epiphan Networked VGA Grid, User Manual, Page: 370 / 387

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.
Important notes about upgrading from firmwares older than 3.16.0
1. In release 3.16.0, configuration presets replaced the concept of backup files. These new files use a new format
to accommodate portability between systems. As a result, backup files from previous versions (prior to 3.16.0)
cannot be loaded on systems running firmware 3.16.0 or newer. Further, if upgrading from a release older than
3.16.0, all existing configuration presets are deleted during the firmware upgrade. Be sure to keep notes for
any configuration presets you wish to recreate.
2. As of release 3.16.0, streaming can be enabled and disabled independently from streaming credential
configuration. If upgrading from a release older than 3.16.0, streaming defaults to enabled (started) until set to
disabled.
Affecting encoding
l
Limitation : When audio is enabled on an SDI source where video is already being captured, it takes up to 15
seconds for the system to detect the audio. Once detected, the audio is properly synchronized with the video.
Workaround : Start the SDI signal with audio enabled, or check to ensure audio is detected before streaming or
recording.
l
Encoding with MPEG-4 sometimes results in poor quality.
Workaround : From the channel's stream setup, increase the video bitrate to improve picture quality.
l
Video bitrate for MJPEG streams is larger than the configured value.
Workaround : Verify the actual bitrate on the channel's channel status page when there are connected viewers.
If lower bitrates are important, select another codec.
l
For VGA sources only, some wide-mode resolutions are not correctly identified and result in a slightly squished
image (e.g. for a 1360x768 source, the detected resolution may be 1024x768).
Workaround : This issue is related to the video source. Test your source to see if it exhibits the issue. If
possible, avoid using wide-mode for VGA sources that exhibit this issue.
l
When changing a channel's source from a local encoder source to an external encoder source, it's possible to
have an AAC audio encoding bitrate that is higher than the VGA Grid HD Encoder supports. The resulting
stream or recording may be unplayable and you may encounter a warning about variable audio bitrate.
Workaround : When changing from local to external sources, delete the channel rather than changing the
source(s). Or, if re-using channels, ensure audio encoding bitrate for VGA Grid HD Encoders is set to no more
than 160 kbps.
l
Recordings made with encoded streams from VGA Grid HD Encoders, using AAC audio and AVI file format are
not playable via VLC.
Workaround : Use another media player, such as Windows Media Player; choose a different audio codec; or
save recordings as .MP4 or .MOV files.
l
The automatically calculated frame size for HD VGA sources is occasionally incorrect.
Workaround : This problem is caused due to cable degradation or poor cable connection. Re-seat or exchange