Extract audio from MPG video and save as AC3 Dolby Digital. Supports 5.1 surround sound. Free.

How to Convert MPG to AC3 Online

1. Upload Your MPG File: Drag and drop your .mpg or .mpeg video, or click "Add Files" to browse. Batch conversion is supported — queue several MPEG-1/MPEG-2 program streams in a single session.
2. Pick a Quality Preset or Bitrate: Default is the Highest quality preset. Use the Quality Preset dropdown (Highest through Lowest) for one-click selection, switch to Custom Bitrate to type any kbps value (the AC-3 spec tops out at 640 kbps), or pick a Constant Bitrate preset (32-384 kbps). For DVD-style 5.1 audio aim for 384-448 kbps; 192 kbps is the long-standing DVD stereo setting.
3. Set Audio Channel and Sample Rate (Optional): Audio Channel defaults to Original — keep this if you want the source layout (mono, stereo, or 5.1) preserved. Force Mono or Stereo to downmix. Audio Sample Rate also defaults to Original; AC-3 supports 32, 44.1, and 48 kHz, and DVD/Blu-ray authoring expects 48 kHz.
4. Trim and Convert: Optionally expand Trim and enter a Start Time and Duration (seconds or HH:MM:SS.sss) to extract a single scene. Click "Convert" — the audio track is demuxed and re-encoded to AC-3 in your browser session. No sign-up, no watermark.

Why Convert MPG to AC-3?

.mpg files are MPEG-1 or MPEG-2 program streams — the format DVDs, older camcorders, TiVo recordings, and DV capture tools have used since the late 1990s. The audio inside is usually MPEG-1 Audio Layer II (MP2) or LPCM, neither of which is the canonical Dolby Digital track that NTSC DVD players and home-theater receivers expect. Extracting and re-encoding to AC-3 makes the audio stream conformant for downstream authoring or playback on Dolby hardware.

• NTSC DVD authoring — ATSC A/52 / Dolby Digital is the mandated audio codec for NTSC DVD-Video; MP2 is optional only on PAL discs, so re-encoding the MPG's MP2 track to AC-3 is the safe path for region 1 mastering.
• Home-theater receivers — Yamaha, Denon, Onkyo, and Sony AV receivers ship with Dolby Digital decoders by default. Feeding them an AC-3 file over optical or HDMI gets the "Dolby Digital" indicator instead of a PCM downmix.
• Replacing a 224 kbps MP2 track — AC-3 at 192 kbps is roughly equivalent in perceived quality to MP2 at 224-256 kbps, so converting saves a small amount of bitrate for the same listening experience.
• 5.1 surround on DVD/Blu-ray — AC-3 carries up to 5.1 (front L/R, center, surround L/R, LFE) in a single stream; if the MPG already contains a multichannel mix, this conversion preserves it without a PCM blowup.
• Editing handoff — Premiere Pro, DaVinci Resolve, and Vegas Pro all import AC-3 natively, so extracting the audio gives editors a small, codec-typed asset rather than wrestling with a full MPEG-2 program stream.
• ATSC broadcast workflows — Over-the-air ATSC 1.0 stations in the US are required to deliver Dolby Digital audio, capped at 448 kbps per the ATSC specification; AC-3 is the right intermediate when prepping content for that pipeline.

MPG Audio (MP2) vs AC-3 — Format Comparison

AC-3 Bitrate Quick Guide

Frequently Asked Questions

Why does my MPG already have audio — what does converting to AC-3 actually do?

The MPG container holds video and audio elementary streams together. The audio is almost always MPEG-1 Layer II (MP2) or LPCM, not AC-3. This tool demuxes the audio, discards the video, and re-encodes to AC-3 so the result is a standalone Dolby Digital file you can mux into a different container or feed to authoring software.

What bitrate should I pick — 192, 384, 448, or 640 kbps?

For a stereo extract that mirrors classic DVD audio, 192 kbps is the de-facto standard. For a 5.1 mix headed to a DVD or ATSC broadcast workflow, 448 kbps is the ceiling defined by those specs — going higher (e.g., 640 kbps) breaks DVD compliance because the AC-3 frame exceeds the 2025-byte DVD pack payload. 640 kbps is fine for software playback, Blu-ray, or archival masters.

Will the conversion preserve 5.1 surround from the MPG?

Only if the source actually contains six channels. Most consumer MPG recordings (camcorders, DV captures, TiVo) are stereo. DVD VOB-derived MPGs and broadcast captures sometimes carry 5.1. Leave Audio Channel set to Original — if the MPG is stereo, the AC-3 will be stereo; if it's 5.1, the AC-3 will be 5.1.

My MPG contains MP2 audio. Is converting MP2 to AC-3 a quality loss?

It's a transcode, so technically yes — any lossy-to-lossy conversion loses some fidelity. In practice the difference is hard to hear at sensible bitrates. AC-3 at 192 kbps perceptually matches MP2 at roughly 224-256 kbps for stereo content. If you need a bit-identical archival copy, extract to a lossless format like WAV instead.

What sample rate should I use for DVD/Blu-ray authoring?

48 kHz. DVD-Video and Blu-ray Disc both mandate 48 kHz audio. The converter defaults to Original, which preserves the source rate — set it explicitly to 48000 Hz if you know the MPG was captured at 44.1 kHz and you need disc compliance.

Why not just keep the AC-3 inside a video container?

If your downstream tool wants a video file with Dolby Digital audio, you probably want a different conversion — for example MPG to MP4 with AC-3 selected as the audio codec, or remuxing into MKV. This page outputs a bare .ac3 elementary stream, which is what DVD authoring tools, AC-3 encoders/decoders, and standalone audio editors expect.

Which players and devices decode .ac3 files natively?

VLC, MPC-HC, mpv, PowerDVD, and Kodi all play .ac3 directly. Hardware DVD and Blu-ray players, AV receivers from Yamaha, Denon, Onkyo, Sony, Marantz, and most soundbars carry Dolby Digital decoders. macOS QuickTime and Windows Media Player don't decode AC-3 out of the box; install VLC or convert to MP3 / AAC for those.

Can I cut out a single scene's audio instead of converting the whole file?

Yes — expand Trim, set a Start Time and Duration in seconds or HH:MM:SS.sss. Only the trimmed range is encoded. For more precise frame-accurate editing after the AC-3 is generated, the Audio Cutter tool handles .ac3 input directly.

Are MPG files the same as MPEG-2 transport streams (.ts) or VOBs?

No. .mpg is typically an MPEG-1 or MPEG-2 program stream (PS), used for files and DVDs. .ts is a transport stream used for broadcast and Blu-ray, designed for error-tolerant delivery. .vob is the DVD-Video on-disc variant of MPEG-2 PS with extra navigation data. All three carry MPEG-2 video and similar audio codecs (MP2, LPCM, AC-3), but they aren't byte-compatible — this page accepts .mpg and .mpeg; convert VOB or TS sources first if needed.