ffmpeg: -hls_time and -hls_init_time not working

Question

Source video: h264 mp4, 45 seconds, 30 fps, keyint 30, min keyint 16

I am trying to create an m3u8 playlist where the first chunk is smaller (2 seconds) and the rest are 10 seconds.

when using this command:

ffmpeg.exe -i test4_c.mp4 -codec copy -bsf:v h264_mp4toannexb -start_number 0 -hls_init_time 2 -hls_time 10 -f hls -hls_list_size 0 test4_hls.m3u8

result is 4 10 second ts chunks

when using this command:

ffmpeg.exe -i test4_c.mp4 -codec copy -bsf:v h264_mp4toannexb -start_number 0 -hls_init_time 2 -hls_time 10 -f hls -hls_list_size 100 test4_hls.m3u8

result is 23 2 second ts chunks

what's the issue here?

I have already read this: https://stackoverflow.com/questions/43489097/ffmpeg-hls-init-time-hls-time-not-working-together and it doesn't work

Answer 1

a colleague figured it out (for a 20 second input video):

ffmpeg -i input.mp4 -map 0 -c copy -f ssegment -segment_list playlist.m3u8 -segment_times 2,12,22 -break_non_keyframes 1 out%03d.ts

if used in a program then segment_times needs to be somehow generated with regards to media length - for instance it won't be 2,12,22 if your media is 60 seconds long and you want 20 second chunks (after the first 2 second one), it will be 2,22,42,62