Convert Y4M to OGA — Free Online Tool
Convert Y4M (YUV4MPEG2) video files to OGA audio by extracting and encoding the audio stream to Vorbis using the Ogg container. Since Y4M is a raw, uncompressed video format often used as an intermediate in video pipelines, this tool strips the video entirely and delivers a clean, open-format Vorbis audio file ready for distribution or archiving.
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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 YUV video frames with no audio compression — and in practice, Y4M files rarely carry audio at all, as the format is primarily used as a lossless intermediate for piping between tools like encoders, filters, and compositors. When audio is present, FFmpeg extracts that audio stream and re-encodes it using the libvorbis encoder, discarding all video data. The output is an OGA file: an Ogg container holding a Vorbis audio stream, encoded at quality level 4 (a variable bitrate roughly targeting 128 kbps). The video frames — which in Y4M can be enormous in raw size — are completely dropped, resulting in a dramatically smaller output file.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, which handles all media demuxing, decoding, encoding, and muxing in this conversion pipeline. |
-i input.y4m
|
Specifies the input file — a Y4M (YUV4MPEG2) raw video file. FFmpeg reads the uncompressed YUV frame data and any audio stream present in this file as the source for the conversion. |
-c:a libvorbis
|
Sets the audio encoder to libvorbis, which encodes the output audio as Ogg Vorbis — a free, open lossy audio codec that is the standard codec for OGA files. All video streams from the Y4M source are automatically discarded since the output container (OGA) is audio-only. |
-q:a 4
|
Sets the Vorbis variable bitrate quality level to 4 on a 0–10 scale, targeting approximately 128 kbps. This is the default quality used by this tool and provides a good balance between file size and audio fidelity suitable for most speech and music content. |
output.oga
|
Specifies the output filename with the .oga extension, which signals FFmpeg to mux the encoded Vorbis audio into an Ogg container formatted as an audio-only OGA file. |
Common Use Cases
- Extracting narration or commentary audio from a Y4M file produced by a screen capture or compositing pipeline for use as a standalone audio recording
- Archiving the audio track from a Y4M intermediate produced during a video production workflow in an open, compressed format before discarding the bulky raw video
- Preparing an audio-only OGA file for web streaming or embedding on platforms that support the open Ogg Vorbis format
- Isolating a music or sound design track from a Y4M render output so it can be reviewed or edited independently in a DAW
- Converting a Y4M test file's audio component to OGA for use in automated media pipeline testing or quality assurance workflows
- Producing a lightweight Vorbis audio file from a Y4M source to share with collaborators who only need the audio portion of a raw video render
Frequently Asked Questions
No — Y4M (YUV4MPEG2) is primarily a video-only intermediate format designed for lossless frame piping between tools like x264, ffmpeg, and VapourSynth. The format specification does not define an audio stream, so the vast majority of Y4M files carry no audio whatsoever. If you are attempting this conversion and receive an OGA file with no sound, it almost certainly means your Y4M source had no audio track to begin with.
Yes — Ogg Vorbis is a lossy codec, so any audio encoded into the OGA file will undergo lossy compression. The default quality setting of -q:a 4 produces variable bitrate audio roughly equivalent to 128 kbps, which is transparent for most listening scenarios. If you need lossless audio preservation, you can switch the audio codec to FLAC using -c:a flac instead of libvorbis, which the OGA container also supports.
The -q:a flag controls Vorbis quality on a scale from 0 (lowest, around 64 kbps) to 10 (highest, around 500 kbps). The default used here is 4, which targets approximately 128 kbps. To increase quality, change the command to use -q:a 6 or -q:a 8. For example: ffmpeg -i input.y4m -c:a libvorbis -q:a 6 output.oga. Note that -q:a is specific to Vorbis VBR encoding and does not apply if you switch to the FLAC codec.
Yes — the OGA container supports FLAC, which is a lossless audio codec. To produce a lossless OGA file, replace the libvorbis codec with flac in the command: ffmpeg -i input.y4m -c:a flac output.oga. You should also remove the -q:a 4 flag, as it does not apply to FLAC encoding. Keep in mind that this only matters if your Y4M source actually contains audio, which is uncommon.
Y4M stores raw, uncompressed YUV video frames, which are extraordinarily large — a single second of 1080p Y4M video can occupy hundreds of megabytes. The OGA output contains only the audio stream, encoded with lossy Vorbis compression, and no video data at all. The size reduction is not a sign of quality loss in the audio; it reflects the complete removal of the massive uncompressed video payload and the application of audio compression to whatever audio existed in the source.
Yes — on Linux or macOS, you can use a shell loop: for f in *.y4m; do ffmpeg -i "$f" -c:a libvorbis -q:a 4 "${f%.y4m}.oga"; done. On Windows Command Prompt, use: for %f in (*.y4m) do ffmpeg -i "%f" -c:a libvorbis -q:a 4 "%~nf.oga". This is particularly useful for processing large batches of Y4M intermediates from a render pipeline where individual file sizes make browser-based conversion impractical.
Technical Notes
Y4M files contain no inherent metadata beyond basic frame rate, resolution, and colorspace headers — there are no title tags, artist fields, or embedded chapters. As a result, the OGA output will contain no meaningful metadata unless you add it manually via FFmpeg's -metadata flag. The OGA container does support rich Vorbis comment metadata and chapter markers, so downstream tagging is straightforward with tools like EasyTag or beets. One important limitation: because Y4M's specification does not formally define an audio stream structure, some Y4M files produced by certain tools may have audio that FFmpeg cannot reliably detect or decode, leading to a silent OGA output. Vorbis encoding at -q:a 4 is well-suited for speech, narration, or general-purpose audio; for music from high-fidelity sources, consider raising the quality to -q:a 6 or higher, or using FLAC for lossless output. OGA files with Vorbis audio enjoy broad support in open-source media players (VLC, MPV, Audacity) but limited native support in Apple ecosystems and older Windows environments without additional codecs.