[Matroska-general] Re: Where do we go from here ?

Paul Paul at msn.com
Sat May 1 09:49:10 CEST 2004


Steve Lhomme wrote:

>> Any input is *highly* welcome. (I will post mine next)
>
> So from this spare time, what can we do ? What is needed ?
> 
> First, my personal needs :
> - capture TV into Matroska (DirectShow based)
> - capture DV into Matroska (with an efficient Matroska handling)
> - reencode these captures to smaller MKV
> - burn MKV movies as DVDs
> - Musepack (MPC) in MKV/MKA
> - support for MKA in iTunes

I don't do analog captures or have a video camera to edit DV from.  I 
also do very little audio work, for instance I have never actually used 
MPC.  However, I would like to have all of my albums stored in single 
MKA's.  I would also like to be able to play them within Winamp.  (Its 
evil, but I prefer playback within Winamp 2.xx as its simpler and/or less 
overhead than other players.)

But my personal wants for Matroska right now are:

- Good MPEG-2 support
- Editing of VFR MKV files

These two items are actually linked.  There are two basic sources for 
MPEG-2 for me, and they make for different requirements.  The first is 
DVD.  It would be great to be able to copy the DVD streams directly into 
a Matroska file with the option to be able to remove the RFF flag.  This 
would save you much of the problem with mixed content DVDs where it 
switches between interlaced and progressive.  You could also add/remove 
streams to your hearts content, and mix the original audio and/or video 
with whatever other encoded methods that you prefer.

The second source of MPEG-2 is digital broadcast.  The benefits that 
apply to putting DVD material into Matroska also apply for broadcast 
material.  However, there are also some other major benefits.  

Broadcast material is subject to a lot of data errors.  This can create 
problems when trying to transcode the material to another format, or even 
just playing back the recorded MPEG data.  Some utilities/players handle 
some types of error better than others.  You end up trying different ones 
to see which has the most success with the error contained in it.  There 
are also several different MPEG-2 stream types (containers), depending on 
the source.

So, a utility is needed that reads the data stream and copies MPEG-2 
video frames into Blocks with the correct timecode for that frame.  If a 
frame, or group of frames is to badly corrupted to isolate the frame 
data, it would be skipped, and that time would be left blank.  The same 
would apply to the audio data.  This would let you create an error free 
data stream to work from where all of the data is properly synched.  It 
would also be a common system that a proper editor should be able to 
handle.

Speaking of proper editors, we need one that will edit MKV files.  As it 
stands, VDM is the only editor, and it requires a constant framerate 
file.  Matroska needs an editor that can support its advantage of 
timestamped based blocks.  


> Some of these could be done with GStreamer. And the advantage of 
> GSTreamer is that it may be working on Linux, Windows, OS X somedayfrom 
> the same code. So any tools based on these would probably be portable 
> too.

I am not qualified at all to say how feasible GStreamer is for this 
purpose.  But with the time that people have spent recently looking at 
it, I think there is a real possibility.  I don't know how flexible you 
would want to make the GStreamer editor, but it should make it more 
powerful if it were designed specifically to edit Matroska files.  Just 
import whatever type of stream into a Matroska file, and then use the 
editor to edit it.  Then there is no need to worry about compatibility 
with other container formats.  You can create files of whatever nature 
you want.


Pamel




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