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List:       helix-open-discuss
Subject:    Re: [hxdiscuss] Frag offset calculation for Audio Payload 14 for MPEG1
From:       Deepak Kotian <dkotian3 () vsnl ! net>
Date:       2003-07-30 19:10:20
Message-ID: 001101c356cc$8bd64b60$172e41db () vsnl ! net
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Thanks Chris, Even I feel the same. But, I had put in the way I interpreted
from the RFC.
There is one interesting point here.
Could there be 2 fragmented frames in the same payload packet, then what
would be the frag_offset in this case.
Does RealOne care about this frag_offset.

Thanks and Regards
Deepak


----- Original Message -----
From: "Chris Sloan" <csloan@real.com>
To: "Deepak Kotian" <dkotian3@vsnl.net>
Cc: <discuss@open.helixcommunity.org>
Sent: Wednesday, July 30, 2003 9:32 PM
Subject: Re: [hxdiscuss] Frag offset calculation for Audio Payload 14 for
MPEG1 Audio ES in RFC 2250


> I think the fraq offset is used to show where the first byte of the
> payload data lies within the audio frame.  So for your example (frames
> size of 600 bytes and packet size of 500 bytes),
>
> packet 1: 500 bytes
>           0 frag offset
> packet 2: 100 bytes
>           500 frag offset
>
> I, too, think the frag offset description is vague.  This is how the
> RealOne client interprets the spec at any rate :)
>
> Chris
>
> Wednesday, July 30, 2003, 5:12:18 AM, you wrote:
>
> Deepak> Hi,
>
> Deepak> Frag_offset  calculation for Audio Payload 14 for MPEG1 Audio ES.
>
> Deepak> Suppose the audio RTP payload, which I set is 500 bytes.
>
> Deepak> The Audio Data between Frame Sync code is around 600.
>
> Deepak> The Frag_offset  when I sent the first 500 bytes is 500 , is this
correct and
>
> Deepak> so on for the Fragoffset for the next packet . If the last byte
happens to be
>
> Deepak> Frame Sync Code, then the offset would be set of zero. Is this
correct?
>
> Deepak> Can someone please give their view on this or elaborate on this
one.
>
> Deepak> The RFC 2250 says this only.
>
> Deepak> Frag_offset: Byte offset into the audio frame for the data in this
packet.
>
> Deepak> Or if some could give a TCPdump of the Audio ES for MPEG1, that
>
> Deepak> to help a lot.
>
>
>
>
>
>
> Deepak> Thanks and Regards
> Deepak> Deepak
>
>



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