M2TS to OGV Converter

M2TS to OGV: A Disc Stream Into an Open Container

.m2ts is what a Blu-ray disc keeps in its BDMV/STREAM folder and what an AVCHD camcorder produces once its footage has been copied to a computer. It is a transport stream, but not the plain one: BDAV framing prefixes every 188-byte packet with a four-byte arrival timestamp, giving 192-byte packets with the sync byte 0x47 sitting at offset 4 rather than offset 0. Inside is usually H.264 video with AC-3, DTS or LPCM audio, often more than one audio track, and sometimes bitmap subtitle streams.

.ogv is the opposite kind of object: Xiph.Org's Ogg container, patent-unencumbered, deliberately simple, and carrying exactly one video stream and one audio stream in practice. Converting between them is a genuine reduction, not a rewrap, and this page is mostly about knowing what gets left behind.

What the M2TS Holds and What Reaches the OGV

The one-audio-track limit is the item that surprises people most. A bilingual recording or a film with a commentary track arrives as a single stream in the output, and there is no track selector on this page to choose which. If the alternate track matters, it needs to be handled in a tool that can select streams before conversion.

How to Convert M2TS to OGV

1. Upload Your M2TS File: Drag the file onto the page or click "+ Add Files". Disc and camcorder streams are heavy — a Blu-ray title runs at 20–40 Mbit/s, so an hour is several gigabytes and the upload will dominate the job. Trim first with Video Cutter, which accepts .m2ts, if you only need a section.
2. Choose Video Codec and Audio Codec: Video Codec opens on VP8, with Theora as the alternative. Audio Codec opens on Vorbis, with Opus, FLAC and Speex also offered. Vorbis is the conventional Ogg partner; Opus is stronger at low rates; FLAC keeps the sound lossless and inflates the file.
3. Pick a Rate Control Mode That Works on Your Codec: On VP8, use Quality Preset, Constraint Quality, Constant Bitrate or Specific file size — but not Constant Quality, whose number VP8 discards. On Theora, use Constant Quality, whose slider runs 0 to 10 with higher meaning better and opens at 7.
4. Convert and Download: Set Video resolution — Keep original is pre-selected, and dropping 1080 to 720 is the single most effective way to make VP8 encoding finish sooner — then click Convert. Files upload over an encrypted connection, are decoded and re-encoded on our servers, and are deleted automatically after a few hours. No sign-up, no watermark, never shared or made public.

Choosing Between VP8 and Theora

Both are Xiph-era open codecs and both are legal Ogg payloads, but they are not interchangeable here:

• VP8 is what browsers still register for Ogg. Chromium's media type table lists VP8 as the only video codec for the Ogg container, alongside Vorbis, Opus and FLAC audio. Theora is absent from that set: Chrome disabled it by default in version 120 and Chromium removed the decoder in 123, Firefox disabled it by default in 126, and Safari never shipped it.
• Theora is the one with a working quality dial. Its Constant Quality slider is a real 0-to-10 quality parameter and responds cleanly across the range. VP8's Constant Quality slider is not passed through to libvpx at all, which falls back to its own internal default instead.
• VP8 encodes slowly at Blu-ray frame sizes. libvpx is considerably slower than an H.264 encoder for the same picture. A full 1080p title is a long job; reducing the resolution or trimming the source shortens it far more than any quality setting does.
• Neither is the right answer for a web page. If the destination is a <video> element, M2TS to WebM puts VP8 or VP9 into the container browsers actually target, and M2TS to MP4 is the universal choice. Ogg's remaining reasons to exist are software that specifically expects Xiph containers and archives with a patent-free-format policy.

Frequently Asked Questions

Why is a .m2ts different from a plain .ts if both are transport streams?

The packet framing. A plain .ts is a run of 188-byte packets each beginning with the sync byte 0x47. A .m2ts uses BDAV framing, in which every packet is preceded by a four-byte header carrying a copy-permission indicator and a 27 MHz arrival timestamp, making 192-byte packets with the sync byte at offset 4. The extension is what decides the framing when a file is written, so renaming one to the other does not convert between them — a tool that checks the layout will reject a mislabelled file.

