We have an AMI for Wowza 4.0 built on m1.xlarge (64 bit, 4 core, 15 GiB RAM) EC2 instance. It is used for On-demand Audio streaming, bit rate of which varies from 32Kbps to 64Kbps. The media files are located on S3 and have following specifications:
Format: M4a
Codec: AAC

The major issue in front of us right now is delay in starting the stream and there is no significant difference even if its a repeat request for the same content. The worst affected is the RTSP streaming in which the initial delay is around 8-10 seconds in a good connectivity (wi-fi /3g) and goes upto 18 seconds in case of slow networks (2G).

The server is tuned as per the instructions in performance tuning document and I have also got all the network restrictions checked to ensure there is no UDP blocking.

During my quest to find reason, I came across suggestions of using streaming servers which are specially designed for audio streaming applications. These servers does not add any overhead of initializing Video capabilities that are not required in case of audio streaming, which is the case with Wowza and that adds to its initial delay. Not sure how authentic this claim stands but need your opinion.

What could be the reasons of this delay and how can I decrease it.

Thanks in advance.

Best Regards,
Manoj K