Best Tools to Demux VOB to M2V and AC3

Demultiplexing (demuxing) a VOB file separates its combined audio and video data into raw, distinct elementary streams—specifically MPEG-2 video (.m2v) and Dolby Digital audio (.ac3)—without re-encoding or losing quality. This article outlines the most reliable, widely used free software tools capable of splitting VOB files into elementary streams, along with brief instructions on how they function.

1. FFmpeg

FFmpeg is a versatile, open-source command-line tool capable of handling nearly any multimedia container and codec. Because it supports stream copying, you can extract the elementary streams instantly without transcoding.

• Best For: Advanced users, automation, and cross-platform workflows (Windows, macOS, Linux).
• How It Works: Using the -c copy parameter disables re-encoding, preserving the original data bit-for-bit.
• Basic Command:

  ffmpeg -i input.vob -map 0:v:0 -c:v copy output.m2v -map 0:a:0 -c:a copy output.ac3

2. DGIndex (DGMPGDec)

DGIndex is a classic, lightweight utility designed specifically for decoding and indexing MPEG-1 and MPEG-2 streams. It is widely used in DVD authoring and video restoration pipelines.

• Best For: Users preparing files for AviSynth, VapourSynth, or standalone authoring tools.
• How to Use:
  1. Open DGIndex and load your VOB file(s) via File > Open.
  2. Navigate to the Audio menu and set Output Method to Demux All Tracks (or Demux for specific tracks).
  3. Go to File > Save Project and Demux Video.
  4. The tool will output the .m2v video file alongside the extracted .ac3 track with any audio delay specified in the filename.

3. PgcDemux

PgcDemux is tailored specifically for DVD structures. It operates on complete DVD Program Chains (PGCs), VOB sets, or individual input files, extracting audio, video, and subtitle streams accurately.

• Best For: Extracting streams directly from DVD file structures (VIDEO_TS folders) while preserving audio/video sync.
• How to Use:
  1. Open PgcDemux and browse to your input IFO or VOB file.
  2. Under the Options panel, ensure Demux video stream and Demux all audio streams are checked.
  3. Choose an output directory and click Process.

4. VobEdit

VobEdit is a low-level VOB editor that allows users to manipulate VOB files down to the navigation pack level. It includes a built-in demuxing function that handles MPEG-2 video and AC3 audio effortlessly.

• Best For: Quick GUI-based extraction from standalone VOB files without needing DVD navigation files.
• How to Use:
  1. Launch VobEdit and click Open to load the VOB.
  2. Click the Demux button on the left panel.
  3. Select Demux multiple streams, check MPEG Video and AC3 Audio, and click OK to process.

5. ProjectX

ProjectX is a Java-based DVB/MPEG demuxing utility. It specializes in repairing damaged broadcast streams, synchronizing timestamps, and splitting VOB/MPEG-2 containers into their basic component files.

• Best For: Repairing audio/video sync errors, dropped frames, or broken timecodes during the demuxing process.
• How to Use:
  1. Add the VOB file to the file list.
  2. Choose the demux action from the process settings panel.
  3. Start the process; ProjectX will fix timecode gaps and export clean .m2v and .ac3 files.