My purpose is to map multiple audios to one channel and trim them.
There is my ffmpeg command.
ffmpeg -framerate 30 -i test_%03d.png -ss 5 -t 20 -i s01.wav -ss 10 -t 30 -i s02.wav -filter_complex "[1]adelay=10000|10000,apad[a1]; [2]adelay=15000|15000[a2]; [a1][a2]amerge=2[a]" \ -map 0:v -map "[a]" -c:v libopenh264 -c:a mp3 test.mp4 It works perfectly when there are only two sound streams, if I want to map three sound streams it didn't trim them properly.
I think the reason is I set apad incorrectly.
Please tell me how to map and trim multiple streams in the same time.
With more streams(adelay might not the actually number I used in the command):
ffmpeg -framerate 30 -i test_%03d.png -i s01.wav -i s02.wav -i s03.wav -i s04.wav -filter_complex "[1]adelay=10000|10000,apad[a1]; [2]adelay=15000|15000,apad[a2]; [3]adelay=12000|15000,apad[a3]; [4]adelay=20000|10000[a4]; [a1][a2][a3][a4]amerge=4[a]" \ -map 0:v -map "[a]" -c:v libopenh264 -c:a mp3 test.mp4 
