I know that .mts video files use MPEG-4 video compression. But why then don't they just have the .mp4 file name extension?

Since they don't, this means they are not digitally nor conceptually equivalent, given that one is just an advanced version of the other ("Advanced Video Coding High Definition (AVCHD) format" if that means anything), so what really is the difference between .mts and .mp4?

  • And what does it mean for editing .mts files in a video editor? Is there some sort of advantage to cutting and adding effects to them compared to .mp4

1 Answer 1


mts and mp4, in this case, are file containers. In each mts video/audio frame has a presentation timestamp or PTS embedded in a packetized elementary stream or PES whereas mp4 video/audio frames don't. Each frame, in mp4, is a raw video/audio content depends on the encoding configuration, and it does not have a timestamp; the timestamp is the frame number/count divides by the frame per second.

I am not sure where does the statement or question

for editing .mts files in a video editor

come from, but if I evaluate video contents against audio contents, I need to extract timestamps for those target video and audio contents. If the file contatiner is mp4, it would be pain in the neck since I need to know the frame number of the target contents and estimate the timestamps of them.

But it's just the challenges of handling/validating stream content from scratch; talking of video editing, even Kdenlive and Openshot can handle a mp4 file well. I think the statment was about the early version of video editor, not for today.

  • Thanks for your reply. first you say that mp4 is a pain to edit video-to-audio, but then you say Kdenlive and Openshot can edit mp4s well. Are these statements somewhat contradictory? and where does .mts fit in all this
    – user610620
    Dec 13, 2021 at 13:57
  • As i mentioned "it's just the challenges of handling/validating stream content from scratch", those video editors handle those tedious preparations and get everything easier.
    – xer-rex
    Dec 13, 2021 at 23:44
  • Is it bad practice to edit an .mts file without accompanying auxiliary files that a camcorder saves on-drive with it? Should someone convert the .mts to .mp4 or another format before editing?
    – user610620
    Dec 13, 2021 at 23:59
  • 1
    I'm not sure what kinda information happen in auxilliary files; i suspect they are thumbnails plus timestamps help you preview/fast-forward on your device/camcorder. You can try playback the mts on VLC,videolan.org/vlc. if it's doing fine on VLC, the file should be self-contained.
    – xer-rex
    Dec 14, 2021 at 0:42
  • So final verdict is it's better to edit an .mts file isntead of a .mp4 file?
    – user610620
    Feb 17, 2023 at 21:26

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