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This is a page from the Audivra documentation. Developer exports — index: http://127.0.0.1:3000/docs/llms.txt, full corpus: http://127.0.0.1:3000/docs/llms-full.txt, OpenAPI: http://127.0.0.1:3000/docs/openapi.json, Postman: http://127.0.0.1:3000/docs/postman.json. Press ⌘K to search docs.

Stream Opus TTS on low bandwidth

Deliver chunked Opus audio for mobile networks in the Global South — 48 kbps streams instead of multi-megabyte WAV files.

Developers

~10 min

Outcome: A streaming Opus pipeline your mobile app or IVR can play incrementally on 2G/3G links.

1
Why Opus instead of WAV
WAV responses from POST /api/v1/tts can be 500 KB+ for a short sentence — painful on M-Pesa-tier mobile data.
POST /api/v1/tts/stream returns chunked Opus (or AAC) optimized for Global South bandwidth. Typical footprint: ~48 kbps.
Use voice_id zuri-sw, umar-ha, or swara-hi for regional African languages on Kokoro-82M.

Request a streaming response

Set format to opus (default) or aac. The response uses Transfer-Encoding: chunked — read chunks as they arrive.

cURL — save stream

curl -X POST https://audivra.dev/api/v1/tts/stream \
  -H "Authorization: Bearer sk_live_…" \
  -H "Content-Type: application/json" \
  -d '{"text":"Habari. Karibu kwenye huduma yetu.","voice_id":"zuri-sw","format":"opus"}' \
  --output stream.opus

Play in the browser or mobile app

Opus chunks can be fed to MediaSource Extensions (web) or an Opus decoder on Android/iOS.

For quick validation, pipe to ffplay: ffplay -autoexit stream.opus

JavaScript — fetch stream

const res = await fetch("https://audivra.dev/api/v1/tts/stream", {
  method: "POST",
  headers: {
    Authorization: "Bearer sk_live_…",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    text: "Sentence one. Sentence two.",
    voice_id: "zuri-sw",
    format: "opus",
  }),
});

const reader = res.body?.getReader();
// Append chunks to MediaSource or buffer for native Opus decode

4
Tune for your network
Keep sentences under 500 characters for fast-path local routing (1 credit) when a local worker is configured.
Set DEFAULT_STREAM_FORMAT=opus in your deployment env for server-side defaults.
Monitor X-Characters and X-Stream-Format response headers for billing and debugging.
1 audio character = 1 credit. Streaming and sync TTS meter the same way.

Stream Opus TTS on low bandwidth

Why Opus instead of WAV

Request a streaming response

Play in the browser or mobile app

Tune for your network

Related reference

Text to speech API

Voices reference

Processing nodes