Performance of Ethernet AVB

Table of Contents

• Introduction
• Setup Details
  • SOC Configuration
  • IEEE1722 AVB Stream Configuration
• Performance Measured
  • Latency Measured
  • Media Clock Sync
• See Also

Introduction

This section provides an overview of Ethernet Audio Video Bridging (eAVB) performance benchmarking on AM275 EVM. The benchmarking evaluates the latency of audio transported over ethernet.

Setup Details

The Ethernet AVB Audio Playback Demo is used to obtain the performance numbers.

SOC Configuration

SOC Details	Values
Core	R5F0 Core 0
Core Operating Speed	1000 MHz
Memory Type	MSRAM
Cache status	Enabled
EVM Type	AM275-EVM
Packet buffer memory	MSRAM (Cached)
Ethernet Link	RGMII at 1 Gbps

IEEE1722 AVB Stream Configuration

Parameter	Description
Number of Channels	8
IEEE1722 AVTP Subtype	AAF PCM
Sampling Rate (Media Clock Freq)	48 kHz
Bit Depth	32 bits
Samples Per AVTPDU	6 Samples
IEEE1722 AVTP Packet Length	247 Bytes
IEEE1722 AVTP Frame Transmit Interval	125 µs
McASP Transaction Size	16 Samples
McASP Transaction rate	3000 Hz (333.3 µs)

Performance Measured

Below is the Setup Details

Latency Measured

Parameter	Min Latency (µs)	Max Latency (µs)
AVB Latency (A)	16	37
McASP - McASP Latency (B)	-	332*
Jack - Jack Latency (C)	-	1270*

* This performance is benchmarked when the McASP Transaction size is 6 Samples.

Media Clock Sync

DP83TG721 is used as Audio clock generator, IEEE1722 CRF stream is used to recover the media Clock. The Built in CRF Slave Functionality of the DP83TG721 is not used.

Parameter	Value
Maximum Absolute Phase Difference	200ns*

* - Futher optimization is possible by tuning the control loop parameters.

For More details, refer to Ethernet AVB Multistream Media Clock Recovery

See Also