Convert MP4 to OGG

Ogg has been an open container since 2000, described by RFC 3533, and it has carried three different audio codecs over its life: Vorbis for most of that time, then Opus, and FLAC as well. The extension therefore tells you the box and nothing at all about the contents, which is unusual and is the source of most of the confusion around this format.

The file this page produces is an Ogg container holding Opus audio. For anything reading Ogg properly that is a better file than the Vorbis equivalent — Opus is a decade newer and better at the same size. For anything that assumed Ogg means Vorbis, it is a file that will be refused, and knowing which of those you are dealing with is worth two minutes.

The check is cheap and the alternative is expensive. Convert a single short clip, drop it into whatever asked for the .ogg, and see whether it loads. If it does, convert the rest. If it does not, the tool wanted Vorbis and no setting on this page will produce that.

This is worth insisting on because the failure is quiet in the worst way: some software accepts the file, reports no error, and then plays silence, because it parsed the container and found a codec it does not implement. A folder of assets that all behave that way is discovered late, usually by somebody else.

The honest answer is that this converter cannot make one. Writing Vorbis needs an encoder that this site does not ship, and pretending otherwise by relabelling an Opus file would produce something that fails in a more confusing way than a straight refusal.

Desktop audio software fills the gap without difficulty — Audacity reads the file this page produces and exports Vorbis, and any of the usual command-line tools will do it in one line. That is a reasonable route: extract here, convert there, and keep the intermediate as the thing you re-encode from if the requirement changes again.

Almost always licensing history. Ogg and its codecs were free of patent claims and free to implement at a time when MP3 and AAC were neither, which is why game engines, Linux distributions and open-source projects standardised on the extension and why the convention has outlived the reason for it.

The convention is worth respecting even where the reason has faded. An asset pipeline that expects .ogg will have build scripts, import settings and documentation built around it, and supplying an .m4a because it is technically better is the kind of small deviation that costs somebody an afternoon later.

Current browsers all play it, Linux desktops treat it as native, and VLC, Audacity and foobar2000 open it without a word. That covers development machines, web pages and most of the places these files are made and used.

Outside that it is patchy and always has been. Apple software, consumer appliances, car stereos and most portable players have never supported Ogg, and an Opus payload rather than Vorbis narrows the field slightly further. If a human being is going to listen to this file on hardware you did not choose, send them an M4A or an MP3 instead.

It compresses it a second time. The soundtrack in the MP4 was AAC, already lossy, and encoding it as Opus decodes that and throws away another portion. There is no way around it except not converting, and the honest place to say so is before the click.

The practical effect is small and depends on the material. Speech at the balanced band survives it without anything you could pick out in a listening test. Music, applause and anything with a lot of high-frequency energy is where a second pass shows, and the answer there is the high band rather than a different container.

The picture is what makes a video file large, and the picture is discarded here. A two-gigabyte screen recording and a three-hundred-megabyte export of the same session produce nearly identical audio files, because the audio in both was the same handful of megabytes a minute.

Expect somewhere around a megabyte a minute at the balanced band, less at the small one. For short game assets — a footstep, a line of dialogue, a menu sound — the file sizes are trivial and the band worth choosing on quality alone.

Xiph, who defined the container, eventually recommended splitting the extensions by content: .oga for audio, .ogv for video, .ogx for anything else, leaving .ogg to mean Vorbis audio specifically for the sake of everything already written. The recommendation arrived years after the format was in wide use, which is the usual reason a convention only half takes.

So in practice .ogg is what everything asks for and .oga is rarely seen, and a file with either extension may hold Vorbis or Opus. This page writes .ogg because that is what asset pipelines and upload forms actually name. If a specification you are working to says .oga, renaming the downloaded file is safe — the container and the codec are identical either way.

Up to a hundred files in one batch on the free tier, each with its own progress, all downloadable together as a ZIP. Since the work happens on your own machine there is no queue and no per-file allowance to run out of halfway through.

For an asset pipeline that makes this usable as a real step rather than a one-off. The caution from the second section still stands: verify one converted file inside the actual project before running the batch, not after.

The decode and encode run inside the browser tab using the codecs already on your machine, so nothing carrying the file is sent anywhere. You can watch the network tab during a conversion and see it for yourself.

For source material under a licence, an NDA or simply an unreleased build, that removes a question rather than answering one. There is no server copy to ask about, no retention period to read, and no account attached to what you converted.