Supported Audio & Video Formats

Overview

MP3 Toolbox supports a wide range of audio and video formats, allowing you to convert virtually any media file to MP3. Whether you have audio files in various formats or video files from which you want to extract audio, our tool handles them all with high-quality conversion.

Audio Formats

MP3 (MPEG Audio Layer III)

Status: Native format - no conversion needed
Extension: .mp3
Description: MP3 is the most popular audio format worldwide. If you upload an MP3 file, we'll read its existing metadata and allow you to edit tags and add cover art without re-encoding the audio, preserving the original quality.

Use cases: Editing metadata, adding cover art, fixing ID3 tags, organizing music library

M4A (MPEG-4 Audio)

Status: Converted to MP3
Extension: .m4a
Description: M4A is Apple's preferred audio format, commonly used in iTunes and Apple Music. It typically uses AAC (Advanced Audio Coding) compression. We convert M4A files to MP3 while preserving audio quality.

Codec: AAC (Advanced Audio Coding)
Use cases: Converting iTunes purchases, Apple Music files, iOS recordings

WAV (Waveform Audio File Format)

Status: Converted to MP3
Extension: .wav
Description: WAV is an uncompressed audio format that provides the highest quality but results in large file sizes. We convert WAV to MP3 with high-quality settings, significantly reducing file size while maintaining excellent audio fidelity.

Codec: PCM (Pulse Code Modulation)
Use cases: Converting studio recordings, professional audio files, CD rips

OGG (Ogg Vorbis)

Status: Converted to MP3
Extension: .ogg
Description: OGG is an open-source, patent-free audio format that uses Vorbis compression. It's popular among open-source enthusiasts and provides good quality at lower bitrates. We convert OGG files to MP3 for broader compatibility.

Codec: Vorbis
Use cases: Converting open-source audio files, Linux audio files, game audio

FLAC (Free Lossless Audio Codec)

Status: Converted to MP3
Extension: .flac
Description: FLAC is a lossless compression format that preserves original audio quality while reducing file size. It's popular among audiophiles. We convert FLAC to MP3, reducing file size significantly while maintaining high quality.

Codec: FLAC (lossless)
Use cases: Converting high-quality music collections, audiophile recordings, lossless archives

AAC (Advanced Audio Coding)

Status: Converted to MP3
Extension: .aac
Description: AAC is a high-quality audio codec used by Apple, YouTube, and many streaming services. It provides better quality than MP3 at similar bitrates. We convert AAC files to MP3 for universal compatibility.

Codec: AAC
Use cases: Converting streaming downloads, YouTube audio, modern audio files

WMA (Windows Media Audio)

Status: Converted to MP3
Extension: .wma
Description: WMA is Microsoft's proprietary audio format, commonly used in Windows Media Player. We convert WMA files to MP3, making them compatible with all devices and players.

Codec: Windows Media Audio
Use cases: Converting Windows Media Player files, legacy Windows audio files

Video Formats

MP4 (MPEG-4 Part 14)

Status: Audio extracted and converted to MP3
Extension: .mp4
Description: MP4 is the most common video format, used by YouTube, streaming services, and mobile devices. When you upload an MP4 file, we automatically extract the audio track and convert it to MP3, discarding the video component.

Video Codecs: H.264, H.265, VP9
Audio Codecs: AAC, MP3, AC-3
Use cases: Extracting audio from YouTube downloads, video podcasts, music videos, video recordings

MKV (Matroska Video)

Status: Audio extracted and converted to MP3
Extension: .mkv
Description: MKV is a flexible, open-source container format that can hold multiple audio, video, and subtitle tracks. We extract the primary audio track and convert it to MP3.

Video Codecs: H.264, H.265, VP8, VP9
Audio Codecs: AAC, MP3, FLAC, Vorbis, AC-3, DTS
Use cases: Extracting audio from high-quality video files, movie soundtracks, multi-track video files

Cover Art Formats

JPEG / JPG

Status: Supported
Extensions: .jpg, .jpeg
Description: JPEG is the most common image format for cover art. It provides good quality with reasonable file sizes. We accept JPEG images and embed them into your MP3 files.

Recommended size: 500x500px to 1000x1000px
Maximum size: 10MB

PNG

Status: Supported
Extension: .png
Description: PNG is a lossless image format that supports transparency. It's ideal for high-quality cover art. We embed PNG images directly into MP3 files.

