I am trying to convert mp3 audio files on the fly with ffmpeg since pifm(a program to transmit over the FM band) only takes a specific file. I was told I could use:

ffmpeg -i input.mp3 -f s16le -ar 22.05k -ac 1 - | sudo ./pifm - 

But ffmpeg returns an error saying that I must select at least one output source. How can I fix this to recognize that it is supposed to pipe it to the pifm program?

1 Answer 1


The documentation said your syntax should be;

ffmpeg -i input.mp3 -f s16le -ar 22.05k -ac 1 pipe:1 | sudo ./pifm -

- is common and pipe:1 is not, but that's what it supports.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.