Finally did some more testing. Turns out that settings are largely irrelevant (for MKV concatenation that is).
It doesn't matter if attached video has different number of slices, references, b-frames, framerate... it will work well anyway.
The reason I was getting problems is because I was attaching an MKV produced by FFMPEG.
This command:
Code:
ffmpeg -loop 1 -i "image.png" -t 10.000 -vcodec libx264 -pix_fmt yuv420p -r 24 output.mkv
produces an MKV that's causing problems.
But if I do it like this:
Code:
ffmpeg -loop 1 -i "image.png" -t 10.000 -vcodec libx264 -pix_fmt yuv420p -r 24 output.h264
mkvmerge -o output.mkv output.h264
produced MKV is fine (even though MKVToolNix still complains).
What's going on here? Is FFMPEG's MKV muxing bugged?
I noticed that an MKV produced by FFMPEG loses "Frame Rate" and "Average Bitrate" information in Stream Summary->Stream Statistics in CodecVisa.