Adaptive Bitrate vs Progressive Download 2018
A few years ago we posted an article “How To Choose the Format Right for You” where we inferred that MP4 was still the safe bet and would work in all situations. While MP4 does work in all situations, it is likely not the best solution for your implementation anymore. At that time many Android devices had just recently added support for adaptive bitrates and most devices were not running the newest version of Android. Since then, Android has begun wide support of adaptive bitrates and bandwidth speeds for broadband and cellular have also increased globally. Now with the promise of 5G connectivity as well, IVA recommends using our adaptive formats wherever possible.
Advantage of Adaptive
Adaptive bitrate improves the user experience by offering the best video quality available for the screen size and connection being used. It is particularly beneficial when used in conjunction with large screens or high-resolution devices where home bandwidth is plentiful.
Adaptive bitrate videos are best for mobile implementation where connection speeds can fluctuate as a user connects from cell tower to cell tower or from WiFi to cellular data and back. IVA provides mobile bitrates on the lower end (182 Kbps – 414 Kbps) in the same manifest file. One feature of IVA’s Video API is that developers can programmatically choose the minimum and maximum bitrates they want returned. This allows for better control over the user experience across desktop, IPTV, and mobile applications.
IVA provides support for HDS, HSS, HLS, and DASH but it is clear that over the years that the industry has gravitated towards DASH and HLS.
HLS – Apple’s solution to adaptive bit-rate delivery is called HTTP Live Streaming. The source files for this format are packaged in an MPEG-2 Transport Stream which is then broken up into a series of smaller chunks (.ts files) and referenced in a .M3U8 playlist file index. Clients read the index file to request the chunks in the correct sequence. Depending on the available bandwidth, the client will choose a chunk from an appropriate bitrate allowing for seamless transitioning between bit-rates. This format is ideal for streaming video to iOS devices as it is supported natively on iOS 3.0 and later as well as Safari 4.0 or later.
DASH – Dynamic Adaptive Streaming over HTTP is the open source approach to adaptive bit-rate now in development under the auspices of the international MPEG group. The goal is to have a technology that is universally implemented compared to the more vendor-centric solutions listed above. The proposed international standard was approved in November 2011. DASH is audio/video codec agnostic, however the specification provides specific guidance and formats for use with two types of containers, the MPEG-4 file format or the MPEG-2 Transport Stream.
For more information see our Video Formats documentation or reach out to our support team with any questions.