[Mp4-tech] Clock rate used for RTP timestamps

[Ratnesh Katiyar]

Hi all,
i m havng  d mp4 parser filter code which is workng for aac audio
format but while giving amr audio in mp4 this code is not workng ..
could u plz help me out from this or let me now what changes i hav 2
do in my parser code.
regards
ratnesh
On 5/8/07, Shailendra Singh <ssingh179 gmail.com> wrote:
> Hi All,
>     For H.264 and H.263, the corresponding RFCs mandate that a clock rate
> (for RTP timestamping) of 90 kHz MUST be used.
>     For MPEG-4, RFC 3016 (RTP Payload Format for MPEG-4 Audio/Visual
> Streams) says that the resolution of the RTP timestamp "is set to its
> default value of 90kHz, unless specified by an out-of-band means", i.e. a
> clock rate which is not 90 kHz is allowed if explicitly specified, for
> example, in a Session Description sent out with the "rate" parameter in the
> "a=rtpmap" line appropriately set.
>
> My questions are:
> (1) What is the need to allow a non 90 kHz clock rate for MPEG-4 when the
> other coding systems restrict it to 90 kHz?
> (2) RFC 3016 does not say anything explicitly, but is there an implied
> restriction on the range in which the clock rate should lie for MPEG-4?
>
>
> Any pointers will be appreciated.
>
> Thanks,
> Shailendra
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