow with the normal video
> ffmpeg tries to encode a very long output file (over 20 minutes, when I
> abort) even though the input files only have a duration of less than 15
> seconds in total. Therefore I thing it might be an issue with the framrerate
> (even tough I think both, the slideshow and the normal video have a
> framerate of 25 fps).

>     Stream #0:0: Video: h264 (High), yuv420p(progressive), 5184x3888, 25 fps, 25 tbr, 1k tbn, 50 tbc (default)
[...]
>     Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc

You can't mix these inputs using the concat demuxer:
https://trac.ffmpeg.org/wiki/Concatenate#demuxer
    All files must have the same streams (same codecs, same time base,
    etc.) but can be wrapped in different container formats.

The time bases are different (1k vs. 90k). There are options to adjust
them though, you might be able to fix your first slideshow command.

Also, you resolutions are different. This may or may not lead to
issues. But not this one perhaps. ;-)

Cheers,
Moritz