ForceAlign

ForceAlign is a Python library for forced alignment of English text to English audio. It can generate word or phoneme-level alignments, identifying the specific time a word or phoneme was spoken within an audio recording. ForceAlign supports .mp3 and .wav audio file formats.

For phoneme-level alignments, ForceAlign currently supports the ARPABET phonetic transcription encoding.

ForceAlign uses PyTorch's Wav2Vec2 pretrained model for acoustic feature extraction and can run on both CPU and CUDA GPU devices. It now includes automatic speech-to-text transcription, making it even more flexible for use cases where transcripts are not readily available.

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Features

• Fast and accurate word and phoneme-level forced alignment of text to audio.
• Includes automatic speech transcription if a transcript is not provided.
• Optimized for both CPU and GPU.
• OS-independent—compatible with macOS, Windows, and Linux.
• Supports .mp3 and .wav audio file formats.

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Installation and Dependencies

1. Install ForceAlign:

   pip3 install forcealign

2. Install ffmpeg (required for audio processing):
   • macOS: brew install ffmpeg
   • Linux: sudo apt install ffmpeg
   • Windows: Install from ffmpeg.org

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Usage Examples

Example 1: Getting Word-Level Text Alignments with a Provided Transcript

from forcealign import ForceAlign

# Provide path to audio file and corresponding transcript
transcript = "The quick brown fox jumps over the lazy dog."
align = ForceAlign(audio_file='./speech.mp3', transcript=transcript)

# Run prediction and return alignment results
words = align.inference()

# Show predicted word-level alignments
for word in words:
    print(f"Word: {word.word}, Start: {word.time_start}s, End: {word.time_end}s")

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Example 2: Getting Word-Level Text Alignments with Automatic Speech Transcription

If a transcript is not provided, ForceAlign can automatically generate one using Wav2Vec2.

from forcealign import ForceAlign

# Provide path to audio file; omit transcript
align = ForceAlign(audio_file='./speech.mp3')

# Automatically generate transcript and align words
words = align.inference()

# Show the generated transcript
print("Generated Transcript:")
print(align.raw_text)

# Show predicted word-level alignments
for word in words:
    print(f"Word: {word.word}, Start: {word.time_start}s, End: {word.time_end}s")

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Example 3: Speech-to-Text Conversion

ForceAlign can be used as a standalone speech-to-text tool.

from forcealign import speech_to_text

# Generate transcript directly from an audio file
generated_transcript = speech_to_text("./speech.mp3")
print(generated_transcript)
# Output: "THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG"

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Example 4: Getting Phoneme-Level Text Alignments

from forcealign import ForceAlign

# Provide path to audio file and transcript
transcript = "The quick brown fox jumps over the lazy dog."
align = ForceAlign(audio_file='./speech.mp3', transcript=transcript)

# Run prediction and return alignment results
words = align.inference()

# Access predicted phoneme-level alignments
for word in words:
    print(f"Word: {word.word}")
    for phoneme in word.phonemes:
        print(f"Phoneme: {phoneme.phoneme}, Start: {phoneme.time_start}s, End: {phoneme.time_end}s")

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Example 5: Reviewing Word-Level Alignments in Real-Time

from forcealign import ForceAlign

# Provide path to audio file and transcript
transcript = "The quick brown fox jumps over the lazy dog."
align = ForceAlign(audio_file='./speech.mp3', transcript=transcript)

# Play the audio while printing word alignments in real-time
align.review_alignment()

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Use Cases

• Subtitle Generation:
  • Generate timestamps for subtitles or closed captions for videos.
• Phoneme Analysis:
  • Analyze phoneme-level details for language research, speech therapy, or pronunciation training.
• Animated Lip Syncing:
  • Use phoneme alignments to synchronize animated character lip movements with audio.
• Accessibility Tools:
  • Enhance accessibility by creating aligned captions or transcripts for audio recordings.

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FAQ

1. Does ForceAlign have speech-to-text capabilities?
Yes! If you do not provide a transcript, ForceAlign will automatically generate one using Wav2Vec2. You can also provide your own transcript for better accuracy.

2. Can ForceAlign be used with both CPU and GPU?
Yes. ForceAlign is optimized for both CPU and CUDA-enabled GPU devices. Using a GPU significantly speeds up processing for longer recordings.

3. Can ForceAlign handle non-English audio?
No. Currently, ForceAlign supports English only. Support for additional languages may be added in future updates.

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Acknowledgements

This project is heavily based upon a demo from PyTorch by Moto Hira: FORCED ALIGNMENT WITH WAV2VEC2.