ffmpeg 静音音频

Question

我有一个输出 4x mp4 的字符串。
我想在输出中添加安静的音频。
我试图插入 anullsrc=cl=mono:sample_rate=48000 但真的不知道在哪里插入它。它给了我一个错误。

ffmpeg -hwaccel_output_format cuda -i test.mxf -filter_complex "[0:v]yadif=1,format=yuv420p,split=4[vid1][vid2][vid3][vid4];[vid1]scale=-2:1080[1080];[vid2]scale=-2:432[432];[vid3]scale=-2:288[288];[vid4]scale=-2:216[216]" -map "[1080]" -map "[432]" -map "[288]" -map "[216]" -map 0:a:0 -c:v h264_nvenc -force_key_frames "expr:gte(t,n_forced*10)" -preset slow -rc vbr_hq -b:v:0 4.5M -b:v:1 1.5M -b:v:2 1.0M -b:v:3 0.5M -c:a aac -b:a 192k -f tee "[select=\'v:0,a\']1080.mp4|[select=\'v:1,a\']432.mp4|[select=\'v:2,a\']288.mp4|[select=\'v:3,a\']216.mp4"

Answer 1

您可以将 anullsrc 添加为 lavfi 输入，然后对其进行映射。
然后您必须添加 -shortest或添加 -t X其中 X 是视频的持续时间。ffmpeg -hwaccel_output_format cuda -i test.mxf -f lavfi -i "anullsrc=cl=mono:sample_rate=48000" -filter_complex "[0:v]yadif=1,format=yuv420p,split=4[vid1][vid2][vid3][vid4];[vid1]scale=-2:1080[1080];[vid2]scale=-2:432[432];[vid3]scale=-2:288[288];[vid4]scale=-2:216[216]" -map "[1080]" -map "[432]" -map "[288]" -map "[216]" -map 0:a:0? -map 1:a -c:v h264_nvenc -force_key_frames "expr:gte(t,n_forced*10)" -preset slow -rc vbr_hq -b:v:0 4.5M -b:v:1 1.5M -b:v:2 1.0M -b:v:3 0.5M -c:a aac -b:a 192k -shortest -f tee "[select=\'v:0,a\']1080.mp4|[select=\'v:1,a\']432.mp4|[select=\'v:2,a\']288.mp4|[select=\'v:3,a\']216.mp4"