Audio Bitrate

Sets the output audio bitrate for lossy formats.

video-audio-bitrate accepts a bitrate string with a k suffix representing kilobits per second. The value is applied to the encoded audio stream in the output, whether the output is a muxed video file (fm=mp4, fm=hls, fm=dash) or a lossy audio-only file (fm=m4a, fm=mp3).

https://assets.imgix.net/videos/girl-reading-book-in-library.mp4?fm=mp4&video-audio-bitrate=128k

Common values are 96k, 128k, 192k, and 320k. Higher bitrates preserve more audio detail at the cost of larger file size. For speech-dominant content, 96k or 128k is typically sufficient. For music or high-fidelity audio, 192k or higher is recommended.

The default bitrate is 192k. This parameter is ignored for fm=wav, which uses lossless PCM encoding and has no bitrate setting.

See Audio-Only Output for extracting audio without video.