Introduction
In previous article we have discussed about HLS or HTTP Live streaming protocol and its working. Now in this article we will discuss what MPEG DASH is? How it is different from HLS or advantage of MPEG DASH over HLS?
What is working of MPEG-DASH and MPEG-DASH use case.
What Is MPEG DASH
MPEG DASH stands for MPEG Dynamic Adaptive Streaming Over HTTP. MPEG DASH is adaptive streaming protocol to deliver online media in efficient way.
MPEG DASH can be called as advanced version of Adobe HDS and Apple HLS. Because it supports H.265 codec while HLS supports H.264 codec. MPEG-DASH is more efficient than HLS in terms of latency and delivery speed of media.
MPEG-DASH is designed in that manner that it is not dependent of codecs which enable it to support all codecs like H.264, H.265, VP9 and VP10 etc. MPEG-DASH uses HTTP Web server for delivery of content. It supports insertion of advertisement.
So MPEG-DASH it successor of HLS and HDS as well. It is adopting fastly. Youtube and Netflix are already using this technology. It is very useful in OTT Headend system for delivery of H.265 encoded videos which provides good quality in less bandwidth.
Directly MPEG-DASH do not support to HTML5. We needs to implement java scripts in MPEG-DASH for supporting of HTML5 which enable to play video in HTML5 supported media players online.
It also enable to play efficiently 360 degree videos live as well as pre recorded.
Working Of MPEG DASH
To understand the working of MPEG DASH there are mainly two sections of it first one is Media File TS and second one is Manifest File. The media file is encoded in MPEG 2 Transport Stream.
This encoded TS media file is known as Media Presentation. On the other hand manifest file is known as Media Presentation Description.
This manifest file have reference links of segmented media files of different data rates. So this manifest file is useful for user end devices to select streams according to its internet bandwidth.
As shown above in figure for better understanding we have customized MPEG DASH working block diagram. The media representation contains various blocks in which each block contains various segments. Each block represents a particular time period of media playing.
Media Presentation Description helps the DASH player to select which data rate stream needs to play according to internet bandwidth. Media presentation description contains all the reference URLs of media chunks.
Now these media segments goes via HTTP protocol for playing into the MPEG-DASH clients. MPEG DASH uses TCP (Transmission Control Protocol) Transport Protocol.
Conclusion
MPEG DASH is efficient adaptive streaming protocol for delivery of MPEG DASH devices. All HTTP based streaming protocol like MPEG-DASH and HLS uses HTTP web server instead of streaming server. Streaming servers are used by the Adobe HDS where RTMP protocol is used.
So supporting of HTTP Web Server for media streaming is main advantage of using HLS and MPEG-DASH.
Know More About HLS or HTTP Live Streaming
