Re: How does MPE handle the last byte?

[Patrick Cipiere <Patrick.Cipiere@udcast.com>]

alain.ritoux@6wind.com wrote (>):

> To keep in sync whith what is done in the DVB world, maybe the
> ULE-method should force padding & stuffing to be done also with 0xff,
> (as in the ENC-Method).

Yes, we should definitely be conformant with existing standards.
This one is not DVB but ISO/IEC 13818-1 (mpeg2)

> To have it simple, maybe then, in the ULE, the end-indicator should
> be set to 0xffff (instead of 0x0000), which of course would forbid SNDU
> with such a length field, but is it a big deal ?

In the ISO/IEC 13818-1 and DVB standards, the unused bits/bytes are
most of the times (always?) set to 1 (0xff for bytes), so i guess we
should keep that.

In ISO/IEC 13818-1 it is not said that a 0xff byte marks the end
of a payload, but when a payload ends the stuffing bytes should
(must?) be 0xff. The end of the payload is known by the upper layer: section
(MPE being one of the numerous sections available: datagram section)

So if in the ULE, `end-indicator' is a marker, 0xffff might not be the
right choice, 0x0000 would look more natural
Anyway, i do not see the reason why we need an `end-indicator' marker.
Like MPE, the SNDUs carry a length information which is enough for
this layer to extract the information from the mpeg2 layer.

Patrick.
-- 
UDcast: Full IP over Broadcast Media

Phone:  (+33) (0)4 93 00 16 99
Mobile: (+33) (0)6 14 21 55 98
Fax:    (+33) (0)4 93 00 16 61                 http://www.UDcast.com