Good day.
First, your mp4 file should not contain B-frames. This can be checked with ffprobe, for example
Code:
ffprobe -show_frames file.mp4 > report.txt
If the report file contains
then you should re-encode mp4 file to play it smoothly.
WCS does not support B-frames in any stream published. See also VOD
known issues.
Also, your channel bandwith should allow to play the stream from mp4 file, otherwise it can be played unsmoothly. For example, if you try to play 1080p file with bitrate 10 Mbps, your channel between WCS and playing browser should be good enough for the stream to pass. You can test the channel using iperf as described
here.