Convert AVI to M4A Online
Extract M4A audio from AVI files — classic movies, DivX, soundtracks. Free, in your browser.
.avi · up to 100 MB
What you can do
AVI to M4A: classic movies and DivX files into the Apple ecosystem
MP3 and AC-3 to AAC
MP3, AC-3, or PCM audio from AVI files converted to optimal AAC for Apple Music and iPhone.
DivX collection from the 2000s
Archive soundtracks from your DivX movie collection in Apple Music with complete metadata.
100% private
Your AVI file never leaves your device. FFmpeg.wasm processes everything locally in WebAssembly.
Home videos
Extract audio from family recordings in AVI to preserve them in Apple Music forever.
How it works
Three steps, no hassle
Upload your AVI file
Drag or select your .avi file — DivX movie, old camera video, DVD capture, or archive clip. Up to 500 MB, no signup.
Audio conversion to M4A
FFmpeg.wasm decodes AVI audio (MP3, AC-3, or PCM) and converts it to AAC in M4A container — the native format for Apple Music and iTunes.
Download your M4A file
Soundtrack ready for your Apple Music library, iPhone, or create a custom ringtone (.m4r).
FAQ
Got questions?
The AVI (Audio Video Interleave) container was developed by Microsoft in 1992 and has a radically different architecture from modern MPEG-4 containers. AVI uses the RIFF (Resource Interchange File Format) with interleaved blocks of audio and video data, without the hierarchical Box atom system used by MP4/M4A. The most common audio codecs in AVI are MP3 (codec ID 0x0055 in RIFF WAVE) and AC-3 (codec ID 0x2000), neither of which can do direct stream copy to the M4A container because M4A only accepts AAC in its standard specification.
This is the most important question for AVI to M4A conversion. Converting MP3 to AAC is a lossy-to-lossy transcode, generating a second generation of quality loss. Actual degradation depends on the original MP3 bitrate and the target AAC bitrate. MP3 at 128 kbps converted to AAC at 128 kbps — degradation is perceptible in controlled listening tests. MP3 at 192 kbps converted to AAC at 192 kbps — the difference is generally imperceptible for most listeners. Convertir.ai uses 192 kbps as the default bitrate, which is a good balance. For AVI with high-quality MP3 (256-320 kbps), conversion to AAC 256 kbps produces excellent results according to Hydrogenaudio benchmarks.
The AVI format with DivX or XviD video was the dominant movie distribution format on the internet from approximately 1999 to 2010. Many users have movie collections from that era in AVI format that no longer play easily on modern devices. Extracting M4A audio allows: (1) Archiving soundtracks of rare or hard-to-find films; (2) Creating a collection of 90s and 2000s movie soundtracks in Apple Music; (3) Extracting memorable dialogues to create iPhone ringtones (.m4r); (4) Recovering audio from home videos or family recordings archived in AVI from digitized analog cameras.
Yes, and it's the best possible case. Some AVI files, especially videos from old digital cameras (Canon PowerShot, Sony Cybershot from the 2000s) or video capture cards, contain uncompressed PCM audio (codec ID 0x0001 in RIFF WAVE for 16-bit linear PCM). When converting PCM to AAC, there is only one generation of loss — starting from a perfect source with no prior compression. The result with AAC at 256 kbps from PCM is practically indistinguishable from the original PCM according to Hydrogenaudio transparency standards.
The AVI container can contain virtually any audio codec that has a registered ID in the RIFF WAVE standard. The most common are: MP3 (MPEG-1 Layer III, 0x0055), uncompressed PCM/LPCM (0x0001), AC-3/Dolby Digital (0x2000), DTS (0x2001), MPEG-1 Layer II (0x0050), and less commonly ADPCM in Microsoft (0x0002) and IMA (0x0011) variants. The AC-3 codec is common in high-quality AVI movie files from the DivX era, as it allowed maintaining the original 5.1 surround audio from ripped DVDs.
