MPEG to MP4, old video that plays again.

An MPEG to MP4 converter reads an MPEG-1 or MPEG-2 video and saves it again as an MP4 with H.264 picture and AAC sound, the pair that Macs, iPhones, browsers and video sites all play. This one reads the MPEG file with a small build of FFmpeg that runs inside the page, then uses the encoder built into your browser to write the MP4. Nothing is sent to a server, and the page sets no limit on length.

How to convert MPEG to MP4

1. Drop one or more files on the box, or click to choose. The endings .mpg, .mpeg, .mpe, .vob, .m2v and .m1v are accepted. The first time, the page loads its reader, about 2 MB.
2. The first picture shows big, with a line under it: the stored picture size, the size it will be shown at if that is different, the length, the frame rate, the video and sound kinds and the file size.
3. Each file is converted straight away with the settings you used last time. The bar shows how far it has got and about how long is left, and Stop ends it.
4. Change Quality (High, Good or Small) or Size, or tick Smooth interlaced lines, and the file is made again. The green line says the bitrate and about how big the MP4 will be.
5. Play the MP4 on the page, then click Download the MP4. With several files, each row has its own download, and Download all as ZIP saves them together.

What a DVD file looks like to the page

Many MPEG-2 files, including the ones from a DVD, store the picture at one size and carry a note saying how wide to show it. A widescreen NTSC DVD file stores 720 x 480 and asks for 16:9. If the MP4 kept 720 x 480 as it is, everyone in it would look thin. The page reads that note and draws the picture at the shape it should be seen, so a file like that comes out 854 x 480, and the info line shows both sizes. Size choices then cap the longest side as usual.

A DVD movie is also split into several .vob files that play one after another. Convert each file here, then join the MP4 pieces in the video merger. A .vob from a disc that is copy protected is scrambled, and this page does not break that protection, so such a file will not give a picture.

Interlaced video

Video made for old television often draws every other line in one pass and the rest in the next. On a computer screen that shows as comb-like edges on anything that moves. Tick Smooth interlaced lines and each line is mixed half and half with the one above it, which hides the comb at the price of a slightly softer picture. Leave it off for video that is not interlaced, such as most files made on a computer.

Picking size and quality

Quality sets how much data each second of picture gets, worked out from the picture size and frame rate. Take that widescreen NTSC file at 854 x 480 and 29.97 frames a second. On Good the picture gets about 0.86 Mbps and the sound is AAC at 160 kbps, so together about 1.02 Mbps, and ten minutes comes to about 76 MB. High is about 1.47 Mbps for the picture and about 122 MB for ten minutes. Small is about 0.49 Mbps and about 49 MB.

• High for home videos and anything you want to keep as the new master copy.
• Good for most films and clips. It is set for you.
• Small for videos you only need to send or post.

The size choices cap the longest side of the picture at 1920, 1280 or 854 pixels. A video that is already smaller is never stretched up. Most MPEG files are small to begin with, so Same as the video is usually right.

Which MPEG files work

MPEG-1 and MPEG-2 pictures in program streams (.mpg, .mpeg, .vob), bare video streams (.m2v, .m1v) and MPEG inside AVI. For sound: MP2, MP3, AC-3 (Dolby Digital), AAC and the 16-bit uncompressed sound used on DVDs. Sound of another kind, such as DTS, is left out, and the page says so. Transport streams (.ts, .mts) and the newer MPEG-4 files are other formats; the video converter handles those that the browser can read.

When a file will not convert

• "This file could not be read as an MPEG video." The file is not really MPEG, is damaged, or has a protected disc inside. Some files with an .mpg ending are another format.
• The MP4 has no sound but the MPEG does. Either the browser cannot encode AAC, which the summary says, or the sound is of a kind the reader does not have.
• The browser says it cannot encode H.264. Use a current Chrome, Edge or Safari. Firefox can read the MPEG but may not write the MP4.
• A very long film fails near the end. The MP4 is built in memory, so a film of several gigabytes can run out of room. Pick Small or a lower size, or convert it in parts.

Keep the original file until you have watched the MP4 all the way through. For other old formats, try AVI to MP4 or WMV to MP4.