whisper.cpp/examples/stream/README.md

stream

This is a naive example of performing real-time inference on audio from your microphone. The stream tool samples the audio every half a second and runs the transcription continously. More info is available in issue #10.

./stream -m ./models/ggml-base.en.bin -t 8 --step 500 --length 5000

https://user-images.githubusercontent.com/1991296/194935793-76afede7-cfa8-48d8-a80f-28ba83be7d09.mp4

Sliding window mode with VAD

Setting the --step argument to 0 enables the sliding window mode:

 ./stream -m ./models/ggml-small.en.bin -t 6 --step 0 --length 30000 -vth 0.6

In this mode, the tool will transcribe only after some speech activity is detected. A very basic VAD detector is used, but in theory a more sophisticated approach can be added. The -vth argument determines the VAD threshold - higher values will make it detect silence more often. It's best to tune it to the specific use case, but a value around 0.6 should be OK in general. When silence is detected, it will transcribe the last --length milliseconds of audio and output a transcription block that is suitable for parsing.

Building

The stream tool depends on SDL2 library to capture audio from the microphone. You can build it like this:

# Install SDL2 on Linux
sudo apt-get install libsdl2-dev

# Install SDL2 on Mac OS
brew install sdl2

make stream

Ensure you are at the root of the repo when running make stream. Not within the examples/stream dir as the libraries needed like common-sdl.h are located within examples. Attempting to compile within examples/steam means your compiler cannot find them and it gives an error it cannot find the file.

whisper.cpp/examples/stream$ make stream
g++     stream.cpp   -o stream
stream.cpp:6:10: fatal error: common/sdl.h: No such file or directory
    6 | #include "common/sdl.h"
      |          ^~~~~~~~~~~~~~
compilation terminated.
make: *** [<builtin>: stream] Error 1

Web version

This tool can also run in the browser: examples/stream.wasm