Gallery View
Previous versions of Lync leveraged
active-speaker video switching, which meant that users would see a
video stream only for the current speaker, and Lync would dynamically
switch the video feed to another user when it detected that someone
else was speaking. This meant that all users received the exact same
video stream from the A/V MCU and there was no control over the layout
or appearance. The user who was currently speaking would continue to
receive the video stream for the user previously considered active.
Lync 2013 has introduced the new Gallery View option, shown in Figure 1,
which displays up to five concurrent video streams while in a
conference. These streams are displayed in a single-row, side-by-side
horizontal orientation within the conference window. Since some
meetings will exceed five participants, Lync displays the photo for
each additional user in a row below the gallery video streams. Similar
to active-speaker switching, users will move in and out of the five
video streams as they speak. A user can also “pin” another user’s video
stream to his gallery so that the pinned user’s video stream will
always be visible to him. If a user is not providing a video stream, a
static photo is displayed in its place.
Figure 1. Gallery View.
Active-speaker switching hasn’t been removed
from the product, but Gallery View is instead a new option available to
administrators and users. While in a conference, users can actually use
the new Gallery View, or switch back to the traditional active-speaker
switching mode, which Lync calls Speaker View. These changes are unique
to each user so there can be a mix of users within the conference using
both Gallery View and active-speaker switching.
Each user has a level of control and
flexibility over the layout in addition to the type of video stream. In
addition to switching between Gallery View and Speaker View, a
conference participant can enable Presentation View to hide all video
streams and view only the current shared content. This can be useful on
small portable screens since the video streams have been moved into the
same window as shared content instead of the old side-by-side
view. The last option available to users is the Compact View, which
simply displays the static photo tiles of each participant along with
the meeting content.
The addition of Gallery View
natively within the product is a huge advantage to organizations
because this was a feature previously provided only by third-party
partner MCU solutions.
HD Video Conferencing
Lync was historically very limited in terms
of video resolution for peer-to-peer calls and especially within any
conferences. Office Communications Server 2007 R2 was limited to CIF
quality 352×288 resolution for conferencing, and Lync Server 2010
allowed only up to VGA quality 640×480 for any conferences. These
resolutions were perfectly acceptable for meetings exclusively
involving workstation webcams and small screens, but as screen sizes
have grown and webcam quality has improved, these resolutions were
inadequate in a full-screen mode. These low conference resolutions
looked especially poor on large HD television screens used by
room-based video systems.
Lync Server 2013 has thankfully added support
for both 720p (1280×720) and 1080p (1920×1080) HD video conferencing
within the A/V MCU. Again, businesses were previously forced to
leverage expensive third-party MCU hardware or software to take
advantage of these resolutions in older product versions, so this is a
very welcome addition.
H.264 Codec
The capability to support HD video
conferencing resolutions and multiple video streams within the Gallery
View is driven by Microsoft switching from the proprietary RTVideo
codec to the more commonly used H.264 video codec.
The H.264 codec used by Lync 2013 supports
Scalable Video Coding (SVC), which allows the server to provide unique
streams to endpoints depending on their capabilities. For example,
based on the same source stream, the A/V MCU can deliver a
lower-resolution stream to a small tablet, deliver a medium-quality
stream to a desktop, and still provide a 1080p stream to a room system.
The shift also enables clients to
leverage GPU hardware for encoding and decoding, which means the
processor requirements for client workstations have also been reduced.
Instead of requiring a quad-core processor to send HD video, clients
now need only a dual-core processor to send HD and a single-core
processor to receive HD video. This helps reduce strain on the A/V MCU,
which had previously required a significant amount of processor
resources to mix and distribute a single RTVideo stream to endpoints.
H.264 can also deliver HD video streams at lower bandwidth levels than
RTVideo required, so organizations can support more HD video calls.
Lync Web App Audio and Video
Another weakness in the previous versions of
the product was the fact that a thick client was required for anonymous
participants to join any audio or video on their endpoint to the
meeting. This requirement often caused confusion for participants using
Lync Web App because content-sharing features were
available, but audio required PSTN dial-in and video couldn’t be
shared. Users could optionally install the Lync Attendee client to use
IP audio and video from their workstation, but this was an extra step
and never proved to be as popular as the old Live Meeting client.
Lync Server 2013 has rectified this situation
by providing IP audio and video within Lync Web App through a
browser-based plugin. This change provides anonymous users with a
single option for joining conferences with all the functionality that
could possibly be used, including the new Gallery View for video
conferencing.
The newly revamped Lync Web App no
longer uses Microsoft Silverlight and is instead based on HTML and
JavaScript standards, although it is not entirely HTML5. Audio, video,
and screen sharing capabilities are provided through a small plugin
installed while the user joins a meeting. The plugin requires no
administrative privileges and works on both PCs and Mac platforms, but
there is no support for Linux browsers today.
Smart Cropping
The streams displayed in Gallery View are all
a square aspect ratio instead of any VGA or HD resolution provided by
the user’s webcam. Lync uses a new feature called Smart Cropping, which
locates the user’s face within the video stream and centers a square
crop around the face, removing any extra space in the video around the
actual person. This is to ensure that both streams have a similar size
and resolution while they are viewed in the side-by-side Gallery View.
The feature is dynamic so if a user shifts positions within her seat,
the smart crop will follow the user’s face and adjust to ensure that
she is still centered in the video stream.
The original release of Lync 2013
always cropped the user in meetings, but a later update added the
option for users to control the cropping behavior. Lync Server 2013 has
logic to detect if the source device is a Polycom CX5000, previously
known as the Microsoft Roundtable, and automatically use a widescreen
format, but basic webcams don’t provide this logic.
