Cisco Cisco MXE 3000 (Media Experience Engine) Information Guide
Q&A
© 2008 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
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Q.
How does the Cisco MXE 3000 handle video that does not contain audio?
A.
You can use two techniques to encode video that has no audio. Some encoders support
video-only output. In the client user interface, right-click the Encoder tab, and check the Video
only option. If the format does not support video only (in the client user interface the video only
option is grayed out), you can add a silent audio track on the Preprocessor tab.
Q.
Why do video files that have no audio fail to encode by default?
A.
Video files typically have audio tracks. Failing jobs that do not have audio as a default setting
is a technique to ensure that all video has an audio track. If this behavior is not the desired
behavior, on the Preprocessor tab, Audio subtab, check the Add a Silent Audio Track box. If
an audio track is present, it will be maintained. If no audio is present, a silent audio track will
be added.
Q.
Does the frame rate of my output files have to match the frame rate of my input files?
A.
No. The Cisco MXE 3000 adds or drops frames of video as required to equal the output frame
rate requested. To ensure the smoothest possible output, video frame rates should be divided
or multiplied by even numbers.
Q.
Can the Cisco MXE 3000 convert frame rates from 25 to 29.97 fps or 29.97 to 25 fps?
A.
Yes. The Cisco MXE 3000 adds or drops frames of video as required to convert video from 25
to 29.97 fps, or conversely. Although this frame-rate method provides acceptable quality, the
conversion is not a vector-based frame-rate converter. If the video has fast-moving motion,
the picture may appear jittery.
Q.
Can I increase or decrease the frame size of my output video when compared to my
input video?
A.
Yes. Reducing the frame size of the video is a common technique used to improve perceived
video quality at lower bit rates. You can also increase the frame size from the original, but you
will see a corresponding reduction in video quality. This reduction is often acceptable if the
video content is compelling and a larger frame size is required to match the video display
method. An example is increasing the size of video captured with a cell phone to play back on
TV
Q.
Can I convert video with a 4 x 3 aspect ratio to video with a 16 x 9 aspect ratio?
A.
Yes. The Cisco MXE 3000 offers three methods to convert 4 x 3 video to 16 x 9 video. You
can add curtains (black bars are added on each side of the video) or a nonlinear stretch that
increases the width of objects that are not in the center of the video frame, or you can apply a
linear stretch that increases the width of all objects equally. You can preview the effect of each
of these options in the Preview window when creating job profiles.
Q.
Can I convert video with a 16 x 9 aspect ratio to video with a 4 x 3 aspect ratio?
A.
Yes. You can crop 16 x 9 video to remove the video on the edges of the screen to change the
aspect ratio of the video to 4 x 3. You can also letter-box the video (add black bars above and
below the video). The video has a 4 x 3 aspect ratio, but the content maintains a 16 x 9 aspect
ratio.
Video Preprocessing
Q.
What is video preprocessing?
A.
Traditional transcoding solutions produce transcoded content that is only as good in quality as
the source footage. However, when video is acquired outside studio settings, the quality of the
source footage can be less than ideal. The Cisco MXE 3000 supports a variety of