ogg dev - Jun 2008 - How Ogg mappings translate into the codecs parameter in Ogg media types

2008/5/29 Ralph Giles <giles at xiph.org>:
> On 28-May-08, at 6:20 PM, Conrad Parker wrote:
>
>>  /* TODO: this should check against 42 for the relevant version numbers
*/
>>  if (op->bytes < 41) return 0;
>
> I gather this means the USE_THEORA_PRE_ALPHA_3_FORMAT #if should instead be
> based on the length of the header packet. I'm not sure why you're
bothering
> though, since you're not flagging the granulepos base counter change in
beta
> 1, which applies to a lot more content.
good point, could you fix that?

Conrad.

I received the following comment regarding the table:
> The table contains a mix of octal and hexadecimal 'escape
sequences'
> for non-printable / non-ASCII octets.
> I strongly suggest to only use a single kind of numerical escapes.
Is this feasible or even desired, or should we leave things as they are?

For reference, this is how the table looks right now:

Codec Identifier             | Codecs Parameter
-----------------------------------------------------------
 char[5]: 'BBCD\0'            | dirac
 char[5]: '\177FLAC'          | flac
 char[7]: '\x80theora'        | theora
 char[7]: '\x01vorbis'        | vorbis
 char[8]: 'Speex   '          | speex
 char[8]: 'OggMIDI\0'         | midi
 char[8]: 'CMML\0\0\0\0'      | cmml
 char[8]: '\211PNG\r\n\032\n' | png
 char[8]: '\212MNG\r\n\032\n' | mng
 char[8]: '\213JNG\r\n\032\n' | jng
 char[8]: 'CELT    '          | celt
 char[8]: 'PCM     '          | pcm
 char[9]: '\x80kate\0\0\0\0'  | kate
 char[9]: 'YUV4MPEG2'         | yuv4mpeg

(Don't expect it to look pretty without a monospaced font)

-Ivo

I agree - we should use only hex or octal, but not mixed.

Cheers,
Silvia.

On Sat, May 31, 2008 at 2:20 AM, Ivo Emanuel Gon?alves
<justivo at gmail.com> wrote:
> I received the following comment regarding the table:
>
>> The table contains a mix of octal and hexadecimal 'escape
sequences'
>> for non-printable / non-ASCII octets.
>> I strongly suggest to only use a single kind of numerical escapes.
>
> Is this feasible or even desired, or should we leave things as they are?
>
> For reference, this is how the table looks right now:
>
> Codec Identifier             | Codecs Parameter
> -----------------------------------------------------------
>  char[5]: 'BBCD\0'            | dirac
>  char[5]: '\177FLAC'          | flac
>  char[7]: '\x80theora'        | theora
>  char[7]: '\x01vorbis'        | vorbis
>  char[8]: 'Speex   '          | speex
>  char[8]: 'OggMIDI\0'         | midi
>  char[8]: 'CMML\0\0\0\0'      | cmml
>  char[8]: '\211PNG\r\n\032\n' | png
>  char[8]: '\212MNG\r\n\032\n' | mng
>  char[8]: '\213JNG\r\n\032\n' | jng
>  char[8]: 'CELT    '          | celt
>  char[8]: 'PCM     '          | pcm
>  char[9]: '\x80kate\0\0\0\0'  | kate
>  char[9]: 'YUV4MPEG2'         | yuv4mpeg
>
> (Don't expect it to look pretty without a monospaced font)
>
> -Ivo
> _______________________________________________
> ogg-dev mailing list
> ogg-dev at xiph.org
> http://lists.xiph.org/mailman/listinfo/ogg-dev
>

Hi all,

I am trying to set up the codecs table in the wiki and we have played
a bit with Dirac to find out what existing tools write into the
header.

The Schroedinger implementation by Fluendo uses (or used to use)
"KW-DIRAC" as the identifier in the Ogg header.
"BBCD" is the identifier of each of the Dirac data packages.

More recently, I read that the Dirac Sequence header will be used as
the Ogg BOS packet directly.

I'm not sure this is the best solution and I'm not sure this is a
final decision either.

I believe it has to be sorted out properly and would suggest that
until such time we take the Dirac "codecs" specification out of this
Internet-Draft.

Comments welcome!

Cheers,
Silvia.


On Sat, May 31, 2008 at 2:20 AM, Ivo Emanuel Gon?alves
<justivo at gmail.com> wrote:
> I received the following comment regarding the table:
>
>> The table contains a mix of octal and hexadecimal 'escape
sequences'
>> for non-printable / non-ASCII octets.
>> I strongly suggest to only use a single kind of numerical escapes.
>
> Is this feasible or even desired, or should we leave things as they are?
>
> For reference, this is how the table looks right now:
>
> Codec Identifier             | Codecs Parameter
> -----------------------------------------------------------
>  char[5]: 'BBCD\0'            | dirac
>  char[5]: '\177FLAC'          | flac
>  char[7]: '\x80theora'        | theora
>  char[7]: '\x01vorbis'        | vorbis
>  char[8]: 'Speex   '          | speex
>  char[8]: 'OggMIDI\0'         | midi
>  char[8]: 'CMML\0\0\0\0'      | cmml
>  char[8]: '\211PNG\r\n\032\n' | png
>  char[8]: '\212MNG\r\n\032\n' | mng
>  char[8]: '\213JNG\r\n\032\n' | jng
>  char[8]: 'CELT    '          | celt
>  char[8]: 'PCM     '          | pcm
>  char[9]: '\x80kate\0\0\0\0'  | kate
>  char[9]: 'YUV4MPEG2'         | yuv4mpeg
>
> (Don't expect it to look pretty without a monospaced font)
>
> -Ivo
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