DASH – short for “Dynamic Adaptive Streaming over HTTP” – is a streaming protocol that uses adaptive bitrate streaming for distributing high-quality media content via the Internet. Similar to HLS, DASH splits a large video file into many small sections. These usually are slightly shorter than the HLS standard of 10 seconds, namely only 2 – 4 seconds. So a fast change is possible when the internet connection gets lower or better. DASH is more modern than HLS but is not compatible with iOS devices.
HLS and DASH have a few commonalities. They are both entirely based on HTTP, and both split the video data into segments, which enables adaptive bitrate streaming. But there are a few differences:
Encoding: MPEG-DASH allows the use of any encoding standard. HLS, on the other hand, requires the use of a specific one.
Device support: HLS is the only format supported by Apple devices. iPhones, MacBooks, and other Apple products cannot play videos delivered via DASH.
Segmentation: DASH typically segments video for delivery into smaller segments than HLS. The default segment length for HLS is 10 seconds, DASH segments generally are 2 to 4 seconds long. This means that DASH allows faster switching between quality levels to adapt more quickly to network conditions.
Standardization: DASH is an international standard. HLS was developed by Apple and was not published as an international standard, although it has broad support.
HTML5 support: HLS is automatically supported by HTML5, but DASH is not. This means that some browsers or apps cannot play MPEG-DASH video streams, even on non-Apple devices.