Convert VOB to AAC — Free Online Tool
Extract and convert the AC3 audio from a DVD VOB file into a modern AAC stream, stripping away the MPEG-2 video, subtitle, and menu data entirely. AAC delivers better sound quality than AC3 at lower bitrates and is natively supported by iOS, Android, and web browsers — making it ideal for repurposing DVD audio content.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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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
VOB files are MPEG-2 program stream containers that typically bundle MPEG-2 video, AC3 (Dolby Digital) audio, subtitle streams (usually DVB or DVD bitmap-based), and sometimes multiple audio tracks into a single file. This conversion discards the video stream entirely and transcodes only the audio from AC3 to AAC using FFmpeg's native AAC encoder. AC3 is a lossy format, and AAC is also lossy, so this is a lossy-to-lossy transcode — there will be some generation loss compared to the original AC3 audio. The output is a raw AAC audio file (.aac), which contains no video, no subtitles, and no container metadata beyond the audio bitstream itself. If your VOB contains multiple audio tracks (e.g., different languages or commentary), FFmpeg will extract the first audio track by default.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool. In the browser-based version of this tool, this runs via FFmpeg.wasm (WebAssembly), so no software installation is needed and no files leave your device. |
-i input.vob
|
Specifies the input VOB file. FFmpeg will demux the MPEG-2 Program Stream, identifying all available streams — including MPEG-2 video, AC3 audio tracks, and any DVD subtitle subpicture streams — before selecting which to process. |
-c:a aac
|
Instructs FFmpeg to transcode the audio using its built-in AAC encoder. The AC3 (Dolby Digital) audio from the VOB is decoded to PCM and then re-encoded as AAC, which is the standard lossy audio format for Apple devices, web streaming, and modern mobile platforms. |
-b:a 128k
|
Sets the AAC output audio bitrate to 128 kilobits per second. This is the default balance point between file size and audio quality for AAC; it is roughly equivalent in perceived quality to MP3 at 128k but generally sounds cleaner due to AAC's more efficient compression algorithm. |
output.aac
|
Defines the output file as a raw ADTS AAC audio stream. The .aac extension signals to FFmpeg to write a headerless ADTS-framed bitstream — suitable for direct playback on Apple and Android devices but without a container for embedded metadata like track titles or album art. |
Common Use Cases
- Ripping the musical score or dialogue audio from a DVD you own into a lightweight AAC file for playback on an iPhone, iPad, or Android device
- Extracting audio from a DVD concert or performance recording to create an AAC audio file compatible with Apple Music or iTunes libraries
- Archiving commentary tracks from DVD extras — which are often stored as separate AC3 audio streams inside VOB files — into a shareable AAC format
- Converting DVD lecture or educational content audio into AAC for use in podcast editing software or learning management systems that don't accept VOB
- Pulling the audio from a home movie burned to DVD so it can be embedded in a video project or shared via a platform that requires AAC-compatible audio
- Reducing file size of a DVD audio rip by converting from AC3 (which often runs at 192–448 kbps) to AAC at a lower bitrate with comparable perceived quality
Frequently Asked Questions
Yes, some quality loss is unavoidable because both AC3 and AAC are lossy formats. When you transcode from one lossy codec to another, you go through a decode-then-re-encode cycle, which introduces a second round of compression artifacts. DVD audio is typically AC3 at 192–448 kbps; the default output here is AAC at 128 kbps, which will be noticeably smaller and may show some degradation at lower frequencies. If quality is critical, increase the bitrate to 192k or 256k using the FFmpeg command's -b:a flag.
Because the output format is a raw .aac audio file, FFmpeg automatically infers that no video stream should be written — the AAC container has no capacity for video. FFmpeg will emit a warning if it detects video streams in the input but will proceed correctly, writing only the transcoded audio to the output file. You do not need -vn explicitly, though adding it does no harm and can suppress the warning.
DVD VOB files often contain multiple AC3 audio streams for different languages. By default, FFmpeg picks the first audio stream. To target a specific track, add -map 0:a:1 (for the second audio track, zero-indexed) before the output filename — for example: ffmpeg -i input.vob -map 0:a:1 -c:a aac -b:a 128k output.aac. You can identify available audio streams and their language tags by running ffmpeg -i input.vob and reading the stream listing.
Replace the value after -b:a with your desired bitrate. For example, use -b:a 256k for higher quality or -b:a 96k for a smaller file. DVD AC3 audio is typically encoded at 192–448 kbps, so an AAC output of 192k or higher will preserve most perceivable detail. The default of 128k is a reasonable trade-off for general listening but may not satisfy critical or surround-sound scenarios.
Yes. FFmpeg can concatenate multiple VOB files from the same title by using the concat demuxer or by passing them as a virtual input. A common approach is: ffmpeg -i 'concat:VTS_01_1.VOB|VTS_01_2.VOB|VTS_01_3.VOB' -c:a aac -b:a 128k output.aac. This treats the segmented VOB files as a single continuous stream, which reflects how a DVD player reads them. Make sure to include all segments in playback order.
Yes. AAC encoded with FFmpeg's native aac encoder produces a standard ADTS-framed AAC bitstream that is natively supported by iOS, macOS, Android, and most web browsers via the HTML5 audio element. It is also directly importable into iTunes and Apple Music. Platforms like Spotify and YouTube accept AAC, though they typically re-encode uploaded audio anyway. For maximum compatibility with Apple ecosystem tools, the native aac encoder used here is a solid choice; libfdk_aac would offer marginally better quality at the same bitrate but is not always available in standard FFmpeg builds.
Technical Notes
VOB files use the MPEG-2 Program Stream (PS) container, which is tightly coupled to DVD authoring — they can contain multiple audio streams (AC3, DTS, LPCM, or even MPEG audio), DVD bitmap subtitles (subpicture streams), and navigation data. FFmpeg handles VOB demuxing well but requires the -f vob flag in some edge cases where the file extension is ambiguous or the stream headers are non-standard. The AC3 audio in most commercial DVDs is typically 2.0 stereo or 5.1 surround at 192–448 kbps. When downmixing 5.1 AC3 to stereo AAC (which this conversion does by default), FFmpeg applies a standard downmix matrix, but surround-channel content will be folded into the stereo image and some spatial information will be lost. If you need to preserve discrete surround channels, consider outputting to a container that supports multi-channel AAC such as M4A. The output .aac file is a raw ADTS stream with no embedded metadata container, so track title, artist, and album tags from the DVD are not preserved. For files larger than 1GB (common with full DVD titles), the FFmpeg command shown can be run locally on your desktop where no file size limits apply.