VOB to AU Converter

How to Convert VOB to AU Online

1. Upload Your VOB File: Drag and drop or click "+ Add Files" to select one or more VOB files (typically pulled from a DVD's VIDEO_TS folder). Batch conversion is supported, and large files are accepted.
2. Pick Quality Preset: The default is "Very High (Recommended)". Step down to "High" or "Medium" for smaller files, or pick "Highest" for archival fidelity. You can also switch to Custom Bitrate (8–384 kbps) or Constant Bitrate (8, 16, 24, 32, … 320, 384 kbps) if you need an exact target — useful when matching the disc's original audio rate.
3. Set Audio Channel, Sample Rate, and Trim (Optional): Audio Channel and Audio Sample Rate default to "Original" (preserves the source stream). Override to mono or to a fixed rate (8, 11.025, 16, 22.05, 32, 44.1, or 48 kHz). Use Trim to extract a specific scene from the DVD by setting a start time and duration.
4. Convert and Download: Click "Convert". Files are processed on our servers (VOB demuxing requires server-side ffmpeg) and downloaded directly to your device — no sign-up, no watermark, no software install.

Why Convert VOB to AU?

VOB (Video Object) is the container that holds video, audio, and subtitles on every standards-compliant DVD-Video — it's MPEG program stream with AC-3, DTS, MP2, or LPCM audio multiplexed inside. AU (also called .snd or "Sun audio") is the simple, header-plus-PCM format Sun Microsystems shipped with SunOS in 1992; it became the default audio format for Java's sun.audio and javax.sound.sampled APIs and the canonical sound format on NeXT and early Unix workstations. Converting VOB to AU strips the video and any subtitle/menu tracks and writes the soundtrack into a portable, uncompressed audio container that legacy Unix software, Java applets, and scientific signal-processing toolchains can read natively.

• Java audio assets — AudioSystem.getAudioInputStream() reads AU natively without external codecs, making it the safest format for DVD-sourced sound effects or narration embedded in a Java app or applet.
• Unix / Solaris / NeXTSTEP archival — older workstation software (SoX scripts, NeXT music libraries, telephony research datasets) often expects AU with μ-law or 16-bit PCM big-endian payload. AU's 24-byte header + raw samples format is the simplest possible after raw PCM.
• Telephony and speech research — μ-law-encoded AU at 8 kHz mono matches G.711 (the standard PSTN codec) byte-for-byte, so VOB audio extracted to AU/μ-law slots into legacy IVR systems, voicemail platforms, and academic speech corpora (e.g., older TIMIT-style workflows).
• Scientific signal processing — MATLAB's audioread and Octave / SciPy (scipy.io.wavfile plus aifc/AU support) read AU directly. Useful when extracting a DVD lecture's audio for analysis.
• Lecture, commentary, and audiobook extraction — pull director commentary, language tracks, or recorded lectures off a DVD and keep them in a lossless, easily-streamable container for Unix-side processing or archival.
• Pipeline compatibility with SoX — SoX (Sound eXchange) treats AU as a first-class input/output and is the de facto Unix tool for resampling, channel-mixing, and dithering — converting VOB → AU plugs your DVD audio straight into a SoX pipeline.

VOB vs AU — Format Comparison

Bitrate & Encoding Quick Guide

Frequently Asked Questions

Why is the converted AU file so much larger than the VOB?

VOB's audio track is usually AC-3 (Dolby Digital) at 192–448 kbps, or sometimes DTS at 754–1,510 kbps — both lossy compressed. AU defaults to uncompressed PCM, which for 16-bit stereo at 48 kHz works out to 1,536 kbps. So a 5-minute DVD chapter with a 384 kbps AC-3 track (~14 MB of audio) becomes roughly 55 MB as 16-bit PCM AU. To shrink it, choose μ-law encoding (compresses 16-bit to 8-bit ~2:1) or convert to a different format like VOB to MP3 or VOB to FLAC for lossless compression.

Will the original Dolby 5.1 or DTS surround channels survive?

No. AU only formally supports mono and stereo channel layouts in its 24-byte header (the channels field is a 32-bit integer, but the format and most decoders assume 1 or 2). Any 5.1 / 7.1 source will be downmixed to stereo during conversion. If you need to preserve discrete surround channels, target a multichannel-aware format like VOB to WAV (which can carry 5.1 via WAVE_FORMAT_EXTENSIBLE) or VOB to FLAC.

My VOB came from a copy-protected DVD — will this work?

No. VOBs ripped from CSS-encrypted commercial DVDs can't be demuxed by ffmpeg until the CSS layer has been removed (typically by a ripper like HandBrake or MakeMKV first). If your VOB plays in VLC standalone, it's already decrypted and we can extract the audio. If it doesn't, decrypt the disc first, then upload the resulting VOB.

Should I pick μ-law, A-law, or PCM 16-bit for the encoding?

For voice and speech research, μ-law is the standard (it's the North American/Japanese telephone codec, defined in ITU-T G.711). A-law is the European equivalent (also G.711). Both give roughly 8-bit dynamic-range performance with ~64 kbps payload at 8 kHz mono. For music, lectures, or anything you'll do further DSP on, pick PCM 16-bit — it's lossless and matches CD quality at 44.1 kHz stereo. PCM 24-bit gives extra headroom for editing but produces files 1.5x larger than 16-bit.

Does AU support sample rates above 48 kHz like 96 kHz or 192 kHz?

Technically yes — the sample_rate field in the AU header is a 32-bit integer, so any rate is representable. In practice, however, the most common DVD source rate is 48 kHz (matching AC-3 spec) or 44.1 kHz; we offer presets up to 48 kHz which covers virtually every DVD audio track. For higher sample rates (96 kHz studio masters), the source has to actually be 96 kHz to begin with — upsampling 48 kHz DVD audio to 96 kHz just doubles the file size without adding fidelity.

Why is AU big-endian when most modern formats are little-endian?

AU stores all multi-byte values in network byte order (big-endian) because it was designed in the late 1980s on Sun SPARC workstations, which were natively big-endian, and was intended to be exchanged over networks where consumers couldn't assume the receiver's CPU endianness. Modern x86/ARM CPUs are little-endian internally, so a typical AU decoder byte-swaps on load — but this is invisible to you. The format spec and our converter always write big-endian PCM regardless of your machine.

Can I extract just one chapter or scene from the VOB?

Yes — expand Advanced Options and use the Trim control. Enter a start time (in seconds) and duration; only that range of audio is extracted. This is faster than trimming the full AU afterwards because we demux directly from the requested byte offset in the VOB. For more complex multi-segment edits, convert the whole file first and use Audio Cutter on the resulting AU.

Is AU still relevant in 2026 or should I use WAV instead?

AU is still the path of least resistance for Java audio (javax.sound.sampled reads it without third-party libraries), SoX pipelines, and legacy Solaris / NeXT archives. WAV is more common in Windows-centric workflows and has broader DAW support. If you have no specific Java/Unix requirement, VOB to WAV is the more interoperable choice — they're both lossless PCM containers with similar overhead, just different headers and byte order.

How do I batch-convert a whole DVD's worth of VOB files?

Select multiple VOB files in step 1 — VTS_01_1.VOB, VTS_01_2.VOB, etc. all upload at once and run in parallel with the same audio settings. Note that DVDs split a single title across multiple 1 GB VOB chunks; you'll get one AU per uploaded VOB. To produce one continuous AU from a multi-VOB title, the simplest path is to concatenate the source VOBs into a single file first (on the command line: cat VTS_01_*.VOB > full.vob) and then upload full.vob, or use Audio Cutter on each resulting AU to extract precise chapter ranges.