Why has .mkv 10 % smaller size than .ios or m2ts?

Discussion in 'CloneBD' started by SD_J-I_88, Dec 2, 2018.

  1. SD_J-I_88

    SD_J-I_88 Well-Known Member

    Hey i started saving my BDs in M2TS and later as an .iso file, created with cloneBD only main movie with different audio tracks ripped.

    When I save them as an .mkv now, without compression i get files that are always smaller and sometimes more than 10 % smaller than the .iso version?

    Can someone explain what is the "waste" data in the m2ts files? or can link to an article where this is explained?
     
  2. Pete

    Pete Forum Admin Staff Member

    m2ts has roughly 5% header data (every TS packet, length 192, has at least 8 bytes header). Plus 3 additional and recurring non-video packets every tenth second (PAT, PMT, PCR) and another every second.

    MKV has some overhead, too, but only per frame, and then some navigational information like chapters and cues (a "time to position" map).
    The latter is entirely missing from an m2ts files, so with MKV you do, indeed, get more for less.
     
    Last edited: Dec 4, 2018
  3. SD_J-I_88

    SD_J-I_88 Well-Known Member

    Hey Pete, thx.

    And despite all these header stuff is missing in an mkv container in contrast to the m2ts stream, the mkv file is as "robust" as the m2ts file? if there occoures a "rotten bit" ?
     
  4. James

    James Redfox Development Team Staff Member

    Yes. M2TS is designed to be a "transport stream" (hence the TS in the name), for broadcasting / recording from TV.