Re: [AVT] New draft-ietf-avt-mpeg4-simple-07
Colin Perkins <csp@isi.edu> Wed, 26 February 2003 15:48 UTC
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To: Franceschini Guido <Guido.Franceschini@TILAB.COM>
cc: jan.vandermeer@philips.com, avt@ietf.org
Subject: Re: [AVT] New draft-ietf-avt-mpeg4-simple-07
In-Reply-To: Your message of "Wed, 26 Feb 2003 16:40:15 +0100." <3737D9839ED3D3408C73611BDA907A0419ED0E@EXC2K05A.cselt.it>
Date: Wed, 26 Feb 2003 10:49:51 -0500
From: Colin Perkins <csp@isi.edu>
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Guido, The paragraph you quoted continues with "When transmitting Access Units of variable duration ... the transmitter MUST use the AU-Index to encode the index information required for reordering..." which implies non-zero values to my reading. Colin --> Franceschini Guido writes: >Colin, > >your reply makes me very happy. I'd love to see this draft becoming an RFC. >So apparently it is already specified that AU-Index will never be 0 when >"useful". That is just perfect -I was assuming that 0 was an acceptable >coded value for the variable duration case-. I failed however to find such >a statement. Could you or Jan point me to it ? > >Thanks again >Guido > >-----Original Message----- >From: Colin Perkins [mailto:csp@isi.edu] >Sent: Wednesday, February 26, 2003 4:19 PM >To: Franceschini Guido >Cc: jan.vandermeer@philips.com; avt@ietf.org >Subject: Re: [AVT] New draft-ietf-avt-mpeg4-simple-07 > > >Guido, > >--> Franceschini Guido writes: >>Jan, >> >>unfortunately I have to disagree with the text you modified with respect >>to Colin's text. >>I am fine with supporting early implementations, but the wording used >>is, IMHO, not suitable. More specifically you wrote: >> >> If the "constantDuration" parameter is not present, then Access >> Units are assumed to have a variable duration, unless the AU-Index >> is present and coded with the value 0 in each RTP packet. >> >>How can a receiver implement the rule above? Should it observe 1, 10, >>1000 or infinite packets before determining that the "AU-Index is >>present and coded with the value 0 in each RTP packet" ? > >One packet is sufficient. If the Access Units have variable duration, the >AU-Index will never be zero, if they have fixed duration it will always be >zero. The rest of the paragraph you quoted makes this explicit. > >>What is the exact legacy that you want to support ? Maybe there is a >>different mechanism to support it. For example, a specific mode >>definition might IMPLY a specific "constantDuration" value, without >>writing this explicitely in the SDP. > >Not if it wishes to comply with this specification. > >Colin >_______________________________________________ >Audio/Video Transport Working Group >avt@ietf.org >https://www1.ietf.org/mailman/listinfo/avt > > >==================================================================== >CONFIDENTIALITY NOTICE >This message and its attachments are addressed solely to the persons >above and may contain confidential information. If you have received >the message in error, be informed that any use of the content hereof >is prohibited. Please return it immediately to the sender and delete >the message. Should you have any questions, please contact us by >replying to MailAdmin@tilab.com. Thank you >==================================================================== >_______________________________________________ >Audio/Video Transport Working Group >avt@ietf.org >https://www1.ietf.org/mailman/listinfo/avt _______________________________________________ Audio/Video Transport Working Group avt@ietf.org https://www1.ietf.org/mailman/listinfo/avt
- [AVT] New draft-ietf-avt-mpeg4-simple-07 jan.vandermeer
- RE: [AVT] New draft-ietf-avt-mpeg4-simple-07 Franceschini Guido
- Re: [AVT] New draft-ietf-avt-mpeg4-simple-07 Colin Perkins
- RE: [AVT] New draft-ietf-avt-mpeg4-simple-07 Franceschini Guido
- Re: [AVT] New draft-ietf-avt-mpeg4-simple-07 Colin Perkins
- Re: [AVT] New draft-ietf-avt-mpeg4-simple-07 jan.vandermeer