Yes, perfectly. Compact digital cameras and miniDV camcorders from 2000-2010 (Canon, Sony, Panasonic, JVC) generated AVI files with PCM or MP3 audio at 44.1 kHz, 16-bit. Extracting audio from these home videos into M4A allows preserving them in Apple Music with metadata (date, event) without the bulky video content. Especially useful for preserving audio from family events, weddings, birthdays, school concerts, or any family event archived from digitized Mini-DV or Hi8 tapes.
Convert AVI to M4A: extract audio from DivX movies and classic videos for Apple Music
Converting AVI to M4A is the operation that connects two completely different eras of multimedia technology: the AVI format, developed by Microsoft in November 1992 as part of the Video for Windows package in Windows 3.1, and Apple's modern audio ecosystem based on M4A/AAC. The AVI (Audio Video Interleave) container uses the RIFF (Resource Interchange File Format) architecture, a binary block system inherited from Electronic Arts' IFF (Interchange File Format) standard of 1985, which interleaves audio data blocks ('01wb' in RIFF terminology for stream 1) and video ('00dc' for stream 0) in the file. This fixed interleave architecture was revolutionary in 1992 but has fundamental limitations: no native support for rich metadata, difficulty seeking in large files, and an AVI Index system that for files over 2 GB requires the OpenDML AVI 2.0 extension (specified in 1996). The most commonly used audio codecs in the historical AVI ecosystem are MP3 (the dominant codec in the DivX era, 1999-2010) and AC-3/Dolby Digital (used to preserve 5.1 surround audio from ripped DVDs). Neither of these codecs can perform direct stream copy to the M4A container, so conversion requires full decoding to PCM and re-encoding to AAC-LC, an operation that Convertir.ai runs entirely in the browser.
The historical and practical value of AVI to M4A conversion concentrates in two broad categories of files. The first is the DivX and XviD collection from 1999-2010: for over a decade, the AVI format with video encoded in DivX or XviD (both derived from the MPEG-4 Part 2 codec, developed by different open source community groups from the leaked Microsoft MPEG-4 v3 codec source of 1998) was the standard internet movie distribution format, first via Napster and early peer-to-peer networks, then through eMule, BitTorrent, and specialized forums. Cinema collections from that era include thousands of movies with soundtracks in MP3 at 128-320 kbps or AC-3 at 192-448 kbps that their owners want to archive in Apple Music or listen to on iPhone without importing the full video. The second category is digitized home video: analog camcorders (VHS, Hi8, Mini-DV) digitized via video capture cards in 2000-2015 generated AVI files with 16-bit PCM audio at 44.1 kHz representing irreplaceable family recordings — weddings, christenings, first steps, school concerts. Converting the audio from these files to M4A allows preserving them in Apple Music with date and event notes in metadata, freeing up video storage space while preserving the audio content that is frequently the most valuable part of the memory.
Convertir.ai runs AVI to M4A conversion entirely in the browser using FFmpeg.wasm. The process begins with validating the RIFF signature in the first 4 bytes of the file ('RIFF') and confirming the FourCC 'AVI ' in bytes 8-11 of the RIFF chunk. FFmpeg parses the 'hdrl' List (header list) containing the Stream Header ('strh') and Stream Format ('strf') for each stream: the audio stream has StreamType 'auds' in the strh, and the strf contains a WAVEFORMATEX with the codec ID that determines processing. For codec ID 0x0055 (MPEG-1 Layer III, MP3), FFmpeg uses libmp3lame for decoding. For 0x2000 (AC-3/Dolby Digital), it uses libdca. For 0x0001 (linear PCM), decoding is trivial — direct reading of 16-bit integer samples. The resulting PCM is processed through the libfdk_aac encoder or the native AAC encoder of libavcodec at 192 kbps by default. The output file is an MPEG-4 M4A container with ftyp major brand 'M4A ', a moov atom with duration and sample rate metadata, and AAC samples in the mdat atom. Since processing occurs entirely in local WebAssembly without data transmission to servers, content privacy is absolute — particularly relevant for family recordings, home videos, and personal material from past decades that the user does not want to leave their device.