[Theora-dev] Re: [ogg-dev] OggYUV

illiminable ogg at illiminable.com
Tue Nov 8 02:03:43 PST 2005


Why not just make it OggRawFOURCC, do we really need one stream format for 
rgb, and one for yuv ?

Zen.
----- Original Message ----- 
From: "Arc" <arc at Xiph.org>
To: <ogg-dev at Xiph.org>
Cc: <theora-dev at Xiph.org>
Sent: Tuesday, November 08, 2005 3:30 PM
Subject: [Theora-dev] Re: [ogg-dev] OggYUV


> On Mon, Nov 07, 2005 at 11:11:16PM -0800, Ralph Giles wrote:
>> On Mon, Nov 07, 2005 at 10:22:50PM -0800, Arc wrote:
>>
>> > In response to (and with the help of) John Koleszar I put together an 
>> > early
>> > draft of OggYUV.. or rather, a list of header fields for it.
>>
>> Why not just wrap yuv4mpeg, one frame per packet?
>
> Honestly, that's what it'll probobally end up being functionally. 
> Practically,
> we need something a bit more flexible, as yuv4mpeg is 4:2:0 only, and we 
> need a
> wider variety of colorspaces.
>
>
>> It does suffer from not being clear on colourspace or sampling issues,
>
> It's not a lack of clarity, it's a lack of flexibility.  AFAIK, based on 
> all
> I've read and seen in implementation, it's *ONLY* 4:2:0, and while you 
> could use
> any colorspace theoretically, it makes sense to put this in the stream 
> header.
>
> I may be wrong, but even if it's more flexible than that, it certainly 
> doesn't
> support the myriad of different formats we need, or will need in the 
> future.
>
>
>> but it is dead simple.
>
> Well, it could be more simple.. ie, instead of using space-delimited ascii
> numbers, we'll use binary numbers which the Ogg bitpacker can easily 
> extract.
>
> Personally, I think that http://wiki.xiph.org/index.php/OggPCM#Format is 
> pretty
> damned simple - several orders of magnitude more so than RIFF .wav files.
>
> I think that, giving OggYUV a similar format to OggPCM, a Python script 
> using
> pyogg2 could be written to convert yuv4mpeg2 to OggYUV in under 100 lines.
>
> -- 
>
> The recognition of individual possibility,
> to allow each to be what she and he can be,
>  rests inherently upon the availability of knowledge;
> The perpetuation of ignorance is the beginning of slavery.
>
> from "Die Gedanken Sind Frei": Free Software and the Struggle for Free 
> Thought
> by Eben Moglen, General council of the Free Software Foundation
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