Re: MPE Question

[nurul <azila@nrg.cs.usm.my>]

i see. thank you Sir.

regards,
nurul

On Thu, 2005-04-28 at 15:49, Gorry Fairhurst wrote:
> Indeed the MPE specification *DOES* allow section packing as an option. Not
> all drivers/implementations permit this.
> 
> Conversely, in ULE *ALL* compliant drivers MUST support it.
> 
> Gorry Fairhurst
> 
> On 28/4/05 6:42 am, "nurul" <azila@nrg.cs.usm.my> wrote:
> 
> > Hi,
> > 
> > Do MPE allows packing? cause as far as i concern it's only allow padding
> > while ULE allows both. Correct me if i'm wrong.
> > 
> > regards,
> > nurul
> > 
> > On Thu, 2005-04-28 at 13:22, Bernhard Collini-Nocker wrote:
> >> Siva Veerepalli wrote:
> >>> A couple of questions about MPE-FEC framing.
> >>> 
> >>> 1. The interim IP datacast standard A079 (meant to
> >>> facilitate DVB-H trials) specifies that only one
> >>> datagram should be used per MPE section i.e., no
> >>> fragmentation of IP datagram over multiple MPE
> >>> sections. However, the DVB Databroadcast specification
> >>> allows fragmentation of the IP datagram over multiple
> >>> sections. Does anyone know what the usual practice is?
> >> 
> >> In order to reduce encapsulation overhead, section packing is used, i.e.
> >> if the (remainder of an) IP packet does not fit exactly in a TS packet a
> >> subsequent IP packet may start in that TS packet as well.
> >> In order to reduce jitter and latency, section packing is not used.
> >> 
> >> You can find both on existing services.
> >> 
> >>> Do the final DVB/IP datacast standards specify this
> >>> for DVB-H?
> >> 
> >> The difficulty with section peckaing on the transmit side is that the
> >> encapsulator needs to wait for subsequent IP packets to fill an
> >> partially filled TS packet and therefor has typically a time-out
> >> associated to that waiting, ie before flushing the buffer and
> >> transmitting the final TS packet.
> >> 
> >>> 2. The MPE section has optional stuffing bytes at the
> >>> end of the section. Are these used? If yes, for what?
> >> 
> >> Whenver an IP packets leaves "enough" space in the last TS packet
> >> another IP packet could be inserted. If not wanted or needed, stuffing
> >> takes care that the empty space is filled up with pattern 0xFF.
> >> 
> >>> thanks,
> >>> Siva
> >>> 
> >>> 
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> > 
> 
>