Convert MXF to MP4

Which cameras make MXF

MXF, the Material Exchange Format, is a SMPTE standard from 2004 for moving footage between cameras, editing systems and broadcasters. What is inside depends on the camera:

• Sony XDCAM and Canon XF: MPEG-2 at 50 Mbit/s, about 375 MB a minute.
• Sony XAVC and Panasonic AVC-Intra: H.264, usually 10-bit, at 50 Mbit/s and well above.
• Avid and broadcast servers: DNxHD.

The sound is uncompressed PCM, usually with each microphone channel as its own track. Premiere Pro, Avid, DaVinci Resolve and VLC open MXF; phones, browsers and chat apps do not. A day of shooting can run to hundreds of gigabytes, far too much to push through an upload site. Cameras often write an XML file beside each clip as well; Octoolo leaves those alone and lists only the media.

Choose High, Balanced or Small, not As it is

AVC-Intra and XAVC are H.264, so As it is would copy them into the MP4 untouched. That keeps every bit, but the result is still a 10-bit picture at a very high bit rate, made for editing rather than playback, and many phones, browsers and TVs cannot play it. XDCAM MPEG-2 and DNxHD are never copied into an MP4, so they are converted whichever setting you pick.

With High, Balanced or Small, the picture becomes ordinary 8-bit H.264 and the sound AAC: a file any device plays. At 1080p and 30 frames a second, High spends roughly 9 Mbit/s, a small fraction of a 50 Mbit/s original, and Balanced and Small go lower. For a quick look on a phone, Small at 720p is lighter still. To judge color or exposure precisely, look at the MXF in your editing software rather than at a review copy.

Sound channels, separate sound files and timecode

MXF usually stores each sound channel as a separate mono track, two, four or eight of them. The MP4 keeps every track, but most players play only the first, which is often the camera's channel 1. If the main microphone was recorded on another channel, switch tracks in your player's audio menu; Octoolo does not mix the channels into one.

Panasonic P2 cards and Avid's media folders keep picture and sound in separate MXF files. Converting the picture file on its own gives an MP4 without sound. Sony XDCAM and XAVC files hold both together and convert in one go.

Review MP4s are for watching. For the edit, work from the MXF originals, which carry the full picture quality and the timecode your editing software relies on, along with reel names and camera settings.

Review copies for a team

For a day's rushes, drop the whole clip folder and let the batch run: up to 500 clips at a time, encoded one after another. Under Save in, pick A folder I choose… so the MP4s go to a review folder instead of beside the MXF files, and the card's folders stay exactly as the camera wrote them. If your camera also records small proxy files, they usually sit in a folder of their own; drop just the folder with the full clips to avoid converting both.

Each MP4 keeps its clip's name, so a note like “C0042, second half” still points to the right original. Balanced at 720p makes copies light enough for a shared drive or a chat thread; High at 1080p suits a client who wants to judge focus and detail. Clips recorded without sound, such as B-roll with audio switched off, simply become silent MP4s.