Extract Audio from Y4M to AIFC — Free Online Tool
Extract audio from a Y4M (YUV4MPEG2) video file and save it as an AIFC file using the PCM 16-bit big-endian codec — ideal for lossless intermediate workflows where audio needs to be separated from raw uncompressed video. AIFC preserves professional-grade audio fidelity in a format widely supported by Apple and broadcast tools.
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FFmpeg Command
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Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
Y4M files store raw, uncompressed video frames (rawvideo codec) and may carry an audio stream alongside them. This tool discards the video stream entirely using FFmpeg's -vn flag, then extracts the audio and encodes it into AIFC format using the PCM signed 16-bit big-endian codec (pcm_s16be). Because AIFC's default PCM codec is lossless and uncompressed in its PCM form, the audio data is transcoded into a structured big-endian PCM container rather than simply copied — the result is a standalone AIFC audio file with no video data. No re-encoding of visual content occurs since the video is simply dropped.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, which is running here as FFmpeg.wasm compiled to WebAssembly and executing entirely within your browser — no files leave your device. |
-i input.y4m
|
Specifies the input file in Y4M (YUV4MPEG2) format — a raw, uncompressed video file that may contain both rawvideo frames and an audio stream to be extracted. |
-vn
|
Disables video output entirely, instructing FFmpeg to ignore and discard the rawvideo stream from the Y4M file so that only the audio track is passed to the output AIFC file. |
-c:a pcm_s16be
|
Encodes the extracted audio using the PCM signed 16-bit big-endian codec, which is the standard lossless PCM format for AIFC and AIFF containers and is natively compatible with Apple and professional broadcast tools. |
-b:a 128k
|
Sets a target audio bitrate of 128 kbps; for uncompressed PCM codecs like pcm_s16be this has no practical effect since the bitrate is fixed by sample rate and bit depth, but it is included as a default parameter that becomes relevant if a compressed AIFC codec such as pcm_alaw or pcm_mulaw is substituted. |
output.aifc
|
Specifies the output file in AIFC format — the .aifc extension tells FFmpeg to use the AIFC container, which wraps the extracted PCM audio in Apple's extended AIFF structure supporting both uncompressed and compressed audio codecs. |
Common Use Cases
- Separating a narration or dialogue track from a Y4M intermediate file produced by a lossless video editing pipeline for further audio post-production in a DAW like Logic Pro or Pro Tools.
- Extracting reference audio from a Y4M file used as an intermediate format between video processing tools (e.g., output of Avisynth or VapourSynth) where only the audio is needed for review or synchronization.
- Archiving the audio component of a raw Y4M capture independently in AIFC format, which is compatible with Apple Final Cut Pro and other professional macOS-based audio tools.
- Converting a Y4M file's audio into AIFC for delivery to broadcast workflows or post-production facilities that require big-endian PCM audio in the AIFC/AIFF family of formats.
- Isolating audio from a Y4M test file generated during codec development or video quality analysis pipelines, where the audio track needs to be checked or processed separately.
- Producing a standalone AIFC audio file from a Y4M source as part of an automated transcoding pipeline that feeds audio into Apple-ecosystem applications.
Frequently Asked Questions
Y4M (YUV4MPEG2) is primarily a raw video format designed for lossless video piping between applications, and audio support in Y4M files is rare and not standardized across all tools. If your Y4M file has no audio stream, FFmpeg will produce an empty or invalid AIFC file. Before using this tool, you can confirm your Y4M file contains audio by inspecting it with FFprobe or a media info tool — if no audio stream is reported, extraction will fail.
If the source audio in your Y4M file is already 16-bit PCM, encoding to AIFC with pcm_s16be is effectively lossless — no audio quality is lost. However, if the source audio has a higher bit depth (such as 24-bit or 32-bit), converting to pcm_s16be will reduce the bit depth and introduce quantization, which is a subtle but measurable form of quality reduction. In that case, you may want to modify the FFmpeg command to use pcm_s24be or pcm_s32be instead to preserve the original bit depth in the AIFC output.
Yes — AIFC supports several PCM codecs beyond pcm_s16be, including pcm_s24be (24-bit), pcm_s32be (32-bit), pcm_f32be (32-bit float), and pcm_f64be (64-bit float). To change the bit depth, replace '-c:a pcm_s16be' in the command with your preferred codec, for example: 'ffmpeg -i input.y4m -vn -c:a pcm_s24be output.aifc'. The '-b:a 128k' bitrate flag is primarily relevant for compressed codecs like pcm_alaw or pcm_mulaw and has little effect on uncompressed PCM variants, so you may also omit it when using lossless PCM codecs.
AIFC (and its parent format AIFF) were developed by Apple at a time when Apple hardware used Motorola 68000 processors, which are big-endian architectures — meaning the most significant byte of a multi-byte value is stored first. This big-endian byte order is baked into the AIFC specification for its PCM codecs (pcm_s16be, pcm_s24be, etc.), which is why they differ from WAV's little-endian PCM. Modern Apple software and broadcast tools handle this transparently, so the byte order rarely causes practical issues when working in Apple or professional audio ecosystems.
Y4M files carry very minimal metadata — essentially just video parameters like frame rate, frame size, and color space encoded in the file header. There is no standardized metadata tagging (such as title, artist, or track info) in the Y4M format. As a result, the AIFC output file will generally contain no meaningful metadata tags, since there is nothing to transfer from the source. If you need to embed metadata in the AIFC file, you would need to add it separately using an audio tagging tool after extraction.
You can batch process multiple Y4M files using a shell loop around the FFmpeg command. On Linux or macOS, run: 'for f in *.y4m; do ffmpeg -i "$f" -vn -c:a pcm_s16be -b:a 128k "${f%.y4m}.aifc"; done'. On Windows Command Prompt, use: 'for %f in (*.y4m) do ffmpeg -i "%f" -vn -c:a pcm_s16be -b:a 128k "%~nf.aifc"'. This is particularly useful when working with a series of Y4M intermediate files from a video processing pipeline where you need to isolate the audio from each file.
Technical Notes
Y4M is a headerless, uncompressed video container used almost exclusively as an intermediate or piping format — for example, passing raw frames between VapourSynth, x264, or FFmpeg instances. Because it stores rawvideo frames, Y4M files can be extremely large even for short clips, and audio tracks within Y4M are uncommon and not universally supported by all tools that read the format. AIFC, as an extension of Apple's AIFF format, natively supports big-endian PCM audio at multiple bit depths as well as compressed codecs like G.711 A-law (pcm_alaw) and μ-law (pcm_mulaw). The default codec used here, pcm_s16be, produces uncompressed 16-bit signed big-endian PCM audio, which is lossless at 16-bit depth and directly compatible with Apple Final Cut Pro, Logic Pro, and professional broadcast ingestion systems. The AIFC container does not support video, subtitles, chapters, or multiple audio tracks, making it purely an audio delivery format. One known limitation is that the -b:a bitrate flag has no meaningful effect on uncompressed PCM codecs like pcm_s16be — the actual bitrate is determined entirely by the sample rate and bit depth of the audio stream.