RTCP XR (continued 1)

RTCP XR

block type (BT)	the constant 64 = 0x40
reserved	8 bits - MUST be set to zero unless otherwise defined
length	length of this report block in 32-bit words minus one, including the header; constant 6.
loss rate	fraction of RTP data packets from the source lost since the beginning of reception, as a fixed point number with the binary point at the left edge of the field
discard rate	fraction of RTP data packets from the source that have been discarded since the beginning of reception, due to late or early arrival, under-run or overflow at the receiving jitter buffer, in binary fixed point
burst duration	mean duration of the burstb intervals, in milliseconds
burst density	fraction of RTP data packets within burst intervals since the beginning of reception that were either lost or discarded, in binary fixed point
gap duration	mean duration, expressed in milliseconds, of the gap intervals that have occurred
gap density	fraction of RTP data packets within inter-burst gaps since the beginning of reception that were either lost or discarded, in binary fixed point
Round-trip delay	most recently calculated round-trip time between RTP interfaces, in milliseconds
end system delay	most recently estimated end system delay, in milliseconds
signal level	voice signal relative level is defined as the ratio of the signal level to overflow signal level, expressed in decibels as a signed integer in two’s complement form
doubletalk level	defined as the proportion of voice frame intervals during which speech energy was present in both sending and receiving directions
noise level	defined as the ratio of the silent period back ground noise level to overflow signal power, expressed in decibels as a signed integer in two’s complement form

Transcript

[slide100] So why do we want to send all of this information back, or to, the parties that are communicating? Well, for instance, if I know what the actual delay is in the play-out system, it means I could have, for instance, a portable speaker that's connected to my network and another network-connected speaker, and now I could send packets to them knowing how long it takes them to play out, so that if I know their placement, I could have the waves reach your head at just the right time, so that you would hear the trumpet player over here. And there are theaters, and there's a number in Germany, where the walls are covered in speakers, and they carefully time the play-out from these speakers to give you the impression you're in another room. Because it sounds like what it would sound like in this other room. Right? Because it's all just about the delays, reverberations, etc. If you recreate the audio wave front, you'll feel and hear as if you're in another room, or another place. And the cool thing about this is, of course, they can dynamically change all of that. So years ago, I was at a concert at Trinity Church, and Ted Wolf, who was a specialist in analog delay lines, had built a system where, during the concert, he had a hologram that he had built previously of the choir that was performing, and the hologram slowly elevated as the performance went on. And he changed the audio play-out so it sounded as if the chorus were floating up into the air. By carefully measuring the acoustics of this cathedral and saying, OK, how can I adjust it so that the listener will perceive that, yes, the choir really is floating up into the air. And you will believe it, because you trust your ears. This spatialized perception.