Method and apparatus for improved play-out packet control algorithm
View Patent ↗A method and apparatus which provides that, in a voice over network, incoming packets are analyzed and the appropriate moment to increase or decrease the nominal delay associated with a jitter buffer is determined. Hence, the nominal delay is adjusted at an appropriate moment based on network jitter characteristics. Preferably, the nominal delay is adjusted when voice activity is absent. The method and apparatus provide for improved play out of the jitter buffer, and provide improved performance.
1. A method of operating a jitter buffer having a playout queue, said method comprising: analyzing contents of the playout queue in order to determine an appropriate point in time to adjust a nominal delay associated with when packets are played out of the playout queue, wherein the contents which are analyzed comprise packets which are still sitting in the playout queue and have not been played out of the playout queue yet; and adjusting the nominal delay at the appropriate point in time such that a speed at which packets are played out of the playout queue changes, wherein the appropriate point in time comprises:
when the playout queue has been empty for a predetermined period of time, further comprising keeping track of the energy values of a last pre-determined number of frames by implementing a circular buffer of energy values.
2. A method as recited in claim 1 , further comprising increasing or decreasing the nominal delay, wherein packets are played out of the playout queue faster when said nominal delay is decreased and are played out of the playout queue slower when said nominal delay is increased.
3. A method as recited in claim 1 , wherein the step of detecting periods of low energy composes computing signal energy for each frame by summing the square of each voice sample in that frame.
4. A method as recited in claim 1 , further comprising choosing an energy threshold at every time step.
5. A method as recited in claim 4 , further comprising finding an occurrence where at least two consecutive time frames are below the threshold.
6. A method as recited in claim 5 , further comprising adjusting the second delay when the second time frame of said at least two consecutive time frames occur.
7. A method as recited in claim 1 , further comprising having the jitter buffer provide packets to a decoder, and monitoring an output of the decoder and detecting periods of low energy.
8. A method of operating a jitter buffer having a playout queue, said method comprising: analyzing contents of the playout queue in order to determine an appropriate point in time to adjust a nominal delay associated with when packets are played out of the playout queue, wherein the contents which are analyzed comprise packets which are still sitting in the playout queue and have not been played out of the playout queue yet; and adjusting the nominal delay at the appropriate point in time such that a speed at which packets are played out of the playout queue changes, wherein the appropriate point in time comprises:
when the playout queue has been empty for a predetermined period of time, further comprising having the jitter buffer provide packets to a decoder, and monitoring an output of the decoder and detecting the periods of low energy.