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StreamQ™ is a proprietary metric used by Streamcheck that is rapidly
becoming the industry standard for measuring the streaming media user experience.
StreamQ™ is measured in letter grades from A+ down to F that indicate
the amount of time a user had to wait or experience interruptions ("Frustration Time")
versus the time actually spent enjoying the content (aka "Play Time").
• StreamQ™ basics
• StreamQ™ math
• StreamQ™ examples
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StreamQ™ basics
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From the user's perspective, a high quality streaming experience requires
that playback begins quickly and proceeds without interruption.
Before playback begins, time is spent connecting to the streaming
server and buffering the content. During playback, interruptions may occur
for "re-buffering" which occurs when the bitrate drops too low.
In order to rank the experience quantitatively on this basis, Streamcheck
invented the StreamQ™ metric which is based on the time a user has to wait
for connecting, buffering and rebuffering.
Streamcheck uses a check 60-seconds in duration to represent a user experience
and hence for calculating StreamQ™. From internal analysis and comparisons,
numerous 60-second checks closely approximate an end user experience, which
may last longer than one minute.
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StreamQ™ math
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The following equations and definitions demonstrate how StreamQ™ is
assigned to each check:
• Frustration Time + Play Time = Check Time. Every second of
Check Time is either spent viewing/listening to content or waiting for the
content to arrive.
• Frustration Time = Connect Time + Buffer Time + ReBuffer
Time. Frustration time is made up of these three non-viewing activities. The
number of Rebuffer events is also recorded.
• Connect Time = Amount of time elapsed between the initial
request for data by the media player and the start of buffering. This time
includes DNS lookup and resolution, Metafile actions and resolution,
server/player handshakes and the transport of the first byte of data to the
player.
• Buffer Time = Amount of time used to build up the initial
buffer of data for the stream, based on player default settings.
• Rebuffer Time = Amount of time required to refill the
buffer for all rebuffer events. This time represents interruptions of the
viewing/listening experience. To provide a further penalty for rebuffering,
one second is added to the frustration time for each rebuffer event.
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StreamQ™ examples
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Below is a "time-profile diagram" that shows a typical successful check. The connection took
1.2 seconds to complete, followed by 3.4 seconds of buffering. The remainder of the 60 second
check (55.4 seconds) was spent playing. The total frustration time is 4.6 seconds which
translates to an A+ (since it is under 6 seconds).
This time-profile diagram shows a stream that suffered from rebuffering during playback.
Each rebuffer event adds a 1 second penalty to the overall frustration time, in addition
to the actual length of the rebuffering.
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