The error I'm getting is in the title.

I want to merge the two audio streams from a video into one (yes, I've checked if there is two and there is). This is the command I'm using:

ffmpeg -i input.mp4 -filter_complex "[0:v]scale=-2:720,format=yuv420p[v];[0:a]amerge=inputs=2[a]" -map "[v]" -map "[a]" -c:v libx264 -crf 23 -preset medium -c:a aac -ar 44100 -ac 2 output.mp4

Any ideas why I could be getting the error?


Inside a filtergraph, each pad is associated with a single stream. And a specifier such as 0:a will match the first stream that qualifies. You need to specify two pads and fully specify the input streams.

  • Will this throw an error if only one input audio stream is inputted? I'm using it in a kind of automated program, and some videos may only have one audio stream, while others may have 2. – pigeonburger Nov 21 '20 at 6:34
  • No. of inputs should be equal to the inputs value of amerge. – Gyan Nov 21 '20 at 8:01

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