This guide provides detailed information on NotebookLM’s supported audio file types for importing audio files as a source, including language compatibility, key considerations, and best practices for efficient transcription. At NotebookLM.in, we tested the compatibility, performance, and transcription accuracy of NotebookLM with various audio file types. The list provided is not exhaustive but reflects only the file types we could confirm as either working or not. All content on this page is verified for its accuracy as of 16 December 2024. NotebookLM can convert audio files from 130 languages. We will update the list after verifying. In the meantime, if you speak a language not listed here, please make a clear voice recording and upload it in one of the supported audio formats to your NotebookLM account and share the result in the comments.
Supported Audio File Types
NotebookLM supports the following audio formats:
| Format | Description |
|---|---|
| MP4 (.mp4) | Commonly used for video and audio, offering efficient compression. |
| M4A (.m4a) | Primarily on Apple devices, providing high-quality audio with efficient compression. |
| AIFF (.aiff) | An uncompressed format similar to WAV, used on Apple platforms. |
| AAC (.aac) | Advanced Audio Coding, known for high-quality audio at lower bitrates. |
| CAF (.caf) | Core Audio Format by Apple, supporting multiple codecs. |
| AMR (.amr) | Adaptive Multi-Rate, designed for speech coding in mobile devices. |
| WAV (.wav) | Waveform Audio File Format, uncompressed, preserving original audio quality. |
| MP3 (.mp3) | MPEG-1 Audio Layer III, balancing audio quality and file size. |
| Opus (.opus) | A versatile codec providing high-quality audio at low bitrates. |
Codecs
The codec used within these formats affects compatibility and transcription quality. Use standard codecs to maintain audio integrity:
- MP4: AAC for audio.
- M4A: AAC is preferred.
- AIFF: Typically uncompressed PCM.
- AAC: Standard implementations.
- CAF: AAC, ALAC, or uncompressed PCM.
- AMR: Standard AMR codec.
- WAV: Uncompressed PCM codecs.
- MP3: Standard MPEG-1 Layer III codecs.
- Opus: Ensure Opus is used within supported container formats.
Best Practices for Recording Source Audio for NotebookLM
Files must contain clear speech. Files with significant ambient noise, overlapping voices, or multiple individuals speaking simultaneously without distinguishable speech are not transcribed, although this functionality may improve in the near future. Best practices include recording in a quiet environment, using high-quality microphones, minimising background noise, avoiding interruptions, and ensuring that only one person speaks at a time.
Unsupported Audio File Types
NotebookLM does not support the following formats:
- FLAC (.flac): Lossless format preserving original audio quality.
- OGG (.ogg): Open-source container supporting various codecs. Google might add this as a supported format.
- FAP (.fap): Less common audio format.
- MP2 (.mp2): Older MPEG-1 Audio Layer II format.
- WebM (.webm): Primarily a video container supporting codecs like Opus.
- WMA (.wma): Developed by Microsoft, not supported by NotebookLM.
Convert these to supported formats (M4A, MP4, WAV, MP3) using reliable audio conversion tools before importing.
Common Voice Recording Applications and Supported Formats
Different devices and applications use various formats for voice recordings. The table below summarises common applications and their compatibility with NotebookLM:
| Voice Recording App | Default Audio Format | Supported by NotebookLM | Notes |
|---|---|---|---|
| iPhone Voice Memos | M4A (.m4a), CAF (.caf) | ✔️ M4A, ✔️ CAF | Ensure CAF files use AAC codec. |
| Android Voice Recorder | AMR (.amr), AAC (.m4a), WAV (.wav) | ✔️ AMR, ✔️ AAC, ✔️ M4A, ✔️ WAV | Supports multiple formats. |
| Sony Voice Recorder | AMR (.amr), WAV (.wav) | ✔️ AMR, ✔️ WAV | Both formats are supported. |
| Samsung Voice Recorder | M4A (.m4a), AMR (.amr) | ✔️ M4A, ✔️ AMR | Compatible with NotebookLM. |
| Easy Voice Recorder (Android) | M4A (.m4a), MP3 (.mp3) | ✔️ M4A, ✔️ MP3 | Ensure MP3 files use standard codecs. |
| ASR Voice Recorder (Android) | M4A (.m4a), MP3 (.mp3), WAV (.wav) | ✔️ M4A, ✔️ MP3, ✔️ WAV | FLAC is unsupported. |
| RecForge II (Android) | AMR (.amr), M4A (.m4a), OGG (.ogg), MP3 (.mp3), FLAC (.flac), WAV (.wav) | ✔️ AMR, ✔️ M4A, ✔️ MP3, ✔️ WAV | OGG and FLAC require conversion. |
| Voice Recorder by Splend Apps (Android) | MP3 (.mp3), M4A (.m4a), WAV (.wav) | ✔️ MP3, ✔️ M4A, ✔️ WAV | Supports multiple formats. |
| Google Voice Recorder | WebM (.webm), Opus codec | ✔️ Opus, ❌ WebM | Opus codec is supported; WebM is not. |
Importing a Local Audio File
- Log in to NotebookLM: Access your NotebookLM account and open the desired notebook.
