Extract Audio from Y4M to OGA — Free Online Tool
Extract audio from a Y4M (YUV4MPEG2) video file and save it as an OGA file using the Vorbis codec. Since Y4M is a raw, uncompressed intermediate format often used in video processing pipelines, this tool is especially useful for pulling audio out of lossless capture or transcoding workflows and packaging it into a compact, open-standard Ogg Vorbis file.
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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 with no video encoding at all — they are essentially a sequence of YUV pixel data with a simple header. When audio is present in a Y4M file, it is also typically uncompressed or lightly encoded. This tool discards the raw video stream entirely and encodes the audio into Vorbis format, wrapping it in an OGA container (an audio-only variant of the Ogg container). The Vorbis encoder uses variable bitrate (VBR) encoding controlled by a quality scale, so the output is a lossy but perceptually efficient audio file. No video data survives in the output — OGA supports only audio streams, making it a clean audio-extraction result.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary. In the browser version of this tool, this runs as FFmpeg.wasm compiled to WebAssembly — no installation required and no files leave your device. |
-i input.y4m
|
Specifies the input file in Y4M (YUV4MPEG2) format. FFmpeg reads the raw uncompressed video frames and any audio stream present in the Y4M container. |
-vn
|
Disables video output entirely, telling FFmpeg to ignore the raw YUV video stream from the Y4M file. Since OGA is an audio-only container, this flag ensures only the audio stream is processed. |
-c:a libvorbis
|
Encodes the audio stream using the Vorbis codec via the libvorbis encoder. Vorbis is the default and most widely supported audio codec for the OGA/Ogg container, offering good quality at moderate bitrates. |
-q:a 4
|
Sets the Vorbis variable bitrate quality level to 4 on a scale of 0–10. Quality 4 targets roughly 128–160 kbps and is FFmpeg's recommended default — it produces perceptually transparent audio for most content while keeping file sizes reasonable. |
output.oga
|
Specifies the output file with the .oga extension, which tells FFmpeg to wrap the encoded Vorbis audio in an audio-only Ogg container. The .oga extension distinguishes this audio-only Ogg file from .ogg files that may contain video. |
Common Use Cases
- Extracting narration or commentary audio from a lossless Y4M capture produced by a video processing pipeline like AviSynth or VapourSynth.
- Pulling the audio track out of a Y4M intermediate file generated during a multi-pass video encoding workflow to archive or review it separately.
- Converting raw audio from a Y4M test clip into a distributable OGA file for use in open-source or web-based media players that support the Ogg container.
- Recovering the audio from a Y4M file created by a frame server or lossless capture tool when the video content is no longer needed.
- Producing an OGA audio file from a Y4M source for embedding in a web application, since OGA/Vorbis has broad HTML5 browser support.
- Archiving the audio component of a Y4M quality-reference clip in a compressed but high-fidelity format to save storage space.
Frequently Asked Questions
Y4M is primarily a video-centric format designed for raw frame piping, and many Y4M files contain no audio track at all — they are silent by design. If your Y4M file has no audio stream, FFmpeg will produce an empty or invalid OGA file and may report an error like 'Output file does not contain any stream'. Before using this tool, you can verify whether your Y4M file has audio by checking its source — for example, whether it was piped from a tool that also forwarded an audio stream.
Yes, the Vorbis encoder used here is a lossy codec, so some audio information is discarded during encoding. The default quality setting of 4 on Vorbis's 0–10 scale targets approximately 128–160 kbps and is generally considered transparent for most listening. If the source audio in the Y4M file is uncompressed PCM, this will be the first and only lossy encoding step, so quality loss is minimized compared to re-encoding already-compressed audio.
The quality is controlled by the -q:a flag, which accepts values from 0 (lowest quality, smallest file) to 10 (highest quality, largest file). The default used here is 4. To get higher fidelity output, change -q:a 4 to -q:a 7 or higher in the command: ffmpeg -i input.y4m -vn -c:a libvorbis -q:a 7 output.oga. For archival purposes, consider -q:a 9 or 10, though the file size will increase noticeably.
Yes — OGA supports FLAC audio streams, which would give you lossless compression. To do this, replace -c:a libvorbis -q:a 4 with -c:a flac in the command: ffmpeg -i input.y4m -vn -c:a flac output.oga. This is especially worthwhile if your Y4M file contains uncompressed audio, since FLAC preserves every bit of the original. Note that FLAC inside OGA has slightly less device support than Vorbis, though most modern media players handle it correctly.
Y4M files carry virtually no metadata — the format header contains only technical parameters like frame rate, pixel format, and dimensions. There are no embedded title, artist, or other ID tags to transfer. Your OGA output will have no metadata tags unless you add them manually using FFmpeg's -metadata flag, for example: ffmpeg -i input.y4m -vn -c:a libvorbis -q:a 4 -metadata title='My Track' output.oga. OGA fully supports Vorbis Comment metadata, so you can add rich tags after the fact using a tool like EasyTag or MusicBrainz Picard.
Both .ogg and .oga use the same underlying Ogg container format, but .oga is the MIME-type-aligned extension specifically for audio-only Ogg files, as defined by the Xiph.Org Foundation. Using .oga signals clearly that the file contains only audio (typically Vorbis, Opus, or FLAC) and no video, which helps media players and web servers serve it with the correct audio MIME type (audio/ogg). Most software that plays .ogg files will also play .oga files without any issues.
Technical Notes
Y4M (YUV4MPEG2) is an uncompressed format primarily used as a piping intermediate between Linux video tools — it carries raw YUV frames and, less commonly, raw PCM audio. Because Y4M contains no video compression, the video portion of the file is enormous relative to its duration, making audio extraction the primary practical use of this conversion. The OGA container is an audio-only Ogg file, and when using the default libvorbis encoder, the output is lossy with a VBR quality scale (0–10). Quality level 4 is the FFmpeg default and produces a good balance of file size and perceptual transparency. OGA also supports FLAC (lossless) and Opus (modern lossy) codecs if you run the command locally with a modified -c:a flag. One important limitation: Y4M's audio support is not universally implemented — many tools that write Y4M files omit the audio stream entirely, so always verify your source file has an audio track before expecting output. The OGA format supports chapter markers in its container metadata, though FFmpeg will not automatically generate chapters from a Y4M source that has none.