Hi, my PVR records TV in *mts snippets of each 512MB (several of them in a row are e.g. one movie or series's episode). (They are both SD mpeg2 and HD x264 under the hood) On my Mac I need to concatenate them. I used to use Avidemux put files in Avidemux. Cut. Then: video output: copy audio output: copy output format: mpeg TS muxer (ffmpeg) or mpeg PS muxer (ffmpeg) Then I read that it creates non compliant files (?!?!?) I was recommended mkvtoolnix https://mkvtoolnix.download/downloads.html advantages: - compliant files - tracks not needed can be eliminated (video-text, subtitles, other language tracks) - FillerBytes (Nalu, Null-Bytes), can be eliminated, too => saves space but doesn't change quality/bitrate one bit disadvantage: - no "Quickview" preview in Finder - as far as I could test with mkv files from the internet they are not smooth/easy to scroll through in VLC. What do you use? Again, I don't want to encode them (change the bitrate / quality). I want to keep the original file just without the trash and not as several parts. I found this https://forums.macrumors.com/threads/convert-avchd-mts-to-mov.1308610/ but it doesn't first concatenate the snippets and cut off trash at beginning and end as far as I understand and mpegstreamclip is missing a component to read *mts.