[Matroska-general] MKV vs MP4

Steve Lhomme steve.lhomme at free.fr
Fri Oct 19 15:19:33 CEST 2007


Emanuele Fumagalli wrote:
>> The header size is about the same for all matroska files. It should be 
>> around a few KB (between 4 and 8). That excludes seeking, which is 
>> pointless if you're just streaming, which is usually put at the end 
>> anyway.
> 
> actually I would like to use it for a progressive download, so letting 
> the user be able to see the video while downloading and also perform 
> seeking.
> I already do that with an mp4 container and I was wondering if using 
> matroska I could have some advantages like smaller header at the beginning.

There are 2 ways of seeking in matroska. The Meta-Seek which just seeks 
among the level 1 elements, in your case the clusters (usuallya big 
packet of a few seconds of audio/video/subs). This one takes a very 
small size and it's usually included at the beggining. But it is not 
efficient for frame-accurate seeking.

For that there are Cues which keep a reference of all video (or audio 
sometimes) frame timecode to locate them faster. You may add that too to 
your file depending on how accurate you want your seeking to be. It 
takes a little more space in the file, maybe a few 10 KB and can be 
placed at the beggining too.

Steve



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