> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getpatter.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Krisp Filter
> Proprietary Krisp VIVA noise / echo suppression as a Patter AudioFilter.
# Krisp VIVA Filter
`KrispVivaFilter` is a Patter `AudioFilter` backed by the [Krisp VIVA](https://krisp.ai/) noise- and echo-suppression SDK. It runs as a pre-STT filter in pipeline mode: caller PCM enters the filter, cleaned PCM exits and is forwarded to the STT provider.
Use it on noisy lines (call-centre, vehicle, café) where STT accuracy degrades because of background sound.
Krisp VIVA is a **proprietary SDK**. The Patter integration is open source and free, but you must obtain your own commercial licence from [krisp.ai](https://krisp.ai/) to use the underlying `krisp-audio` package and model files. Patter does not endorse, redistribute, or sublicense any Krisp software or models — it just calls the SDK on your behalf.
For an MIT-licensed alternative, see [DeepFilterNet](/python-sdk/providers/deepfilternet-filter).
## Install
The Krisp SDK ships outside PyPI's normal channels and requires a licence file:
```bash Python theme={null}
pip install "getpatter[krisp]" # installs krisp-audio>=2.0 + numpy
# Then set:
# KRISP_VIVA_SDK_LICENSE_KEY — provided by Krisp
# KRISP_VIVA_FILTER_MODEL_PATH — absolute path to your .kef model
```
```bash TypeScript theme={null}
# Krisp does not currently ship a TypeScript twin in the Patter SDK.
# Use DeepFilterNet for TS noise suppression in the meantime.
```
At time of writing the Patter TypeScript SDK does not include a Krisp filter — only Python. The TS pipeline can still use [`DeepFilterNetFilter`](/typescript-sdk/providers/deepfilternet-filter) for noise suppression.
## Constructor
```python Python theme={null}
from getpatter.providers.krisp_filter import KrispVivaFilter
from getpatter.providers.krisp_instance import KrispFrameDuration, KrispSampleRate
filt = KrispVivaFilter(
model_path=None, # falls back to KRISP_VIVA_FILTER_MODEL_PATH
noise_suppression_level=100, # 0..100, default 100
frame_duration_ms=KrispFrameDuration.MS_10, # 10 / 15 / 20 / 30 / 32
sample_rate=KrispSampleRate.HZ_16000, # initial; resized lazily if it changes mid-call
)
```
```typescript TypeScript theme={null}
// Not yet available in the TS SDK — see the warning above.
```
The filter raises:
* `RuntimeError` if `krisp-audio` is not installed or the licence key is missing.
* `ValueError` if `model_path` is missing or `frame_duration_ms` is unsupported.
* `FileNotFoundError` if the `.kef` model file does not exist.
## Usage in a pipeline agent
Plug it into `phone.agent(audio_filter=...)`:
```python Python theme={null}
import asyncio
from getpatter import Patter, Twilio, DeepgramSTT, AnthropicLLM, ElevenLabsTTS
from getpatter.providers.krisp_filter import KrispVivaFilter
phone = Patter(carrier=Twilio(), phone_number="+15550001234")
filt = KrispVivaFilter(noise_suppression_level=100)
agent = phone.agent(
stt=DeepgramSTT(),
llm=AnthropicLLM(),
tts=ElevenLabsTTS(voice_id="rachel"),
audio_filter=filt, # pre-STT noise suppression
system_prompt="You are a helpful assistant.",
)
asyncio.run(phone.serve(agent))
```
```typescript TypeScript theme={null}
// Use DeepFilterNetFilter on TS for now.
```
See the [`audio_filter` parameter on Agents](/python-sdk/agents) (pipeline mode only).
## Toggling at runtime
`KrispVivaFilter` exposes `enable()` / `disable()` so you can A/B-test the filter on a single call (e.g. when an operator presses a "raw audio" key):
```python theme={null}
filt.disable() # passthrough
filt.enable() # noise suppression on
filt.enabled = True
```
When disabled the filter returns the input PCM unchanged.
## When to use Krisp vs alternatives
| Use Krisp when… | Use [DeepFilterNet](/python-sdk/providers/deepfilternet-filter) when… | Skip filtering when… |
| -------------------------------------------------------------------------------------------- | --------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------ |
| You need best-in-class commercial-grade noise/echo suppression and you have a Krisp licence. | You want an MIT-licensed OSS alternative with no licence step. | The line is clean (typical broadband VoIP / mobile in quiet conditions) — the latency and CPU win is not worth it. |
## Notes
* The Krisp SDK is reference-counted via `KrispSDKManager`: multiple filter instances share one global init/destroy lifecycle, so you can hold one `KrispVivaFilter` per call without re-initialising the SDK each time.
* The filter expects the exact frame size: `sample_rate * frame_duration_ms / 1000` int16 samples per `process()` call. Patter's pipeline-mode audio bus already aligns to this.
* On any internal error the filter logs the failure and returns the **original** PCM unchanged so the call audio path is never broken — the VAD downstream will still receive audio even if Krisp temporarily fails.
## What's Next
The `audio_filter` parameter on `phone.agent(...)`.
OSS noise suppression alternative.
Voice activity detection downstream of the filter.
STT + LLM + TTS composition.