sync
The 'sync' directive controls synchronization of timestamps for segments in a DASH streaming application.
Description
In the context of the NGINX RTMP module, the 'sync' directive can be utilized to maintain consistent timestamps across media segments being served using the Dynamic Adaptive Streaming over HTTP (DASH) protocol. This ensures that playback remains in sync across different client devices as media segments are delivered, particularly critical in live streaming scenarios where latency and synchronization can impact viewer experience.
The 'sync' directive accepts a single argument which specifies the synchronization criteria. This can include settings that determine how timestamps are adjusted during fragment generation to provide a smooth playback experience. The module internally manages the adjustment of media segments based on the specified sync criteria, which can aid in aligning different tracks (e.g., audio and video) so that they playback correctly in relation to each other.
When used correctly, the 'sync' directive significantly enhances the streaming quality by reducing issues related to desynchronization, allowing seamless transitions between segments without noticeable delays or errors for the viewer. However, if misconfigured or used inappropriately, it could lead to unintended playback artifacts, such as jitter or delayed audio in multi-track streams.
Config Example
application myapp {
live on;
sync on;
dash on;
dash_fragment 4s;
dash_playlist_length 60s;
}Ensure that the 'sync' directive is compatible with other streaming settings and directives to avoid conflicts.
Be cautious when setting synchronization options for live versus on-demand streams, as behavior might differ.
Test extensively across different devices to ensure consistent playback without desynchronization.