FFmpeg converting two videos with dynamic frame rates - dup/drop frames

Question

I have problems with converting two videos using ffmpeg. Those videos have dynamic frame rate. I'm using this ffmpeg command:

ffmpeg -y -i /storage/emulated/0/Movies/RMR/RMR_camera_2017-10-04-20-42-56.mp4 -i /storage/emulated/0/Movies/RMR/RMR_screen_2017-10-04-20-42-56.mp4 -strict experimental -preset ultrafast -filter_complex [0]scale=iw/4:ih/4[pip];[pip]transpose=2[rotate];[1][rotate]overlay=main_w-overlay_w-30:main_h-overlay_h-10 -profile:v main -level 3.1 -ar 44100 -b:a 160k -crf 20 -s 720x1280 -vcodec h264 -vsync 2 -acodec aac -movflags +faststart /storage/emulated/0/Movies/RMR/out.mp4

I'm using -vsync to drop duplicated frames. This is not good enough, video is with freezing frames. How can I prevent freezing?

Answer 1

为两者设置恒定的帧速率
ffmpeg -i ... -i ... -lavfi '[0:v]fps=24000/1001[v1];[1:v]fps=24000/1001[v2];other_filters...' ...