MPEG4 Video is the same codec that may be used with MP4 file format! It means we could convert ('repack') the file to just different container format, rewriting streams as-is without actually converting video or audio - which should be very fast (converting a long movie takes only few seconds) and wouldn't cause any quality loss. There may be various codecs used, but for the file I needed to convert, Media Player Classic (my favorite movie player, installed with K-Lite Codec Pack) shows following information after selecting File > Properties: Now, each stream is encoded using some specific codec. Each format encapsulates a set of streams, usually one video and one audio stream. To understand this method, first you need to know that media file formats are just containers (for example, MKV is Matroska). The feature we need can be found in menu File > Remux Recordings. This is a free and open source app intended mostly for video recording and streaming.

Important update : I found another way to quickly remux MKV to MP4 using OBS Studio. I keep it for reference, but it probably doesn't reflect my current knowledge and beliefs.ĭo you have a video in MKV file and you can't open it because some program (like Sony Vegas Pro) doesn't support this format? If so, you probably wonder how to convert it into some different format. Warning! Some information on this page is older than 6 years now.

Edit video length vlc