Script to transcribe audio or video file using whisper.cpp

run-whisper.sh

#!/bin/bash

FFMPEG="./ffmpeg"
WHISPER="./whisper-cli"

# Function to display usage instructions
usage() {
    echo "Usage: $0 <input-file>"
    exit 1
}

# Check if the user provided an argument
if [ $# -eq 0 ]; then
    echo "Error: No input file provided."
    usage
fi

# Get the input file
INPUT_FILE="$1"

# Check if the file exists
if [ ! -f "$INPUT_FILE" ]; then
    echo "Error: File '$INPUT_FILE' does not exist."
    exit 1
fi

# Check if ffmpeg is installed
if ! command -v "${FFMPEG}" &> /dev/null; then
    echo "Error: ffmpeg is not installed. Please install it to use this script."
    exit 1
fi


# Check if the models folder exists, and the required model file is available
MODEL_DIR="models"
MODEL_FILE="$MODEL_DIR/ggml-small.en.bin"
MODEL_DOWNLOAD_SCRIPT="$MODEL_DIR/download-ggml-model.sh"
MODEL_DOWNLOAD_URL="https://raw.githubusercontent.com/ggerganov/whisper.cpp/refs/heads/master/models/download-ggml-model.sh"

if [ ! -d "$MODEL_DIR" ] || [ ! -f "$MODEL_FILE" ]; then
    echo "Models folder or required model file not found."
    echo "Setting up the models folder and downloading the required model..."

    # Create the models folder if it doesn't exist
    mkdir -p "$MODEL_DIR"

    # Download the model download script
    echo "Downloading the model download script..."
    curl -o "$MODEL_DOWNLOAD_SCRIPT" "$MODEL_DOWNLOAD_URL"

    # Make the script executable
    chmod +x "$MODEL_DOWNLOAD_SCRIPT"

    # Run the script to download the small.en model
    echo "Downloading the small.en model..."
    "$MODEL_DOWNLOAD_SCRIPT" small.en

    # Check if the model was successfully downloaded
    if [ ! -f "$MODEL_FILE" ]; then
        echo "Error: Failed to download the model file."
        exit 1
    fi

    echo "Model setup completed successfully."
fi


# Extract the file extension
EXT="${INPUT_FILE##*.}"
FILENAME="${INPUT_FILE%.*}"
OUTPUT_FILE="${FILENAME}.wav"

# Check if the input file is a valid format
if ! "${FFMPEG}" -v error -i "$INPUT_FILE" -f null - &> /dev/null; then
    echo "Error: Invalid input file format."
    exit 1
fi

# Check if the file is already a .wav
if [ "$EXT" != "wav" ]; then
    # Convert to .wav with specified arguments
    echo "Converting '$INPUT_FILE' to '$OUTPUT_FILE'..."
    "${FFMPEG}" -i "$INPUT_FILE" -ar 16000 -ac 1 -c:a pcm_s16le "$OUTPUT_FILE"

    # Check if the conversion was successful
    if [ $? -eq 0 ]; then
        echo "Conversion successful! Output file: '$OUTPUT_FILE'"
    else
        echo "Error: Conversion failed."
        exit 1
    fi
fi

"${WHISPER}" -t 6 -m "${MODEL_FILE}" -osrt -f "${OUTPUT_FILE}"
echo "Transcribed subtitled are in ${OUTPUT_FILE}.srt"
if [ "$EXT" != "wav" ]; then
    echo "Deleting temporary wav file"
    rm -f "${OUTPUT_FILE}"
fi