What is Adaptive Bitrate Streaming and why is it so difficult to measure?


watching online video

Consumers want to watch online video anywhere, anytime on any device

online video buffering

And they want the videos to be streamed without interruption or glitches in the highest resolution possible


That’s easier said than done

Video looks great when streamed at the highest resolution.
mobile phone video qoe But, when bandwidth conditions suddenly
worsen — like when going from wi-fi
coverage to the 3G network — the
demands of high resolution video can
overload a viewer’s connection.

This results in buffering and other delays that negatively affect a consumer’s quality of experience (QoE)

To address this, content delivery networks (CDNs) and video providers are turning to
adaptive bitrate (ABR) streaming technologies.

Adaptive bitrate streaming detects a user's available bandwidth in real time and calibrates the video stream accordingly, always delivering the best possible picture quality.

dyamically shifts bandwidth

ABR dynamically shifts
bandwidth to higher and lower
levels based on availability

While the concept is generally the same, there are several
different flavors of adaptive bitrate streaming technology.

Adobe
HTTP Dynamic Streaming
Microsoft
Smooth Streaming
Apple
HTTP Live Streaming



encoding

For Adaptive Bitrate Streaming to work, a video is first encoded at different bitrates to accommodate varying bandwidth connections. Each bitrate version is sliced up into tiny fragments — typically 2 to 10 seconds.

video player

The video player then pulls fragments from the different encodings and inserts them into the stream as bandwidth dictates.


This results in faster video start times
and a continuous, uninterrupted
video experience....

...which makes for happier viewers
and content providers

It also results in a major
measurement challenge, however



single video file video file fragments

Not long ago, an entire movie could
be measured as a single file.

Now, with Adaptive Bitrate Streaming, measuring
that same movie in aggregate over a large viewing
audience can require analyzing tens of thousands
of separate files.

Then consider the sheer volume of ABR files coursing
over a network with 150 channels.

network of streaming video

The number of fragment files over this network could be in the tens of millions for a single bitrate.

online video file fragments

Add several more bitrates into the equation and the number of
Adaptive Bitrate Streaming files could jump into the hundreds of millions!


This level of fragmentation turns the
measurement data into a lot of unusable noise.

measurement noise

Skytide Insight for CDNs separates the
signal from the noise by identifying,
re-aggregating and reporting on
the actual content assets.

Skytide Insight for CDNs can handle the volume and
complexity that adaptive bitrate streaming demands
and transform it into meaningful reports in minutes.