This guide concerns buffering and latencies for Streaming Radio. Although latency is inevitable, proper buffer management allows you to optimize your broadcasts while minimizing interruptions.

Introduction

• The buffer, or buffer memory, is a small memory area that must be filled before the Player starts playing your audio stream music. It corresponds to a few seconds of sound. It is intended for greater listening comfort, to avoid small cuts in the flow being audible, which results in a jerky and unpleasant sound.
• The receiving and broadcasting servers also have buffers; real-time transmission is never instantaneous due to several technical factors:
  • The latency of 3 to 4 seconds between the generation of the sound and its reception is normal.
  • Players always buffer for at least 1 to 2 seconds before starting to play.
  • Icecast uses a default buffer of 64K bytes, equivalent to approximately 4 seconds of mp3 128k streaming.
  • Encoding clients also have buffers to avoid interruptions.
  • Reducing the buffer size can decrease latency, but this practice is risky.
  • Internet connections do not guarantee a constant throughput, so smaller buffers can cause dropouts.

Analyzing buffer stability

The diagnostic available on your Manager displays the amount of memory occupied by the buffer every second. If the stream is functioning correctly, the values should be stable:

An unstable buffer indicates either poor connection quality or line saturation. Refer to this other guide if you are looking for resolution elements.

This test is also useful for helping to detect temporary saturations of an Internet line. If the buffer is sometimes stable, sometimes unstable, this may be a sign that some users sharing the Internet line occasionally saturate the line, causing disruptions to your stream.

To verify this hypothesis, run a long-term buffer test during peak usage hours of your facilities and observe any potential disruptions.