Recommended size: 500x500px to 1000x1000px
Maximum size: 10MB

File Size Limits

Audio/Video Files: Maximum 100MB per file
Cover Art Images: Maximum 10MB per image

These limits ensure fast processing and prevent server overload. For larger files, consider:

• Compressing video files before upload
• Using audio extraction tools for very large video files
• Optimizing cover art images to reduce file size

Conversion Quality

All audio conversions use high-quality settings:

• Codec: libmp3lame (LAME MP3 encoder)
• Encoding: Variable Bitrate (VBR)
• Quality Level: 2 (high quality)
• Average Bitrate: 190-210 kbps
• Sample Rate: Preserved from source (typically 44.1kHz or 48kHz)
• Channels: Stereo or mono, depending on source

These settings provide excellent audio quality while maintaining reasonable file sizes. The VBR encoding adapts bitrate based on audio complexity, providing better quality for complex passages and smaller files for simpler audio.

Format Compatibility

Input Compatibility

We validate all uploaded files using multiple methods:

• File Extension: Whitelist of allowed extensions
• MIME Type: Content-Type header validation
• Magic Bytes: File signature verification to prevent spoofing

This multi-layer validation ensures security and prevents malicious file uploads.

Output Compatibility

All output MP3 files are:

• ID3v2.3 compliant: Maximum compatibility across all devices
• Standard MP3 format: Works with all MP3 players
• Cover art embedded: Displays correctly in all modern players
• Metadata complete: All tags properly formatted

Codec Information

Audio Codecs We Support (Input)

• MP3: MPEG Audio Layer III
• AAC: Advanced Audio Coding
• PCM: Pulse Code Modulation (uncompressed)
• Vorbis: Ogg Vorbis
• FLAC: Free Lossless Audio Codec
• WMA: Windows Media Audio
• AC-3: Dolby Digital (from video files)
• DTS: Digital Theater Systems (from video files)

Video Codecs We Handle (Input)

• H.264: AVC (Advanced Video Coding)
• H.265: HEVC (High Efficiency Video Coding)
• VP8/VP9: Google's video codecs

Note: Video codecs are only used to extract audio tracks. Video content is discarded.

Output Codec

MP3 (libmp3lame): All files are converted to MP3 using the LAME encoder, which is the industry standard for MP3 encoding. LAME provides excellent quality and universal compatibility.

Common Use Cases by Format

Converting iTunes/M4A Files

Many users convert M4A files purchased from iTunes or downloaded from Apple Music to MP3 for broader compatibility with non-Apple devices. Our tool handles this seamlessly, preserving audio quality and metadata.

Extracting Audio from Videos

Popular use cases include:

• Extracting music from music videos
• Creating audio versions of video podcasts
• Converting video recordings to audio files
• Creating ringtones from video clips

Organizing Music Libraries

Users often convert various formats to MP3 to standardize their music library:

• FLAC to MP3 for smaller file sizes
• WAV to MP3 for better portability
• OGG to MP3 for universal compatibility
• WMA to MP3 for cross-platform use

Format-Specific Tips

For Best Quality

• FLAC/WAV sources: Start with lossless formats for best results
• High bitrate sources: Higher input quality = better output
• Original recordings: Convert from original source when possible

For Smaller File Sizes

• VBR encoding: Our VBR setting automatically optimizes file size
• Mono sources: Mono audio results in smaller files
• Lower complexity: Simpler audio compresses better

For Maximum Compatibility

• MP3 output: Universal format supported everywhere
• ID3v2.3 tags: Maximum tag compatibility
• Standard sample rates: 44.1kHz works on all devices

Unsupported Formats

Currently, we do not support:

• WAV (compressed variants): Only standard PCM WAV is supported
• AIFF: Apple's uncompressed format (use WAV instead)
• DSD: Direct Stream Digital (use PCM conversion first)
• MIDI: Musical Instrument Digital Interface (not audio)
• Other video formats: Only MP4 and MKV are supported

If you need to convert unsupported formats, consider using a desktop tool first to convert to a supported format, then use MP3 Toolbox for final processing.

Technical Specifications

Supported Sample Rates

• 8 kHz
• 11.025 kHz
• 16 kHz
• 22.05 kHz
• 32 kHz
• 44.1 kHz (CD quality)
• 48 kHz (DVD quality)
• 96 kHz (high-resolution)

Supported Channel Configurations

• Mono (1 channel)
• Stereo (2 channels)
• Multi-channel (extracted as stereo)

Supported Bit Depths

• 8-bit
• 16-bit (CD quality)
• 24-bit (high-resolution)
• 32-bit (floating point)