Convert MKV to MP4
Upload an MKV file and convert it to MP4. When the codecs already fit the target container, the conversion is lossless and near-instant; otherwise the video is re-encoded.
Upload an MKV file and convert it to MP4. When the codecs already fit the target container, the conversion is lossless and near-instant; otherwise the video is re-encoded.
Most MKV files carry H.264 or H.265 video with AAC or AC-3 audio, and MP4 accepts those directly. In that common case the tool copies the streams into the MP4 container with zero quality loss, finishing in seconds even for movie-length files.
When a stream genuinely does not fit MP4, it is re-encoded automatically at high quality. Either way you end up with a file that plays where MKV would not.
MKV is a great archive container with weak device support: TVs, phones, editors, and messaging apps regularly refuse it. MP4 is the universal currency of video. Converting changes the wrapper, not what your video looks like.
Usually none at all, because the streams are copied rather than re-encoded. A re-encode only happens when the source codec cannot live in MP4.
Instant means the streams were copied. Slow means a codec needed re-encoding, which costs real computation.
Yes. Local processing means no upload, so multi-gigabyte files are limited only by your device, not a server.