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How to convert an MPG or MPEG video to MP4 on a Mac

· 6 min read

An .mpg or .mpeg file holds MPEG-1 or MPEG-2 video, formats from the era of video CDs, DVDs, TV recorders and standard-definition camcorders. Current versions of macOS play very few of them, so QuickTime Player, Photos and iMovie usually refuse. Converting to MP4 means re-encoding the picture to H.264 and the sound to AAC, which any Mac, phone or TV will play.

What is inside an MPG file

The extension tells you less than you would like, because two different video formats share it:

  • MPEG-1 dates from the early 1990s. You find it in video CD copies, clips from early digital cameras, and old downloads. The picture is usually smaller than standard definition.
  • MPEG-2 is the format of DVDs and broadcast TV. An .mpg from a TV recorder, a capture card, a DVD camcorder, or a copied home DVD is almost always MPEG-2.

Both sit in what is called a program stream, with the audio usually stored as MPEG audio (MP2), and sometimes as Dolby Digital (AC-3) or uncompressed PCM. VOB files from DVDs are a close cousin with a different extension, and TS files carry the same kind of video in a stream built for broadcasting.

To see which one you have, open Terminal, type file and a space, drag the video into the window, and press Return:

file ~/Movies/wedding-1998.mpg

A reply that mentions “MPEG sequence, v1” is MPEG-1, and “MPEG sequence, v2” is MPEG-2. If the reply says something else entirely, such as “ISO Media”, the file is really an MP4 or MOV with the wrong extension, and renaming it may be all it needs. A file with no extension that will not open walks through that kind of detective work.

Why renaming or rewrapping does not work

Renaming .mpg to .mp4 changes the label and nothing else. The Mac still finds MPEG-2 video inside, and it still cannot decode it.

Rewrapping, where the video is moved into an MP4 container without being touched, is the lossless trick that works for MKV to MP4. It does not help here. An MP4 with MPEG-2 video inside is technically possible, but Apple’s players, phones and most TVs will not play it, so you end up with the right extension and the same problem. For a playable file the video has to be re-encoded into H.264, and the MP2 audio into AAC. Remux versus re-encode explains the difference in more detail.

The good news is that re-encoding old standard-definition video costs very little. MPEG-2 is an inefficient format by modern standards, so an H.264 copy that looks the same is usually noticeably smaller than the original.

Option 1: MPEG-1 files that QuickTime still opens

Some MPEG-1 files still open in QuickTime Player. If yours does, you can convert it without installing anything:

  1. Open the file in QuickTime Player.
  2. Choose File, Export As, and pick the largest size that is not grayed out. QuickTime only offers sizes up to the original’s resolution, and a larger size would not add detail anyway.
  3. If you are offered a choice of format, pick Greater Compatibility (H.264).
  4. Save. You get a .mov file with H.264 video inside.

A MOV with H.264 plays nearly everywhere, and turning it into an MP4 is a quick rewrap with no further quality loss: see how to convert MOV to MP4 on a Mac.

If QuickTime shows an error, or plays sound with no picture, the file is MPEG-2 or uses audio the Mac cannot read. macOS has no built-in way to convert it, because it cannot decode it in the first place.

Option 2: convert MPG to MP4 with Manatee

Manatee bundles its own conversion engine, which reads both MPEG-1 and MPEG-2, so it handles the files macOS turns away:

  1. Open Manatee and choose Convert, or drag the files straight onto its menu bar icon.
  2. Drop in one .mpg or several at once. Each file appears in the job list with its own progress.
  3. Choose MP4 as the target.
  4. When the jobs finish, each MP4 is sitting next to its original.

The originals are never modified, so you can compare before you delete anything. Everything runs on your Mac with no upload, which matters when the files are family recordings. Manatee is free for 24 hours with every feature, then $9 once.

If a file is damaged, for example a TV recording that stopped when the power went out, try Manatee’s Repair mode first. It reports the result honestly as Fixed, Partial or Not fixable. A Partial result gives you the portion that was intact, such as the first part of the recording, and nothing can bring back what was never written.

What to check in the converted file

Play the MP4, or at least skip to a few points, before you throw anything away. Three things are worth a look:

  • Moving edges. Many TV and camcorder recordings were made interlaced, meaning each frame is two half-pictures captured a moment apart. On a computer screen that can show up as fine horizontal combing on fast motion. It comes from the way the original was recorded, not from the conversion.
  • Sound at the end. Long recordings from TV boxes sometimes have gaps where the signal dropped. Check the end of the file as well as the start; if the sound has drifted, audio out of sync after a conversion explains why.
  • Sharpness on a big screen. A 480-line picture looks soft on a large display. Converting cannot add detail that was never recorded, and exporting at a higher resolution only makes the file bigger.

Once converted, the MP4s import into Photos and iMovie like any other video. If an import still fails, Photos or iMovie will not import a video lists the other usual causes. If the files are headed for email or a messaging app rather than your library, Manatee’s Shrink mode lets you type a size in MB and finds the quality that fits.

Questions

Will converting MPG to MP4 lose quality? Technically yes, because every re-encode is lossy. In practice, at sensible settings, a standard-definition MPEG-2 recording converted to H.264 looks the same to the eye. Keep the originals anyway until you have watched the copies.

What are .m2v and .mpv files? They are MPEG video with no container and no sound, often left behind by DVD authoring software that kept the audio in a separate file. They convert the same way, but the MP4 will be silent unless you add the audio back in an editing app.

Can I convert the MPG files on a DVD I own? If the disc is a home recording without copy protection, yes. Manatee is not a DVD ripper and does not remove copy protection, so commercial movie discs are outside what it does. Converting VOB files covers discs in more detail.