Fact · Speech recognition
Azure's REST API for short audio requires the audio to be in one of the formats its page lists, which is a narrower set than the Speech SDK accepts.
Checked against its source on October 17, 2026
In the source's own words
“It must be in one of the formats in this table”
Speech to text REST API for short audio, Microsoft Learn (Azure AI Speech), n.d., Audio formats.
Open the original- What it measures
- The table lists WAV with PCM at 16 kHz, mono, and OGG with Opus, both at 16 kHz mono. Convert other files before you send them, or use the Speech SDK.
- What it does not show
- The page's formats table can change, so check it when you change the Content-type header.