Convert VOB to M2TS — Free Online Tool
Convert DVD VOB files to M2TS (Blu-ray MPEG-2 Transport Stream) format, re-encoding the MPEG-2 video to H.264 and converting AC3 audio to AAC — transforming legacy DVD content into a modern, high-definition-compatible container suitable for Blu-ray authoring tools and AVCHD-compatible players.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your VOB file here
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Settings
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 store multiplexed MPEG-2 video and AC3 (Dolby Digital) audio in a DVD-specific container. During this conversion, the MPEG-2 video stream is fully re-encoded to H.264 (libx264) using a CRF value of 23, which balances file size and quality without targeting a fixed bitrate. The AC3 audio is transcoded to AAC at 128k. Because the codecs in both containers are fundamentally different — VOB uses MPEG-2/AC3 while M2TS expects H.264/AAC for modern use — full re-encoding of both streams is required. The output is wrapped in the MPEG-2 Transport Stream container (.m2ts), which is the standard BDAV format used on Blu-ray discs and AVCHD camcorders. Subtitle streams, if present in the VOB, can be preserved depending on the subtitle format, and multiple audio tracks are supported by both containers.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — in the browser tool this runs via FFmpeg.wasm (WebAssembly), while locally it calls your installed FFmpeg executable. Everything that follows are arguments passed to this program. |
-i input.vob
|
Specifies the input file as a VOB (Video Object) file. FFmpeg will detect the MPEG-2 video and AC3 audio streams multiplexed inside the DVD container and make them available for processing. |
-c:v libx264
|
Re-encodes the MPEG-2 video stream from the VOB using the libx264 H.264 encoder. This is a full transcode — not a stream copy — because MPEG-2 and H.264 are fundamentally different codecs and cannot be remuxed directly. |
-c:a aac
|
Transcodes the AC3 (Dolby Digital) audio stream from the VOB to AAC using FFmpeg's built-in AAC encoder, which is widely supported by AVCHD players, smart TVs, and software media players that consume M2TS files. |
-crf 23
|
Sets the Constant Rate Factor for the H.264 encoder to 23, which is libx264's default and a good general-purpose quality level. For standard-definition DVD source material, this typically produces a visually clean result at a fraction of the original MPEG-2 file size. Lower values (e.g., 18) increase quality and file size. |
-b:a 128k
|
Sets the AAC audio bitrate to 128 kilobits per second. This is sufficient for stereo audio from a typical DVD soundtrack, though if the source VOB contains a high-bitrate 5.1 AC3 surround track, increasing this to 192k or 256k will better preserve the audio fidelity. |
output.m2ts
|
Specifies the output filename with the .m2ts extension, which tells FFmpeg to wrap the encoded H.264 video and AAC audio in an MPEG-2 Transport Stream container formatted for BDAV (Blu-ray Disc Audio-Video) use, compatible with Blu-ray authoring tools and AVCHD-capable players. |
Common Use Cases
- Importing DVD rips into Blu-ray authoring software (such as Nero Blu-ray or Sony DVD Architect) that requires M2TS-wrapped H.264 content
- Archiving a personal DVD collection in a modern container that is compatible with AVCHD-capable Blu-ray players and PlayStation consoles
- Preparing VOB footage ripped from home-recorded DVDs for editing in video software that natively handles M2TS files, such as Sony Vegas or CyberLink PowerDirector
- Converting DVD camcorder output (stored as VOB) into AVCHD-compatible M2TS for use with AVCHD-aware media players and smart TVs
- Reducing the file size of MPEG-2-encoded VOB content by leveraging H.264's superior compression efficiency before storing on a NAS or media server
- Transcoding DVD menu-free VOB rips into an M2TS stream suitable for streaming to a PlayStation 3, PlayStation 4, or Panasonic VIERA TV over DLNA
Frequently Asked Questions
Yes, there is a generational quality loss because the MPEG-2 video from the VOB must be fully decoded and re-encoded to H.264 — this is a transcoding step, not a lossless remux. However, at the default CRF 23, libx264 typically produces visually excellent results from standard-definition DVD source material, and the resulting file is often noticeably smaller than the original VOB. If you need higher fidelity, lower the CRF value (e.g., to 18) in the FFmpeg command to reduce compression artifacts at the cost of a larger file.
The M2TS container used in this tool's output is configured with AAC as the default audio codec. While M2TS technically supports AC3 audio (and Blu-ray discs commonly use it), the conversion pipeline here transcodes to AAC for broad player compatibility, particularly with AVCHD devices and software players. If you need to preserve AC3, you can modify the FFmpeg command by replacing '-c:a aac' with '-c:a ac3 -b:a 384k' and running it locally on your desktop.
VOB files use DVD bitmap subtitles (DVD-SUB/VOBSUB format), and M2TS supports subtitle streams. However, VOBSUB-format subtitles require specific handling in FFmpeg to be mapped and remuxed — the default command does not explicitly map subtitle streams. If preserving subtitles is important, you should run the command locally and add '-c:s copy' along with an appropriate subtitle stream map flag, though compatibility depends on whether your target player supports the subtitle format in an M2TS wrapper.
H.264 (libx264 at CRF 23) is substantially more efficient than MPEG-2. A typical DVD VOB file encoded in MPEG-2 at 4–8 Mbps can be re-encoded to H.264 at equivalent or better perceptible quality at 1–3 Mbps, often resulting in a 40–70% reduction in file size. For standard-definition DVD content, this compression improvement is significant because MPEG-2 was designed for an era before modern codec research. The actual reduction depends on the complexity and motion in the original footage.
The video quality is controlled by the '-crf 23' flag, where lower values mean higher quality and larger files, and higher values mean more compression and smaller files. For high-quality archiving from DVD source material, a CRF of 18 is a common choice (visually near-lossless for H.264). For smaller files where some quality loss is acceptable, values between 25 and 28 are reasonable. To change audio quality, adjust the '-b:a 128k' value — for example, '-b:a 192k' will produce noticeably better AAC audio, which can matter if the source VOB has a high-bitrate AC3 soundtrack.
Yes — on Linux or macOS you can use a shell loop: 'for f in *.vob; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "${f%.vob}.m2ts"; done'. On Windows Command Prompt, use: 'for %f in (*.vob) do ffmpeg -i "%f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "%~nf.m2ts"'. Note that re-encoding MPEG-2 to H.264 is CPU-intensive, so batch processing large VOB files will take significant time. The browser-based tool processes files individually and is best suited for single files up to 1GB.
Technical Notes
VOB files from DVD-Video discs often contain multiple program streams, including multiple audio tracks (e.g., different language dubs) and DVD bitmap subtitle streams (VOBSUB). The default FFmpeg command maps the first video and first audio stream only — if your VOB contains multiple audio tracks, you will need to run the command locally with explicit '-map' flags to include them. The M2TS container uses the MPEG-2 Transport Stream multiplexing format, which inherently adds a small overhead compared to Program Stream containers like VOB, but the overhead is negligible. One important caveat: some VOB files from commercial DVDs include CSS encryption and cannot be processed until decrypted — this tool and FFmpeg.wasm cannot bypass CSS encryption. Additionally, because MPEG-2 is an older codec without the reference frame complexity of H.264 or H.265, the re-encoding process is relatively fast compared to converting modern high-bitrate sources. The '-f vob' flag used internally when reading the input ensures FFmpeg correctly identifies the container type even if file headers are ambiguous, which is common with DVD rip files.