Adaptive play-out buffers and clock operation in packet networks

Abstract

Methods and apparatus are described for a play-out buffer. A method includes writing a data packet into a jitter buffer at a write address specified by a write address generator; incrementing the write address generator; generating the difference between the write address and a current read address specified by a read address generator; reading a data packet from the jitter buffer from the current read address specified by the read address generator; generating a new read address based on the difference between the write address and the current read address by the read address generator. An apparatus includes a jitter buffer; a write address generator for storing a write address; a read address generator for storing a current read address; a read address increment control; wherein the read address increment control sets the future read address based on the difference between the write address and the current read address. Another method of driving a numerically controlled oscillator includes providing a local clock with a clock cycle; generating a numerical value during each clock cycle; adding the numerical value to an accumulator having a most significant bit; and using the value of the most significant bit as an oscillator. Another apparatus includes a local clock with a clock cycle; a jitter buffer having a write address and a current read address; a first accumulator; a second accumulator having a most significant bit; an increment control; wherein the increment control sets an accumulation value to be added to the first accumulator based on the difference between the write address and the current read address; wherein the value of the second accumulator depends on the first accumulator; and wherein the most significant bit functions as an oscillator.