[xiph-rtp] Re: Theora RTP header design

Andrey Filippov elphel at gmail.com
Sun Apr 10 12:19:32 PDT 2005


Ralph,

In this case (from Elphel point of view) I would vote for 32 bit alignment:
- anyway we use big frames were these 2 bytes - not a big deal;
- in the hardware designs I try to leave some room for the future
extensions that did not come to mind when developing first
implementation - these 2 bytes could later turn out to be useful;
- yes it is easier to handle 32-bit aligned data. In my case now it is
not that critical (as long as the length stays the same), but it can
simplify things for other implementations.

Andrey


On Apr 10, 2005 1:01 PM, Ralph Giles <giles at xiph.org> wrote:
> Andrey,
> 
> I know you said RTP was outside your experience, but I wanted to ask
> your opinion on a design question with the Theora RTP header design.
> 
> (That, and on one else has commented :)
> 
> We're trying to decide the length of the decoder setup id field, which
> occurs in the RTP payload header of every packet, marking through an oob
> table what set of headers the decoder should use to parse the packet.
> 
> Put succinctly, from the point of view of an embedded designer, is it
> better to save 2 bytes per packet, or have the packet data start on a 32
> bit boundary?
> 
> This won't help with the theora packet header assembly problem you have,
> but we do have a chance to make the RTP headers easier to paste on than
> the Ogg ones, and there's no explicit CRC like there is in Ogg.
> 
> Just curious,
>  -r
>


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