[Matroska-devel] Which codec list is "current"?

David Duffy davidnduffy at yahoo.co.uk
Wed Oct 25 23:08:13 CEST 2006

----- Original Message ----
From: Mike Matsnev <mike at po.cs.msu.su>
To: Discussion about the current and future development of Matroska <matroska-devel at lists.matroska.org>
Sent: Wednesday, 25 October, 2006 12:17:18 PM
Subject: Re: [Matroska-devel] Which codec list is "current"?

>On Wed, Oct 25, 2006 at 05:19:22PM +0000, David Duffy wrote:
>> Thank-you for your reply, I will use the list you recommend then.
>> I'm actually working on a hardware player so I can't make use of any VfW stuff.
>> I have to read the codec Id and map it to one of the codec's that I have support for on the hardware platform.
>> Some of them will definitely not be supportable as they simply haven't been ported to this platform but wherever
>> possible I want to be as consistent as possible and support as much as I can.
>VFW mode has one important application - MPEG4.2 (ASP) is stored as VfW
>with the same BITMAPINFOHEADER structure from AVI. If you already
>support AVI on your device, then it should be quite easy to implement
>VfW mode.

Yes of course, my apologies, I was meaning that I don't have all the filtergraph stuff and a framework that auto selects which filter to use nor are "output pins" setup the same way.

>> As for delicate questions, if someone could be so kind as to comment on my
>> previous question about how to select tracks when stereoscopic video is
>> present that would be greatly appreciated (the hardware is designed to handle
>> 3D so I would like to make sure I select the correct track(s)). :)
>This is an unexplored area yet. I suppose you need to mark tracks as
>stereo left/right (if you want to store them separately), and mark one of
>them as default. The missing element is a pointer to another track of the same
>pair, but this should not be a problem when you only have two video tracks in
>a file.

Yes agreed.  
I'm just not clear on what to do in the unlikely event that there are multiple video tracks (i.e. more than 2) with different rankings where some are left/right and some are mono with default or forced set (again I admit this is highly unlikely and a left track could always be used on a mono system rather than having a seperate mono track).
I notice in your library that 0x55aa (Forced) is not supported and that the discussions on the mailing list that led to the creation of this flag occurred after the discussions about what to removed for a 1.0 spec. so I take it that the Forced flag is considered a part of version 2.0 and should be ignored for now?

Many thanks. :)

P.S. Does "V_MPEG4/ISO/AP" apply to AVC or is it considered part of MPEG4.2 like ASP?  (i.e. should I send such a stream to a DivX decoder or to a h264 decoder?)

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