Convert VOB to SWF — Free Online Tool
Convert DVD VOB files to SWF (Shockwave Flash) format by transcoding MPEG-2 video to FLV1 and AC3 audio to MP3 — all directly in your browser. This conversion is useful for embedding legacy DVD content into Flash-based web players or archived Flash multimedia projects.
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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 contain MPEG-2 video and AC3 (Dolby Digital) audio multiplexed inside a DVD container. Because SWF only supports FLV1 (Sorenson Spark) or MJPEG video and MP3/AAC audio, this conversion requires full re-encoding of both streams — there is no stream-copy shortcut available. FFmpeg decodes the MPEG-2 video frames and re-encodes them using the FLV1 codec, while the AC3 surround audio is decoded and re-encoded as stereo MP3 using the LAME encoder. The output is wrapped in an SWF container, which embeds the video and audio so it can be played back by a Flash-capable player. Any subtitle streams or multiple audio tracks present in the VOB will be dropped, as SWF supports neither.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — the open-source multimedia processing engine that handles all decoding, transcoding, and muxing for this VOB-to-SWF conversion. |
-i input.vob
|
Specifies the input VOB file. FFmpeg will demux the MPEG-2 video, AC3 audio, and any subtitle or chapter streams stored in the DVD Video Object container. |
-c:v flv1
|
Sets the output video codec to FLV1 (Sorenson Spark), the primary video codec supported within SWF containers. This triggers a full re-encode from MPEG-2, as the two codecs are incompatible. |
-c:a libmp3lame
|
Uses the LAME MP3 encoder to transcode the input AC3 Dolby Digital audio into MP3, which is one of the two audio formats the SWF container supports. The AC3 surround mix will be downmixed to stereo in this process. |
-q:v 5
|
Sets the FLV1 video quality scale to 5 on a 1–10 range, where 1 is highest quality and 10 is most compressed. A value of 5 represents a mid-range balance between file size and visual fidelity for typical DVD source material. |
-b:a 128k
|
Sets the MP3 audio output bitrate to 128 kilobits per second. This is a standard bitrate for stereo MP3 audio and is sufficient for voice and general content, though the original DVD AC3 track may have been encoded at significantly higher bitrates. |
output.swf
|
Specifies the output filename and tells FFmpeg to wrap the encoded FLV1 video and MP3 audio into an SWF (Small Web Format) container, producing a Flash-compatible file. |
Common Use Cases
- Embedding DVD-sourced video clips into legacy Flash-based websites or e-learning platforms that relied on SWF for multimedia delivery
- Archiving DVD bonus features or training videos from corporate DVDs into SWF format for use in older Flash-driven intranets or kiosk systems
- Converting DVD menu videos or short promotional clips from VOB into SWF for use in archived Flash portfolios or CD-ROM multimedia projects
- Preparing DVD footage for use in Flash-based video players (such as JW Player's legacy Flash mode) where FLV1-encoded SWF was the required input format
- Digitizing and repurposing old DVD-authored educational content into SWF for compatibility with Flash-dependent learning management systems (LMS) that have not been updated
Frequently Asked Questions
Yes, there will be some quality loss. MPEG-2 in VOB is itself a lossy format, and re-encoding to FLV1 (Sorenson Spark) introduces an additional generation of lossy compression. FLV1 is an older, less efficient codec than MPEG-2, so at equivalent bitrates it will generally produce softer or blockier results, particularly in fast-motion or high-detail scenes from DVD content. Lowering the -q:v value (closer to 1) will improve quality at the cost of a larger file.
The AC3 audio — which in DVD VOB files is commonly 5.1 surround — is fully decoded and then re-encoded as stereo MP3 using the LAME encoder. SWF does not support AC3 or multichannel audio, so the surround channels are downmixed to two-channel stereo in the process. The default output bitrate is 128k, which is adequate for speech and moderate-quality music but may sound compressed for cinematic soundtracks originally recorded at 384k or higher AC3 bitrates.
No. VOB files can contain DVD subtitle streams (typically as bitmap-based subpicture data), but the SWF format has no mechanism for carrying subtitle tracks. FFmpeg will silently discard all subtitle streams during this conversion. If preserving subtitles is important, consider hardcoding them into the video using a subtitle burn-in step before converting, though this adds significant complexity to the FFmpeg command.
By default, FFmpeg will select the first audio stream in the VOB file, which is typically the primary language track. SWF supports only a single audio track, so all additional language tracks will be discarded. If you need a specific language track, you can add the flag -map 0:v:0 -map 0:a:N to the FFmpeg command, replacing N with the zero-based index of the audio stream you want to keep.
To change video quality, modify the -q:v value: lower numbers (e.g., -q:v 1) produce higher quality at larger file sizes, while higher numbers (e.g., -q:v 10) produce smaller files with more compression artifacts — the valid range for FLV1 is 1 to 10. To change audio quality, modify the -b:a value, for example -b:a 192k or -b:a 256k for better MP3 audio fidelity from the original AC3 source. These two parameters let you balance output quality against file size independently.
Yes. On Linux or macOS you can use a shell loop: 'for f in *.vob; do ffmpeg -i "$f" -c:v flv1 -c:a libmp3lame -q:v 5 -b:a 128k "${f%.vob}.swf"; done'. On Windows Command Prompt, use: 'for %f in (*.vob) do ffmpeg -i "%f" -c:v flv1 -c:a libmp3lame -q:v 5 -b:a 128k "%~nf.swf"'. Note that each VOB file requires a full re-encode of both video and audio, so batch processing can be time-intensive for long DVD content.
Technical Notes
VOB files frequently span multiple segments (VTS_01_1.VOB, VTS_01_2.VOB, etc.) on a DVD. If your source is a set of split VOB segments rather than a single concatenated file, you may need to merge them first using FFmpeg's concat demuxer or by passing a concatenated input before running this conversion. The FLV1 codec inside SWF uses Sorenson Spark compression, an older H.263-derived codec that lacks the efficiency of modern codecs — expect SWF files to be larger than equivalent MP4/H.264 output at the same visual quality. SWF as a delivery format is largely obsolete: Adobe ended Flash Player support in December 2020, and modern browsers no longer play SWF natively. This conversion is therefore best suited for archival, legacy system compatibility, or offline Flash player use rather than general web publishing. No metadata from the VOB (such as title or chapter information) is preserved in the SWF output, and chapter markers are not supported in either format's handling by this pipeline. The -f vob input flag ensures FFmpeg correctly identifies the container even if the file extension is ambiguous.