- Initiate Import: Select the option to import a local audio file.
- Select File: Choose an audio file in a supported format (e.g., M4A, MP4, WAV, AMR, MP3).
- Transcription: NotebookLM will automatically transcribe the audio and add the text to your notebook.
- Review: Check the transcription for accuracy and make necessary corrections.
Language Support
NotebookLM supports a wide range of spoken languages, all of which are listed and discussed in a dedicated article that can be found at NotebookLM Supported Languages for Audio Input Sources
Audio Quality
High-quality recordings improve transcription accuracy. Record in quiet environments, use quality microphones, and ensure clear speech.
Creating Custom Sample Audio Files
Using Recording Software
Audacity is a free, open-source tool for recording and editing audio files.
- Download Audacity: Visit Audacity Official Site.
- Record Audio: Launch Audacity, click the Record button, and speak clearly.
- Edit: Trim or enhance the audio as needed.
- Export: Go to File > Export > Export as [Format] (e.g., M4A, WAV, MP3). Choose the format and save the file.
Converting Existing Audio Files
Use reliable audio conversion tools to convert unsupported formats to supported ones.
- Online Audio Converters:
- Online Audio Converter:
- Visit the website.
- Upload your audio file.
- Select the target format (e.g., M4A, MP3).
- Adjust quality settings if necessary.
- Convert and download the file.
- Zamzar Audio Converter:
- Navigate to the website.
- Upload your audio file.
- Choose the desired output format.
- Click “Convert Now” and download the converted file.
- Online Audio Converter:
- Desktop Audio Converters:
- Freemake Audio Converter:
- Download and install the software.
- Add your audio files.
- Select the output format and codec.
- Convert the files.
- Format Factory:
- Download and install Format Factory.
- Open the application and select the “Audio” section.
- Add your audio files.
- Choose the output format and codec.
- Start the conversion process.
- Freemake Audio Converter:
Important Tip on Codecs
Choose standard codecs like AAC for M4A or MP3 for broader compatibility. Maintain consistent bitrate and sampling rates to preserve audio quality. Test converted files by playing them to ensure integrity before importing into NotebookLM.
Ensuring Quality and Compatibility
Audio Quality Tips
- Clear Speech: Ensure the speaker’s voice is clear and distinct.
- Consistent Volume: Maintain uniform audio levels throughout the recording.
- Standard Pronunciation: Use standard language pronunciation to enhance transcription accuracy.
- Appropriate Codec Selection: Choose widely supported codecs to maintain audio integrity.
Verifying File Formats and Codecs
- Use Media Players: Verify audio file integrity with tools like VLC Media Player.
- Check File Extensions: Ensure correct file extensions (e.g., .mp3, .wav).
- Metadata Inspection: Use MediaInfo to view codec and format information.
- Test Playback: Play the audio file after conversion to confirm functionality before importing.
Additional Resources and Tools
Speech Synthesis Tools
- Google Text-to-Speech: Converts text into natural-sounding speech in multiple languages.
- Amazon Polly: Offers text-to-speech services with various voices and languages.
GitHub Repositories
- Awesome Public Datasets: A curated list of public datasets, including those for speech and audio.
Conclusion
NotebookLM supports various audio formats, including MP4, M4A, AIFF, AAC, CAF, AMR, WAV, MP3, and Opus. Unsupported formats such as FLAC, OGG, FAP, MP2, WebM, and WMA must be converted before importing. High-quality recordings and standard codecs ensure accurate transcriptions.
For further assistance, refer to NotebookLM’s official support channels.
