Streamline my local transcription command for Raycast

Disclaimer: This content reflects my personal opinions, not those of any organizations I am or have been affiliated with. Code samples are provided for illustration purposes only, use with caution and test thoroughly before deployment.

In my previous blog, I asked Raycast to create an iTerm2 terminal to run the transcription script. This was because I needed to press CTRL+C to stop the sox recording. However, I found that launching iTerm2 and zsh took a significant amount of time, sometimes up to 5 to 10 seconds, which was too slow for quickly jotting down thoughts.

To address this issue, I discovered a way to stop the sox recording without opening the iTerm terminal. Instead of using CTRL+C, I can send a kill signal to the sox process. To achieve this, I utilize some shell script tricks to save the PID (Process ID) of sox and display a macOS pop-up. When I press the pop-up button, it sends a kill signal to the sox process, effectively stopping the recording.

Here’s the updated code:

#!/bin/bash

# Required parameters:
# @raycast.schemaVersion 1
# @raycast.title Transcribe
# @raycast.mode silent

# Optional parameters:
# @raycast.icon 💬

# Documentation:
# @raycast.description Transcribe with local model
# @raycast.author Shing Lyu
# @raycast.authorURL https://shinglyu.com

WHISPER_CPP_PATH=/Users/shinglyu/whisper.cpp
MODEL=models/ggml-small.bin
RECORDING_PATH="${TMPDIR}/transcribe/"
RECORDING_FILE="${RECORDING_PATH}/recording-$(date +%s).wav"
TRANSCRIPTION_FILE="${RECORDING_FILE}.txt"

mkdir $RECORDING_PATH
echo "Press Ctrl-C to stop the recording"
sox -t coreaudio "MacBook Pro Microphone" -r 16000 -c 1 -b 16 "${RECORDING_FILE}" &
pid=$!

# Display a confirmation popup
osascript -e 'tell app "System Events" to display dialog "Press Stop to stop recording" buttons {"Stop"} default button "Stop" with icon caution'

# If the user clicks "Stop", kill the sox process
if [ "$?" -eq 0 ]; then
    kill "$pid"
fi

cd "${WHISPER_CPP_PATH}"
./main -m "${MODEL}" -f "${RECORDING_FILE}" -otxt "${TRANSCRIPTION_FILE}" --language auto

clear
echo "Transcription:"
echo "--------------"
cat "${TRANSCRIPTION_FILE}" | sed 's/^[ \t]*//g' | tr '\n' ' ' | sed 's/  */ /g' | tee pbcopy
echo ""
echo "--------------"

# copy the file content to clipboard
cat "${TRANSCRIPTION_FILE}" | sed 's/^[ \t]*//g' | tr '\n' ' ' | sed 's/  */ /g' | pbcopy
echo "Copied to clipboard"
osascript -e "display notification \"$message\" with title \"Transcription finished\""

The key part of this code is the following section:

sox -t coreaudio "MacBook Pro Microphone" -r 16000 -c 1 -b 16 "${RECORDING_FILE}" &
pid=$!

# Display a confirmation popup
osascript -e 'tell app "System Events" to display dialog "Press Stop to stop recording" buttons {"Stop"} default button "Stop" with icon caution'

# If the user clicks "Stop", kill the sox process
if [ "$?" -eq 0 ]; then
    kill "$pid"
fi

This code displays a macOS confirmation pop-up with a “Stop” button. If the user clicks the “Stop” button, it sends a kill signal to the sox process, effectively stopping the recording.

Since we no longer need to open iTerm, we don’t require a wrapper AppleScript. This approach allows for a faster and more streamlined transcription process from Raycast. Now the recording starts almost instantaneously after triggering from Raycast.

TMPDIR is a special directory on MacOS that serves as a designated location for storing temporary files. Additionally, I changed the output directory to this TMPDIR, ensuring that the recorded audio file will be automatically cleaned up after the transcription process is complete. This helps in maintaining a tidy system by preventing the accumulation of unnecessary files.

Bonus: Opening Bedrock Chat

Since I frequently use Amazon Bedrock’s chat through the AWS console, I added a parameter to the script that allows me to immediately open the Bedrock Chat URL. This way, I can either paste what I just said into the chat or type a prompt and then paste my transcription.

# if $1 is set to `--open-bedrock-chat`, open the URL https://eu-central-1.console.aws.amazon.com/bedrock/home?region=eu-central-1#/chat-playground?modelId=anthropic.claude-3-sonnet-20240229-v1%3A0
if [ "$1" = "--open-bedrock-chat" ]; then
    open "https://eu-central-1.console.aws.amazon.com/bedrock/home?region=eu-central-1#/chat-playground?modelId=anthropic.claude-3-sonnet-20240229-v1%3A0"
    echo "Opened Bedrock Chat"
fi

Bonus 2 : Improving zsh Startup

Before implementing the above solution, I tried to speed up the zsh startup. While I did manage to make zsh launch faster, it was still not fast enough. But it might be useful for you. Here’s how I approached it:

1. Profiling zsh launch

   To profile the launch time of zsh, I added the following lines to the beginning and end of my ~/.zshrc file:

   
   zmodload zsh/zprof
   
   # main content of zshrc
   
   zprof
   
   

   This allowed me to identify the parts of the configuration that were taking the most time. Tuns out that loading nvm (a Node.js version manager) takes a lot of time.

2. Lazy loading nvm (Node Version Manager)

   I used the zsh-nvm plugin to lazy load nvm (Node Version Manager) in zsh. Here’s how to set it up with Oh My Zsh:

   • Clone the repository: git clone https://github.com/lukechilds/zsh-nvm ~/.oh-my-zsh/custom/plugins/zsh-nvm

   • Add the plugin to your ~/.zshrc file: plugins+=(zsh-nvm)

   • Add the lazy loading configuration before the plugin line: export NVM_LAZY_LOAD=true

3. Speed up iTerm2 launch by avoiding ASL log loading

   To speed up iTerm2 launch time, set the custom command to /bin/zsh -il in the profile. This bypasses searching the system ASL logs (reference: macos - iTerm/Terminal OS X slow in opening a shell - Super User).

While these steps helped improve the zsh startup time, it was still not fast enough for my needs. The updated Whisper.cpp transcription script with the macOS pop-up approach proved to be a more efficient solution.