Re: RE: Question on Continuity Counter field

["William StanisLaus" <williams77@rediffmail.com>]

Hi,
  Please refer..ISO/IEC 13818-1
2.4.3.3 Semantic definition of fields in Transport Stream packet layer, Page 44 for countinuty_counter and Page 46 for discontinuity_indicator

Well its again an implementation decision to consider or mask countinuty check based on the PID.

Best Regards,
William StanisLaus | Design Engineer - FS, Nera Dept 
email: williams@future.futsoft.com | Telephone: +91 44 24330550 Extn: 282 
Mobile: +91 98411 57902 
www.futsoft.com


On Wed, 18 Feb 2004 Allison, Art wrote :
>IMHO, if a MPEG-2 TS parser was presented with out of order packets
>identified by the same PID, a receiver failure is to be expected as the
>stream would be non-conformant.
>
>However, the continuity_counter can be the same in sequential packets (which
>are then required to be the same except for the PCR).  Also, this count may
>be discontinuous when that is indicated by the discontinuity_indicator.  So
>it is not always a monotonically incrementing field.  Given the rules for
>this 4-bit continuity_counter, it is not apparent that it is possible to use
>it to reorder packets at the MPEG-2 level.
>
>Therefore, IMHO, any lower level communication protocol must not reorder
>MPEG-2 transport stream packets that are identified by the same PID. If it
>has a potential to do so, then either constraints or an explicit method for
>restoring the order must be defined.
>
>Art
>::{)>
>Art Allison
>Director Advanced Engineering
>NAB
>1771 N St NW
>Washington DC 20036
>202 429 5418
>
>
>-----Original Message-----
> From: Tarif.Zein-Alabedeen@space.alcatel.fr
>[mailto:Tarif.Zein-Alabedeen@space.alcatel.fr]
>Sent: Friday, February 13, 2004 9:05 AM
>To: ip-dvb@erg.abdn.ac.uk
>Subject: Question on Continuity Counter field
>Importance: Low
>
>
>
>
>Hi,
>I have a question about the continuity counter field in the TS packet
>header. May be someone in this group has the right answer :
>what heppens if an MPEG receiver receives an out of order TS packet?
>that is, for the same PID, the CC field value of a received packet not
>equal to CC field value of precedent TS packet + 1
>
>Is there one standard behavior or is it implmenetation dependent?
>can CC check as the receiver be disabled?
>
>(oups, this makes 3 questions already)
>
>thank's and best regards
>
>
>T. Zein
>ALCATEL SPACE
>DRT/RST
>