How do I convert audio ffmpeg?
Re-encodes an audio file to another codec, or copies it when the codec already suits the target container.
Convert audio between formats
Re-encodes an audio file to another codec, or copies it when the codec already suits the target container.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vn -c:a libopus -b:a 96k -t 5 out.opus- Encode
- 105 ms
- Output
- 73.1 KB
- Cost
- $0.0016
- Result
- opus
job_4be4ab002ec54901
The part everyone gets wrong
Nominal bitrate is not delivered size. libopus defaults to variable bitrate, so -b:a is an average it aims for rather than a ceiling. In our own measurements Opus at 128k delivered 16% more bytes than the arithmetic predicted, which breaks storage estimates built on bitrate times duration.
Frequently asked questions
What goes wrong most often?
Nominal bitrate is not delivered size. libopus defaults to variable bitrate, so -b:a is an average it aims for rather than a ceiling. In our own measurements Opus at 128k delivered 16% more bytes than the arithmetic predicted, which breaks storage estimates built on bitrate times duration.
Do I need FFmpeg installed?
Not with Rendobar. The command on this page ran through the API against a URL, with no local FFmpeg and no server. The job id below it is the job that produced these numbers.
More recipes, all measured
Normalise audio loudness Brings perceived loudness to a standard target using the EBU R128 loudnorm filter. Mute part of a video's audio Silences a time range while leaving the rest of the audio and all of the video untouched. Convert MP4 to GIF with FFmpeg Turns a video into an animated GIF using a generated palette, which is the difference between a usable GIF and a muddy one. Extract audio from video with FFmpeg Pulls the audio track out of a video, copying it without re-encoding when the format allows.
Run this without installing FFmpeg
This exact command ran through the API against a URL.