Role of containers and codecs
A container is a structure that bundles video, sound, and time information, and a codec is a method of compressing and restoring video or sound. The file name extension is a clue to the format, but it does not change the actual internal data. Even if you rename the MOV file to MP4, the codec and container structure remain the same.
Moyoutil checks whether the combination of H.264 and AAC for MP4 output and VP8 and Opus for WebM output is supported. Outputs that cannot be encoded in the current browser cannot be selected. Even if the support verdict is true, execution may fail due to memory or device encoder issues.
Repackaging and re-encoding
Repackaging is the act of putting compatible compressed data into a different container without recompressing it. Moyoutil, on the other hand, takes the pixels of the played video into a Canvas and re-encodes them with MediaRecorder. This method is not lossless repackaging and may change image quality, file size, and frame timing.
Processing may take as long or longer as the video plays. Keep tabs and avoid screen locks and sleep. The tool cancels its action when you move to another tab. This is not an editor that preserves subtitles, multi-voice, HDR, or original metadata, so you should keep the original if such information is important.
Frequently Asked Questions
If it's MP4, will it open on all devices?
It is affected not only by the container, but also by the codec, profile, and playback environment. Check the results on the device you will actually use.
Is there no loss of image quality if I just change the format?
This tool re-encodes and therefore does not guarantee losslessness. Start from the original and convert only as many times as you need.