[AVT] Take two: MWPP and the marker bit
John Lazzaro <lazzaro@CS.Berkeley.EDU> Thu, 03 April 2003 18:50 UTC
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Date: Thu, 03 Apr 2003 10:49:40 -0800
From: John Lazzaro <lazzaro@CS.Berkeley.EDU>
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Subject: [AVT] Take two: MWPP and the marker bit
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Hi everyone, Looks like my mailer truncated the posting I just sent to the list, let's try again ... --- Hi everyone, Looking for input on the following MWPP issue ... MWPP supports two MIME types: mpeg4-generic for MPEG work and mwpp for general use. From draft-ietf-avt-mpeg4-simple-07.txt: Marker (M) bit: The M bit is set to 1 to indicate that the RTP packet payload contains either the final fragment of a fragmented Access Unit or one or more complete Access Units. MWPP needs "one access unit per packet" semantics for the recovery journal to work, as so for mpeg4-generic use M is defined to 1 for all packets. Currently, M is also defined to 1 for all packets for use with the mwpp MIME type, on the theory that the confusion that would result from two separate M bit definitions is best avoided. However, reading over the recent list discussion on voice codec marker bit use, I'm wondering if I should reverse this decision, and define M bit semantics for the mwpp MIME type that are in the spirit of voice-codec use (for MWPP, the right definition is to use the M bit to differentiate packets with new MIDI data from empty "guard" packets). Any input on this decision is appreciated, I'm undecided at the point ... ------------------------------------------------------------------------- John Lazzaro -- Research Specialist -- CS Division -- EECS -- UC Berkeley lazzaro [at] cs [dot] berkeley [dot] edu www.cs.berkeley.edu/~lazzaro ------------------------------------------------------------------------- _______________________________________________ Audio/Video Transport Working Group avt@ietf.org https://www1.ietf.org/mailman/listinfo/avt
- [AVT] Take two: MWPP and the marker bit John Lazzaro