Adaptive Jitter Buffer (AJB)

Ittiam's Adaptive Jitter Buffer (AJB) implementation enables smooth play out of audio in a packet based reception such as voice-over-packet-systems. Issues such as out-of-order arrival of packets, packet loss and variation in delays results in poor quality of audio. A jitter buffer is used to compensate for the jitter in packet arrival and out-of-order packets. An efficient adaptation scheme enables the buffer size to change dynamically in response to network conditions. The adaptation scheme can be configured for a desired level of packet drop.

The adaptation scheme and Jitter Buffer are decoupled from packet playout, allowing for flexibility in delay adjustment through various schemes such as adding/dropping pitch periods in speech, adding/inserting samples in silence periods, or adding/dropping samples at random.

Technical Specification

• Adaptation based on real time calculations of network jitter and delay
• Adapts to optimum delay automatically
• Configurable adaptation speed
• Implementation independent of the sampling rate
• Configurable for desired levels of packet drop rate and buffering delay
• Optimized implementation
• C callable APIs
• Multichannel, reentrant implementation

Applications

• Voice Over Packet networks
• Streaming Media Applications

Platforms

• Currently supported on TI C64x™ (TMS320C64xx™) and C64x+™/DaVinci™ (DM644x™)
• For further details contact mkt@ittiam.com