mpeg-DASH (Dynamic Adaptive Streaming over HTTP)

Mpeg Dash 类似于apple 的 HTTP live streaming(HLS),将流分片后再通过http协议将segments传给client，Mpeg-Dash则将segments以不同的bitrates编码，client根据网络的状况选择相适应的bitrates的segments.这样client可以在不同的网络环境下得到最好的播放效果。


VLC 实现了Mpeg-Dash plugin,   smooth plugin, HLS plugin,在vlc\modules\stream_filter中。

Dynamic Adaptive Streaming over HTTP (DASH), also known as MPEG-DASH, enables high quality streaming of media content over the Internet delivered from conventional HTTP web servers. Similar to Apple's HTTP Live Streaming(HLS) solution, MPEG-DASH works by breaking the content into a sequence of small HTTP-based file segments, each segment containing a short interval of playback time of a content that is potentially many hours in duration, such as a movie or the live broadcast of a sports event. The content is made available at a variety of different bit rates, i.e., alternative segments encoded at different bit rates covering aligned short intervals of play back time are made available. As the content is played back by an MPEG-DASH client, the client automatically selects from the alternatives the next segment to download and play back based on current network conditions. The client selects the segment with the highest bit rate possible that can be downloaded in time for play back without causing stalls or rebuffering events in the playback. Thus, an MPEG-DASH client can seamlessly adapt to changing network conditions, and provide high quality play back without stalls or rebuffering events.

MPEG-DASH is the first adaptive bit-rate HTTP-based streaming solution that is an international standard^[1]

MPEG-DASH leverages the already widely deployed HTTP web server infrastructure that is used for delivery of essentially all Internet content. It allows devices such as Internet connected televisions, TV set-top boxes, desktop computers, smartphones, tablets, etc. to consume multimedia content (video, TV, radio...) delivered via the Internet, coping with variable Internet receiving conditions, thanks to its adaptive streaming technology. Standardizing an adaptive streaming solution is meant to provide confidence to the market that the solution can be adopted for universal deployment, compared to similar but more vendor-centric solutions such as HLS by Apple, Smooth Streaming by Microsoft, or HDS by Adobe.