Will both audio tracks survive if my recording has two?

No. Measured on a file carrying two AC-3 tracks tagged English and French, the Ogg output came back with one video stream and one audio stream; the second track is not written. There is no track-selection control on this page, so if the alternate track is the one you need, extract or reorder the streams in a tool that can select them before uploading. The same applies to subtitle streams: Blu-ray subtitles are Presentation Graphic bitmaps, and Ogg has nothing to put them in.

Does the interlacing on my AVCHD footage get fixed?

No, and it is worth planning around. A great deal of AVCHD material is 1080i, and there is no deinterlacing step anywhere in this pipeline — no filter is applied and none is offered. The field structure is decoded and re-encoded as it is, so moving edges keep their comb pattern, and VP8's motion compensation tends to make combing more noticeable rather than less. Deinterlace in an editor before uploading if the footage is interlaced and the result matters.

Why does the CRF slider do nothing on VP8?

Because VP8 has no constant-rate-factor mode. The interface shares one quality control across many codecs, so the slider renders, but libvpx never receives the value: with neither a bitrate nor a constrained-quality target supplied it uses its own internal defaults and says so in its log. Use Constraint Quality, which does set a real target bitrate on this encoder, or Quality Preset, which scales from the source's own bitrate. Both change the output measurably.

On Theora the quality slider seems backwards — is it?

It is correct, just different from every other page. Theora takes a quality value from 0 to 10 in which higher is better, and the control is re-ranged accordingly and opens at 7. Everywhere else on this site the same control is an H.264-style rate factor or a quantizer, where lower is better. If you switch to Theora and drag the slider down expecting a better picture, you will get a much worse one.

How much smaller will the OGV be?

A great deal, and that is the point of converting. Blu-ray and AVCHD streams run at 20–40 Mbit/s because disc capacity was not the constraint; an Ogg file at a sensible quality setting lands one to two orders of magnitude below that. The size is set by whichever rate-control mode you chose, not by the source. If you need a specific figure, Specific file size takes a target in megabytes and computes a bitrate to hit it, with an Auto Scale option that reduces the frame size too when the target is very tight.

Can I keep the H.264 video and just change the container?

No. The server always decodes and re-encodes, and in any case Ogg does not carry H.264 — the container's registered video payloads are VP8 and Theora. If your goal is to keep the original video coding and lose only the disc framing, an MP4 target is the honest answer, since MP4 and M2TS share H.264 as a video codec even though the encode still happens. Ogg is a destination you choose for openness, not for fidelity to the source.

Will the file play on a phone or a smart TV?

Almost certainly not. Ogg video is a desktop-and-software format: VLC and other ffmpeg-based players open it anywhere, but phones, televisions and set-top boxes generally do not, and browser support is limited to what Chromium registers. If the file is going to a device, convert to MP4 instead. Ogg makes sense when a specific piece of software asks for it or when an archive has a policy about patent-free formats.

Which audio codec goes with which use?

Vorbis for a general-purpose Ogg file — it is pre-selected, it is the conventional partner for Ogg video, and everything that reads Ogg reads it. Opus when the file needs to be small, since it holds up better at low bitrates and is also in Chromium's registered Ogg audio set. FLAC for an archive where the soundtrack should stay lossless, accepting a much larger file. Not Speex, which is a narrowband speech codec built for voice and quite wrong for a film or broadcast soundtrack.

How are my files handled during conversion?

Your .m2ts is uploaded over an encrypted connection, decoded and re-encoded on our servers, then deleted automatically after a few hours along with the .ogv it produced. There is no sign-up, no watermark, and nothing is shared or made public. Because disc streams are large and VP8 encoding is slow, this is one of the longer conversions on the site — trimming the source first is the most effective thing you can do to shorten it.