[xiph-rtp] GStreamer Vorbis/Theora RTP implementation

[Luca Barbato]

Wim Taymans wrote:
> Good day!
> 
> Here is some feedback about the RTP drafts I gathered while implementing
> GStreamer plugins for vorbis and theora RTP payloading and depayloading.

great =)

> The following drafts were used:
> 
>  - Vorbis:
> http://svn.xiph.org/trunk/vorbis/doc/draft-ietf-avt-rtp-vorbis-01.txt
>  - Theora:
> http://svn.xiph.org/trunk/theora/doc/draft-ietf-avt-rtp-theora-00.txt
> 
> The plugins interoperate fine. They were not yet tested against an
> alternative implementation.
> 
> These are some observations:
> 
> *) Payload Length (Vorbis, Theora Figure 3, ...) Endianness is not
> explicitly
>    defined, I just assumed big endian...

corrected already for vorbis, I'll update theora now

> 
> *) Section 3: Configuration Headers. This was a little confusing, when
> talking
>    about the delivery methods (inline, in-band, out-of-band) the inline
> method is
>    not clearly described. For example:
> 
>     "For non chained streams, the RECOMMENDED Configuration
>      delivery method is inline the Packed Configuration (Section 3.1.1) in
>      the SDP as explained in the IANA considerations (Section 6.1)"
> 
>    but then section 3.1.1 and Figure 6 talks about the _in-band_ delivery method of the
>    packed configuration. I think it was meant to point to Packed Headers (Section 3.2.1).

I'll try to clarify soon

> 
> *) Vorbis 8.1 (and Theora 7.1) Stream Radio: 
> 
>     "When the streamed content changes the ....  has to be
>      sent inline in the SDP updated.  Since the [inline] method is
>      unreliable, an out of band fallback is provided."
> 
>    [inline] should be changed to in-band?

fixed

>  
> *) It's unclear what protocol/syntax one should/can/must support for the out-of-band
>    method. Is it possible to fetch a specific Ident? If yes, how? Vorbis Section 6.1.1
>    gives an SDP example:
> 
>     "The first configuration packet is inlined in the sdp, other configurations
>      could be fetched at any time from the first provided uri [using] or all
>      the known configuration could be downloaded using the second uri."
> 
>    Is this the rule? Is the first uri the currently streaming Ident? Is the second one
>    the aggregated Idents?

The idea was that you can fetch either a directory or a single file.
It should be refined...

thanks for the feedback =)

-- 

Luca Barbato

Gentoo/linux Gentoo/PPC
http://dev.gentoo.org/~lu_zero