Using MediaCache with audio streaming

Wowza Streaming Engine
1

We have been streaming mp3 (128kpbs) audio files using Wowza for some time. To date the audio files have been stored locally on the Wowza server. We have now moved all the audio files to Amazon S3 and wish to stream them from there. We are successfully streaming from S3 using MediaCache but there is a substantial delay on the initial play of any file. When streaming from local files the delay between pressing play and receiving content is 1-2 seconds but when streaming from S3 this increases to 8-10 seconds for the first play and reduces to 2-3 seconds for subsequent plays. I realise the delay is caused by the initial pull to MediaCache but is there anything we can do to reduce it?

We are using SSD so have set the write rate to 38M and the bucket size to 152M. We have tried various settings for defaultBlockSize but none seem to improve on using the default of 1M. I’m assuming the delay is greater because we are streaming audio files at 128kbps rather than video at 1mbps+. Are there any particular settings you can suggest to reduce this inital delay? Is there a way to prepopulate MediaCache? Does MediaCache retrieve the whole file before starting to stream or should it start streaming earlier? If so, how early and is this controllable?

2

You might take a look at this server listener and see if you notice any improvement:

How to preload files for the Media Cache system (MediaCachePreload)

Salvadore

3

Thanks Salvadore. Hadn’t seen this addon before. I’ll investigate and report back if it improves things.

4

Using the preloaded addon certainly improved the initial delay which reduced to 3-4 secs. I haven’t yet worked out why the initial delay is still longer than on subsequent plays after a perload but this is less important.

5

Thanks for the update and I am glad you noticed some improvement.

Salvadore