User Manual

Limitations and known issues
This section includes known issues or limitations that affect functionality or usability and ways that you can work
around these limitations.
Affecting encoding
l Limitation: When Pearl-2 is overloaded, video frames or audio samples can be dropped causing variable frame
rate and audio cracks.
Workaround: Pearl-2 is a powerful system capable of many simultaneous tasks, but like any other computing
device, it has finite resources. If this problem is observed, check the CPU load from your system's Info page.
To reduce system load, do any of the following:disconnect unused video displays from Pearl-2's video output
ports, delete unused channels and unused layouts, or reduce the complexity of layouts by scaling at the source
instead of having the system scale, or reduce the number of sources in layouts, or reduce the frame size or
frame rate for channels displayed on the video output ports. Note that actions performed in the Admin panel
and Epiphan Live can increase overhead (such as adding channels/sources to Epiphan Live's Dashboard preview
panels), as can switching layouts via Pearl-2's touch screen.
l Encoding video at 60 fps with either 16 kHz or 22 kHz AAC audio can result in some dropped video frames.
Workaround: Select another video frame rate, a different audio sampling rate, or choose MP3 audio.
l Configuring very low frame rates such as 1 fps encoding with a high bitrate setting (e.g. 7000 kbps) results in
poor video quality.
Workaround: Allow Pearl-2 to automatically select the best bitrate setting. For 1 fps, this results in a bitrate of
about 1180 kbps.
l Occasionally, a solid black image appears when connecting an AV.io HD capture card to a USB port on Pearl-2.
Workaround: Reconnecting the capture card resolves the issue and captures the video normally.
l Some audio distortion is heard on video output port using PCM 22 kHz encoding or very low frame rate(1-5
fps).
Workaround: For best results, use AAC 48 kHz or PCM 48 kHz audio encoding and encode the channel at
higher than 5 frames per second.
Affecting streaming and recording
l Streaming status on the touch screen does not include Wowza Streaming Cloud transcoder settings.
Workaround:Start the transcoder from the Pearl-2 or Wowza web UI.
l Interlaced SDI capture is sometimes shifted downwards, resulting in a small green line at the top of the video.
Workaround: This issue varies with different sources. If it is affecting your capture, the best solution is to crop
out the green line in your layout.
l During recording if the touchscreen is used to switch layouts, headphones attached to the audio jack on the
front of Pearl-2 sometimes pick up audio crackling and pops during the switching process.
Workaround: Note that these artifacts do not affect the final recording, only the audio monitoring feature. To
avoid the disruption to audio confidence monitoring, use the Pearl-2 Admin Panel or Epiphan Live to switch
between layouts.