[Speex-dev] Re: One bug in the SVN and rtp wrapper issue

[lianghu xu]

In a word, I don't what's the standard of speex payload format.
The file doc/rtp.txt is for what?  Is it not for rtp payload?
I find that rtp.txt is more detail that draft02.txt

Which rtp docment should be followed?
Anyone else has written the RTP wrapper already?

Lianghu

On 11/22/06, Jean-Marc Valin <jean-marc.valin at usherbrooke.ca> wrote:
>
> > 1) First, I think there is a bug in  libspeex/lsp.c  line 512.
> >
> > /* hard limit ak's to +/- 32767 */
> >       if (a < -32767) a =32767;   // This line should be changed to if
> > (a < -32767) a = -32767;
> >       if (a > 32767) a = 32767;
> >       ak[j-1] = (short)a;
>
> Oops. Thanks for pointing that out. It's fixed in svn.
>
> > 2) About the RTP wrapper for VoIP
> >
> > I'd like to use the payload format defined in the SVN document rtp.txt
> > as below.
> >
> > What I'm worry about is the interoperability with other implementations.
> >
> > What's your opinion on that?
>
> Can you summarize what the issue is?
>
>         Jean-Marc
>
> > Best Regards,
> >
> > Lianghu
> >
> >
> > //************************from the SVN /doc/rtp.txt begin
> > *************************************//
> > The Speex RTP payload is defined as a header, followed by any number of
> > requests to the remote encoder and all encoded speech frames.
> >
> > +--------+----------+----------------+
> > | Header | Requests | Speech data... |
> > +--------+----------+----------------+
> >
> > The header contains only the number of frames sent
> > encoded in 6 bits
> >
> >  0 1 2 3 4 5
> > +-+-+-+-+-+-+
> > | NB frames |
> > +-+-+-+-+-+-+
> >
> > There can be any number of requests of the form
> >
> >  0 1 2 3 4 5 6 7 0 1
> > +-+-+-+-+-+-+-+-+-+-+
> > |R| ReqID | ReqVal  |
> > +-+-+-+-+-+-+-+-+-+-+
> >
> > where R is 1 when a request is following and 0 when there is no more
> > request. Each request (if R=1) is composed of a 4-bit request ID (ReqID)
> and
> > a 5-bit value (ReqVal)
> >
> > Possible values for ReqID are:
> >  0: REQ_PERSIST   ReqVal=1 for persistent requests/mode selection,
> >                   0 otherwise
> >  1: PERSIST_ACK   Acknowledge a REQ_PERSIST from the other end,
> >                   ReqVal equals the value received
> >  2: MODE          Choose the encoder mode directly
> >  3: QUALITY       Choose the encoder quality
> >  4: VBR           Set VBR on (ReqVal=1) or off (ReqVal=2)
> >  5: VBR_QUALITY   Set the encoder quality for VBR mode
> >  6: LOW_MODE      Set the encoder mode for low-band (wideband only)
> >  7: HIGH_MODE     Set the encoder mode for high-band (wideband only)
> >
> > All requests should be considered at the receiver as a suggestion and
> > compliance is not mandatory. The PERSIST_ACK should be sent upon
> receiving a
> > REQ_PERSIST request to indicate that the request has been received.
> >
> > The speech data part contains speech frames one after the other. The
> size of
> > the encoded frames can be found since the mode is directly encoded into
> each
> > frame.
> >
> > For example, a frame where we request VBR to be on with quality 8 and we
> > transmit two frames encoded at 8.35 kbps (167 bits/frame) will be:
> >
> >  0               1               2               3
> >  0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |   NB=2    |1|ReqID=2| ReqVal=0|1|ReqID=3|ReqVal=8 |0| frame 1 |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 1                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 1                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 1                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 1                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 1                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |end|                     frame 2                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 2                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 2                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 2                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |                         frame 2                               |
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > |    end frame 2    |P|P|P|P|P|P|
> > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >
> > //************************from the SVN /doc/rtp.txt end
> > *************************************//
>
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