Convert VOB to M4V — Free Online Tool
Convert VOB files from DVD discs into M4V format compatible with iTunes, iPhone, iPad, and Apple TV. This tool re-encodes the MPEG-2 video stream to H.264 (libx264) and transcodes the AC-3 surround audio to AAC, producing a modern Apple-friendly file that plays natively across the entire Apple ecosystem.
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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Free — no uploads, no signups. Your files never leave your browser.
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 DVD video as MPEG-2, a codec from the late 1990s that Apple devices no longer natively support for playback. During this conversion, the MPEG-2 video stream is fully re-encoded to H.264 using libx264 at CRF 23, which typically delivers near-transparent quality at roughly half the file size of the original MPEG-2 stream. The AC-3 (Dolby Digital) audio track — standard on DVDs — is transcoded to AAC at 128k, the native audio codec for iTunes and iOS. The output uses the -movflags +faststart flag, which relocates the MP4/M4V metadata atom to the beginning of the file, enabling progressive streaming and fast playback start in QuickTime and iOS apps. Subtitle streams present in the VOB are preserved in the output M4V container, which supports subtitle and chapter tracks natively.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg transcoder. In the browser, this runs via FFmpeg.wasm compiled to WebAssembly, executing the identical logic as the desktop FFmpeg binary with no server involvement. |
-i input.vob
|
Specifies the input VOB file. FFmpeg automatically detects the MPEG-2 program stream container and demuxes the embedded MPEG-2 video and AC-3 audio tracks for processing. |
-c:v libx264
|
Re-encodes the MPEG-2 video stream using the H.264 encoder (libx264). This is required because M4V does not support MPEG-2 video, and H.264 is the standard codec for iTunes and Apple device compatibility. |
-c:a aac
|
Transcodes the AC-3 Dolby Digital audio from the DVD into AAC, the native audio codec for Apple devices, iTunes, and the M4V/MP4 container. AC-3 audio is not natively supported by iOS or QuickTime without a passthrough exception. |
-crf 23
|
Sets the H.264 Constant Rate Factor to 23, the libx264 default, which targets a perceptually good quality level suitable for standard-definition DVD source material. Lower values (e.g., 18) increase quality and file size; higher values (e.g., 28) reduce file size with some visible quality loss. |
-b:a 128k
|
Sets the AAC audio bitrate to 128 kilobits per second. This is sufficient for stereo AAC audio derived from a DVD source and is the standard bitrate used by iTunes for AAC purchases. |
-movflags +faststart
|
Moves the MP4/M4V metadata ('moov' atom) to the beginning of the output file after encoding completes. This is essential for streaming and playback in iOS apps and QuickTime, allowing the player to start rendering the video before the entire file is downloaded. |
output.m4v
|
Specifies the output filename with the .m4v extension. The M4V extension signals to iTunes, QuickTime, and iOS that this is an Apple-targeted MPEG-4 video file, enabling direct import into iTunes libraries and iMovie projects. |
Common Use Cases
- Ripping a personal DVD collection into iTunes-compatible M4V files for playback on Apple TV, iPhone, or iPad without needing a disc drive
- Converting VOB files extracted from a home movie DVD into M4V so they can be imported into iMovie or Final Cut Pro for editing
- Archiving old DVD recordings of TV recordings or family events into a modern container that Apple Photos or Plex can index and stream
- Preparing DVD-sourced video content for upload to iTunes Store or distribution through Apple-ecosystem platforms that require H.264/AAC in an MP4-based container
- Converting lecture or training videos burned to DVD by an institution into M4V files playable offline on an iPhone or iPad without VLC
- Eliminating the need for DVD playback software on a Mac by converting VOB files into M4V, which QuickTime Player opens natively
Frequently Asked Questions
There is a generational quality loss because MPEG-2 is decoded and then re-encoded as H.264, meaning this is a lossy-to-lossy transcode. However, H.264 at CRF 23 is significantly more efficient than MPEG-2, so the output often looks visually equivalent to the source at a smaller file size. DVDs are also capped at standard-definition resolution (typically 480i/576i), so the source quality ceiling is already low — the H.264 re-encode at default settings is unlikely to introduce visible degradation at that resolution.
The default FFmpeg command transcodes the AC-3 audio to AAC at 128k, which by default produces a stereo downmix. If your VOB contains a 5.1 surround track and you want to preserve the multichannel layout in AAC, you can modify the command to add '-ac 6' and increase the bitrate to at least 384k: 'ffmpeg -i input.vob -c:v libx264 -c:a aac -ac 6 -crf 23 -b:a 384k -movflags +faststart output.m4v'. Note that some Apple devices and apps handle multichannel AAC better than others.
M4V is technically an MPEG-4 container (nearly identical to MP4) and can be played on most modern media players including VLC, MPC-HC, and Android devices, provided the file does not have Apple FairPlay DRM applied. Files converted by this tool contain no DRM, so the resulting M4V is functionally interchangeable with an MP4 and will play broadly. Some players may require renaming the file extension from .m4v to .mp4 if they do not explicitly list M4V in their supported formats.
This browser tool supports files up to 1GB. For larger VOB files — which are common since DVD VOB sets are split into 1GB chunks — you should run the displayed FFmpeg command directly on your desktop. Install FFmpeg from ffmpeg.org, then run: 'ffmpeg -i input.vob -c:v libx264 -c:a aac -crf 23 -b:a 128k -movflags +faststart output.m4v'. To process an entire DVD's VOB set at once, you can concatenate them: 'ffmpeg -i "concat:VTS_01_1.VOB|VTS_01_2.VOB|VTS_01_3.VOB" -c:v libx264 -c:a aac -crf 23 -b:a 128k -movflags +faststart output.m4v'.
The '-crf 23' flag controls H.264 quality using Constant Rate Factor, where lower values produce higher quality and larger files. For noticeably better quality (recommended for archiving), use '-crf 18'. For smaller files where some quality loss is acceptable, use '-crf 28'. The CRF scale for libx264 runs from 0 (lossless) to 51 (worst quality), and values between 18–28 cover the practical range for standard-definition DVD content.
VOB files store DVD subtitles as bitmap image streams (DVD subtitle format, codec 'dvdsub'), not as text. The M4V container supports subtitle tracks, but the dvdsub bitmap format used in VOBs is not compatible with the text-based subtitle formats typically used in M4V/MP4. The default command does not include subtitle mapping, so subtitles will be dropped. To burn subtitles permanently into the video, you can add '-vf subtitles=input.vob' to the command, or use a tool like HandBrake which includes OCR-based subtitle conversion for DVD sources.
Technical Notes
VOB files are raw MPEG-2 program streams with a maximum video bitrate of around 9.8 Mbps and audio stored as AC-3 (Dolby Digital) at bitrates up to 448k. Converting to M4V re-encodes the video using libx264, which at CRF 23 typically produces output at 30–60% of the original MPEG-2 bitrate for equivalent perceptual quality — a significant space saving for archival purposes. The -movflags +faststart flag is particularly important for M4V files intended for network playback, as it moves the 'moov' atom to the file header so playback can begin before the full file is downloaded. One notable limitation: DVD VOB files often contain multiple audio tracks (e.g., English AC-3 5.1 and a commentary track), and the default FFmpeg command maps only the first audio stream. Use '-map 0:a' to include all audio tracks if needed. Chapter data embedded in DVD IFO files is not stored inside individual VOB files, so chapter markers cannot be automatically transferred without parsing the IFO sidecar files separately. The M4V container does support chapters natively, making it possible to add them manually via tools like mp4chaps if the chapter timestamps are known.