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

illiminable ogg at illiminable.com
Tue Nov 8 02:08:25 PST 2005


I just meant oggRaw, not fourcc.

The fields are going to be the same for RGB, so why make it twice as much 
work to implement.

Zen.
----- Original Message ----- 
From: "illiminable" <ogg at illiminable.com>
To: "Arc" <arc at Xiph.org>; <ogg-dev at Xiph.org>
Cc: <theora-dev at Xiph.org>
Sent: Tuesday, November 08, 2005 6:03 PM
Subject: Re: [Theora-dev] Re: [ogg-dev] OggYUV


> 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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>
>
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