ffmpeg -y 
ffmpeg -y -ss 159 -i a.mp4 -t 10 -an output.mp4
ffmpeg -i input_vid.mp4 -itsoffset 00:00:05.0 -i input_audio.wav -vcodec copy -acodec copy output.mp4  #delay voice for 5 seconds
src=8k-360x180_cube_lr
ffmpeg -y -i ${src}.jpg -filter:v "crop=in_w/4:in_h/3:0:0" -q:v 3 ${src}-1.jpg
ffmpeg -y -i ${src}.jpg -filter:v "crop=in_w/4:in_h/3:0:in_w/3" ${src}-2.jpg
ffmpeg -y -i ${src}.jpg -filter:v "crop=in_w/4:in_h/3:0:2*in_w/3" ${src}-3.jpg
ffmpeg -y -i ${src}.jpg -filter:v "crop=in_w/4:in_h/3:in_w/4:0" ${src}-4.jpg
ffmpeg -y -i ${src}.jpg -filter:v "crop=in_w/4:in_h/3:in_w/4:in_w/3" ${src}-5.jpg
ffmpeg -y -i ${src}.jpg -filter:v "crop=in_w/4:in_h/3:in_w/4:2*in_w/3" ${src}-6.jpg
 
ffmpeg -y -i va.mp4 -q:a 0 -map a va.mp3
 
ffmpeg -re -stream_loop -1 -i standard-360x180_cube_lr.mp4 -c copy -f flv rtmp://r730.kandao.tech/live/demo
ffmpeg -re -stream_loop -1 -i standard-360x180_cube_lr.mp4 -c copy -fflags +genpts -f flv output.mp4
get one frame from b.mp4
ffmpeg -i b.mp4 -vf fps=1 b-%04d.jpg
 
ffmpeg -f h246 -i a.h246 -vf fps=1 -y a.jpg
 
ffmpeg -f h246 -i a.h246 -y -f image2 -ss 0.8.010 -t 0.001 -s 352x240 a.jpg