Convert VOB to 3GPP — Free Online Tool
Convert DVD VOB files to 3GPP format for playback on mobile devices, transcoding MPEG-2 video to H.264 and AC3 audio to AAC — making DVD content accessible on smartphones and 3G-compatible players. This tool runs entirely in your browser with no file uploads required.
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 content as MPEG-2 video with AC3 (Dolby Digital) audio, a format designed for high-capacity optical discs rather than mobile consumption. During conversion, the MPEG-2 video stream is fully re-encoded to H.264 (libx264) using a CRF value of 23, which produces a dramatically smaller file while preserving acceptable visual quality. The AC3 audio track is transcoded to AAC at 64kbps — a codec and bitrate pairing optimized for mobile bandwidth constraints. The output is wrapped in a 3GPP container (.3gp) with the faststart flag applied, which relocates the MP4-style metadata atom to the beginning of the file so playback can begin before the file is fully downloaded. Subtitle streams and secondary audio tracks present in the VOB file are not carried over, as the 3GPP container does not support them.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool. In the browser-based version 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 reads the MPEG-2 Program Stream structure of the VOB, demuxing the video, AC3 audio, and any subtitle or navigation packs it contains. |
-c:v libx264
|
Re-encodes the MPEG-2 video stream from the VOB to H.264 using the libx264 encoder — a dramatic compression improvement over MPEG-2 that makes DVD-resolution content practical for mobile storage and streaming. |
-c:a aac
|
Transcodes the AC3 (Dolby Digital) audio track from the VOB to AAC, which is the audio codec required by the 3GPP container and natively supported by virtually all mobile devices. |
-crf 23
|
Sets the Constant Rate Factor for H.264 encoding to 23, FFmpeg's default, which targets a balanced quality-to-file-size ratio suitable for DVD-resolution content on mobile screens. Lower values (e.g., 18) produce higher quality at larger file sizes. |
-b:a 64k
|
Sets the AAC audio bitrate to 64kbps — a bitrate optimized for 3G mobile playback where bandwidth is limited, and appropriate for the small speakers on mobile devices that the 3GPP format targets. |
-movflags +faststart
|
Moves the 3GP container's metadata (moov atom) to the beginning of the output file, enabling progressive playback — the video can start playing on a mobile device before the entire file has been transferred. |
output.3gp
|
The output filename with the .3gp extension, which signals the 3GPP container format. This file will be playable on mobile phones, embedded players, and any device or app with 3GPP support. |
Common Use Cases
- Transferring a DVD home movie rip to an older Android or feature phone that only supports 3GPP playback
- Preparing DVD lecture or training content for distribution over 3G mobile networks where bandwidth is limited
- Creating a mobile-compatible preview clip from a VOB chapter file without needing desktop software
- Archiving a small, mobile-friendly version of a DVD concert or event recording alongside the original VOB
- Sending a short VOB-sourced video clip via MMS or mobile messaging apps that require 3GPP format
- Testing how DVD-sourced video will look on legacy mobile hardware before committing to a full encode
Frequently Asked Questions
VOB files use MPEG-2 video, which is far less efficient than H.264, and AC3 audio at bitrates typically between 192kbps and 448kbps. The 3GPP output re-encodes video with H.264's superior compression (often 40–60% smaller for the same visual quality) and drops audio down to 64kbps AAC, which is tuned for mobile use. Additionally, VOB files often contain extra data streams — navigation packs, subtitle streams, and multiple audio tracks — that are all stripped in the 3GPP output.
No — AC3 audio is not supported in the 3GPP container, so the audio is fully transcoded to AAC at 64kbps stereo. If the source VOB contains 5.1 surround AC3, FFmpeg will downmix it to stereo during this conversion. The spatial audio information from the surround channels will be lost, though the dialogue and main audio content will remain intact.
Unfortunately, the 3GPP container format does not support subtitle streams, so any DVD subtitles — whether DVD bitmap subtitles or VOB subtitle tracks — will be dropped during conversion. If you need subtitles in the output, you would need to burn them directly into the video using a filter like -vf subtitles before encoding, though this requires the subtitle stream to be extractable from your VOB source.
The -crf flag controls video quality, with lower values producing higher quality and larger files. The default is 23; try -crf 28 for a smaller file suitable for slower mobile connections, or -crf 18 for noticeably better quality at the cost of file size. You can also adjust audio size by changing -b:a 64k to 32k or 48k — at these bitrates the difference in AAC audio quality on mobile speakers is minimal.
Yes — on Linux or macOS you can run a shell loop: for f in *.vob; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 64k -movflags +faststart "${f%.vob}.3gp"; done. On Windows Command Prompt, use: for %f in (*.vob) do ffmpeg -i "%f" -c:v libx264 -c:a aac -crf 23 -b:a 64k -movflags +faststart "%~nf.3gp". This is especially useful for converting an entire DVD's worth of VOB chapters in sequence.
Yes, if your DVD content is split across VTS_01_1.VOB, VTS_01_2.VOB, etc., you should concatenate them before converting. You can do this with FFmpeg's concat demuxer by creating a text file listing each VOB, or more simply by passing them directly: 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 64k -movflags +faststart output.3gp. The browser-based tool works best with individual VOB segments under 1GB.
Technical Notes
VOB is a constrained MPEG-2 Program Stream with a fixed sector size of 2048 bytes, and FFmpeg requires the -f vob flag to correctly demux it — particularly important for handling the PCI and DSI navigation packs that are interspersed with video data. MPEG-2 video in VOBs is typically encoded at DVD resolutions (720x480 NTSC or 720x576 PAL) with a field-based interlaced structure; the libx264 encode in this conversion does not apply a deinterlace filter by default, which can result in comb artifacts on motion if the source is interlaced. For cleaner output from interlaced DVD sources, adding -vf yadif before the output filename in the desktop FFmpeg command is strongly recommended. The 3GPP container is structurally similar to MP4 (both are based on the ISO Base Media File Format), which is why -movflags +faststart works here — it enables progressive download by writing the moov atom first. Note that 3GPP officially targets H.263 and MPEG-4 Part 2 video for the strictest 3G compatibility, but H.264 in 3GP is widely supported on any device manufactured after 2008. The output will not carry DVD chapter markers, multiple audio language tracks, or aspect ratio correction metadata that may be encoded as MPEG-2 sequence display extensions in the source VOB.