Convert M4V to AIFC — Free Online Tool

Convert M4V video files to AIFC audio format by extracting the AAC or MP3 audio track and re-encoding it to PCM big-endian audio — the native format used in Apple's professional audio ecosystem. This is ideal for pulling high-quality audio from iTunes video downloads or iOS-compatible content into a format suitable for audio editing workflows on macOS.

FFmpeg Command

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How It Works

M4V is a video container that typically holds H.264 or H.265 video alongside AAC audio. Since AIFC is a pure audio format, the video stream is discarded entirely during this conversion — no video re-encoding takes place. The AAC audio track extracted from the M4V is decoded and then re-encoded as 16-bit big-endian PCM (pcm_s16be), which is the default uncompressed codec for AIFC. This means the compressed, lossy AAC audio is being decoded to raw PCM, so while the resulting AIFC file will be much larger than the original audio track, it cannot recover any quality that AAC compression originally discarded. The output is a clean, uncompressed audio file in a format natively understood by macOS audio tools and professional DAWs like Logic Pro.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg program, the open-source multimedia processing engine that handles all decoding, stream selection, and re-encoding for this M4V-to-AIFC conversion.
-i input.m4v Specifies the input file — an M4V container that may hold H.264 or H.265 video alongside an AAC audio track. FFmpeg reads all streams from this file before deciding what to process.
-c:a pcm_s16be Sets the audio codec for the output to 16-bit signed big-endian PCM, which is the native uncompressed audio format for AIFC files. The AAC audio decoded from the M4V is re-encoded into this format, producing uncompressed audio suitable for professional macOS audio tools.
-b:a 128k Specifies a 128 kbps audio bitrate target, though for uncompressed PCM codecs like pcm_s16be this parameter has no practical effect — the actual bitrate is fixed by the bit depth (16-bit) and the source sample rate rather than a compression target. It is included here for command consistency but can be omitted without changing the output.
output.aifc Defines the output filename and triggers FFmpeg to use the AIFC container format. The .aifc extension tells FFmpeg to wrap the pcm_s16be audio stream in an AIFC (Audio Interchange File Format Compressed) container, which is Apple's extended version of AIFF that supports both compressed and uncompressed PCM audio. The video stream from the M4V is automatically dropped since AIFC is an audio-only format.

Common Use Cases

  • Importing the audio from an iTunes movie or TV episode download into Logic Pro or GarageBand for soundtrack analysis or remixing
  • Extracting dialogue or narration from an M4V educational video to use as source material in a professional audio editing session on macOS
  • Archiving the audio portion of an iOS-compatible M4V video in an uncompressed format for long-term preservation without further lossy compression
  • Preparing interview or lecture audio captured in M4V format for use in a broadcast production environment that requires big-endian PCM files
  • Converting the audio track of an Apple-formatted home video to AIFC for import into Final Cut Pro as a standalone audio clip
  • Stripping the audio from an M4V screencast or tutorial video to create a standalone audio guide compatible with professional macOS audio software

Frequently Asked Questions

No — converting from M4V to AIFC cannot improve audio quality beyond what was already in the M4V. The AAC audio in an M4V is a lossy format, meaning some audio data was permanently discarded when the M4V was originally created. Re-encoding that AAC to uncompressed PCM in AIFC simply gives you a lossless container for already-lossy audio. The benefit of AIFC is not improved quality but rather compatibility with professional audio tools and the elimination of any further lossy re-encoding in your workflow.
The M4V file stores its audio as compressed AAC, which can be 10–20 times smaller than uncompressed audio. AIFC with pcm_s16be stores every audio sample as raw 16-bit big-endian data with no compression. A 5-minute AAC track at 128k might be around 5MB, while the same audio as uncompressed PCM in AIFC will be roughly 50–100MB. This is expected behavior — the large file size is a hallmark of uncompressed, professional-grade audio formats.
No. AIFC does not support chapters, and it has very limited metadata capabilities compared to M4V. Chapter markers, iTunes metadata tags (like title, artist, or episode information), and multiple audio track information from the M4V will not be carried over to the AIFC output. Only the primary audio stream is extracted and converted. If metadata preservation is critical, you should store it separately before converting.
pcm_s16be stands for PCM (Pulse Code Modulation) signed 16-bit big-endian audio. The '16-bit' refers to the bit depth — the same as CD audio — and 'big-endian' refers to the byte order used by Apple's AIFC standard. For most uses, including Logic Pro and GarageBand imports, 16-bit AIFC is perfectly suitable. If you are working in a high-resolution audio production environment that requires 24-bit or 32-bit depth, you would need to modify the FFmpeg command to use pcm_s24be or pcm_s32be instead.
To change the PCM codec, replace 'pcm_s16be' in the command with another supported AIFC codec such as 'pcm_s24be' for 24-bit audio, 'pcm_s32be' for 32-bit integer, or 'pcm_alaw' for G.711 A-law compressed AIFC. For example: ffmpeg -i input.m4v -c:a pcm_s24be output.aifc. Note that for uncompressed PCM codecs like pcm_s16be and pcm_s24be, the -b:a (bitrate) flag has no meaningful effect since the bitrate is determined entirely by the bit depth and sample rate, not a compression setting.
Yes — on macOS or Linux you can use a shell loop to process multiple files at once. For example: for f in *.m4v; do ffmpeg -i "$f" -c:a pcm_s16be "${f%.m4v}.aifc"; done. This iterates over all M4V files in the current directory and produces a corresponding AIFC file for each one. On Windows, a similar batch loop can be written using a for loop in Command Prompt or PowerShell.

Technical Notes

M4V files may contain DRM protection applied by iTunes, in which case FFmpeg will not be able to read the audio stream and the conversion will fail — only DRM-free M4V files are compatible with this tool. The audio track in an M4V is almost always AAC encoded at 128k or 256k; FFmpeg fully decodes this to raw PCM before writing the AIFC output, so the conversion involves a full audio transcode rather than a stream copy. The output sample rate will match whatever was in the source M4V (typically 44100 Hz or 48000 Hz) unless you add an explicit -ar flag to the command to resample. AIFC files use big-endian byte ordering by design, which is a legacy of Motorola 68000-based Macintosh hardware — modern Apple Silicon and Intel Macs handle this transparently, but some non-Apple software may prefer AIFF with little-endian PCM instead. If your M4V contains multiple audio tracks (e.g., stereo and surround), FFmpeg will by default select the best-quality track; to extract a specific track, add -map 0:a:1 (or the relevant stream index) to the command.

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