If you view streaming content in Adobe Flash Player, you experience latency when pausing and resuming video playback.
This issue occurs with versions of Adobe Flash Player earlier than Flash Player 9 Update 3 (build 22.214.171.124). When you pause video streaming from Adobe Flash Media Server, Adobe Flash Player sends pause event (NetStream.Pause.Notify) to Flash Media Server. The Flash Media Server buffer is then cleared, causing playback to stop while the player rebuffers data. The latency between the rebuffer start and the resumed playback can be a long time for low-bandwidth viewers. This experience is typically less of an issue for HD (high-resolution 1080p) content viewers.
Upgrade to Flash Media Server 3.0 and Flash Player Update 3 (build 126.96.36.199) to utilize the Smart Pause feature.
Smart Pause does not clear the buffer during pause and unpause events. Therefore, the player can reuse its current buffer instead of downloading it again. The player pauses (NetStream.pause()) the playback but SmartPause allows it to continue receiving data until the buffer limit is reached. This process allows playback to begin almost immediately at unpause because the player doesn't have to refill the buffer up to the limit.
Once the buffer limit is reached, Flash Player sends the pause event to Flash Media Server. The buffer limit per pause event is the greater of NetStream.bufferTime or 60 seconds. For example, if NetStream.bufferTime is 25 seconds, Flash Player continues buffering until NetStream.bufferLength is 60 (because 60 is greater than NetStream.bufferTime(25)*2 or 50 seconds).
Flash Player flushes the buffer (set NetStream.bufferLength to 0) if any single pause event increases the value of NetStream.bufferLength more than 600 seconds or the value of NetStream.bufferTime*2, whichever number is greater.
For example, if NetStream.bufferTime is 250 seconds, Flash Player flushes the buffer when NetStream.bufferLength reaches 600 seconds; if NetStream.bufferTime is 360 seconds, Flash Player flushes the buffer when netStream.bufferLength reaches 720 seconds (or NetStream.bufferTime (250)*2).
Smart Pause is enabled in Flash Media Server 3.0 by default and is retro-compatible with existing applications. However, Flash Player Update3 (188.8.131.52) is required to take advantage of this feature.