Customize a mkv file

[binnyshah]

Hi,
I want to customize my mkv file ..as in I want to add my own header to an existing mkv file...How can I achieve that?

[guns1inger]

What do you mean by header ? Do you mean a short section of video ahead of the existing video ?

Create a video clip that matches exactly all the main parameters of the existing clip - framerate, resolution, codec settings etc., including audio.

Load the header clip into AVI Demux, append the existing video, then output a new file. If offered, use smart rendering.

Note - this will screw the timing of any associated subtitles, embedded or external, except for those that are hard subbed.

[binnyshah]

Thanks guns1inger....but
By Header , I mean some text...the purpose is to add some encryption...so that the file cannot be played on any video player unless decrypted....How can I add some such text to a mkv file?

I am working on a project wherein a new hardware is to be created which kinda acts like a dvd player...This new hardware will contain the operating system and media player. Video files will be played using this hardware. But those video files will be further encrypted...and can be decrypted only through the hardware...so that they can be played only on our hardware...so say for example we use dvix as codec...we shall further encrypt it....and customize the media player to first use our decryption algorithm and only then use the dvix codec to further decrypt it.

[davexnet]

There's going to be hardware associate with this? What are you referring to?

[guns1inger]

mkv is an open format, so what you ask is not appropriate. You would have to make proprietary changes to the mkv format (thus making it no longer mkv) to accommodate your needs.

[Gavino]

I don't see the point of the original question.
If the file is only to be decrypted and played by custom hardware/software, why does it need to be an mkv file at all? The encrypted file doesn't have to look anything like the original mkv.

And if the OP is clever enough to design such hardware/software, why such a basic question?

[binnyshah]

there are multiple firms associated with this....firm A is gonna give us mkv file..firm B makes the hardware device..this device is just like a dvd player..will have the operating system and media player loaded...our company i.e. Firm C will load the customised operating system and media player into the hardware..the file given by firm A should be played only on the hardware designed by firm B...and hence we have to encrypt the mkv file given by firm A and customize vlc to add the decryption logic...I hope I am not confusing everyone...
Basically I need to customize mkv file ...add some header to it..

[guns1inger]

Sounds like all involved are way over their heads and haven't really thought this through. The place you need to start is here : http://www.matroska.org/

[binnyshah]

ya maybe...because this entire video files,media player etc concept is new to all of us...
basically the project we have got is something like this:

our client needs to sell some media files....these files are sold on a pendrive...also they sell the hardware only on which this pen drive can be viewed....
to make this possible i.e. to have the media files playable only on the hardware we need to add some encryption to the media file(which is mkv) and the decryption logic in the vlc player which will be loaded ingto the hardware...we have thaught of adding some header to the mkv file and changing the file format...vlc will then be customised t remove that header....change back the format to mkv and then play it like it plays any other mkv file....
pls let me ow how else can we achieve this..

[guns1inger]

Learn how to program.

Why should anyone tell you for free how to make these changes so you can take these free and open products and turn them into commercial ones ?

Why not just use some form of encrypted compression to hide the file, and have your player decrypt and expand it for playback ?

So far you sound like a bunch of guys who sat around, came up with something you think may be cool, and are now looking for someone else to actually do most of the work for. That's fine, if you are honest up front about it. However if this is a commercial venture you should either employ someone with the expertise, or sell your concept to someone who can develop it instead. At the moment it just seems like you want someone to do your work for you for nothing, which is not very cool at all.

[binnyshah]

We are a group of software developers...but none of us have worked with media files....and we are trying our best to use open source products....surf and find different things...and I beleive that is what Forums are for....to guide you with your path ahead...atleast in fields of our expertise we have guided people through different forums....and for free...
Thanks for the advice anyways

[jagabo]

Why do you even have to ask this question? You just prepend some data before the encrypted MKV data. You're outside the MKV spec so you can do whatever you want.

[custom header data][encrypted MKV file]

The player then checks for the custom header before decrypting the MKV file for playback.

If you want to implement MKV's own encryption you can follow their spec: http://www.matroska.org/technical/specs/notes.html#Encryption

[binnyshah]

Thanks a ton Jagabo

[Gavino]

we are trying our best to use open source products....

I hope you plan to comply with the licensing conditions for any open source software you incorporate into a commercial product.