NetPlay Video FAQ:
|I am using centralized rack mounted audio. How do I set my audio delay to acheive the best AV sync (lip sync matching)?||You will need to use an audio switch with programmable audio delay such as our CMX-A2 DSP audio matrices. The total end to end video latency is currently 995ms in mpegts mode and 600ms in rtsp mode on typical networks with a typical TV. This corresponds to an input delay setting of 240 or 170 and an output delay setting of 4 (default) on CMX-A2. You can fine tune this using a lip sync test pattern (digital video essential or other DVD). However, in most cases just using these default values is a close match.|
|I am using the audio out of VRX. How do I set my audio delay to acheive the best AV sync?||The VRX is automatically adjusts for ideal AV sync, including the TV latency. Some TVs do not provide their latency information via the HDMI port, so in those cases we use a default value. If desired, you can fine tune AVSync by adjusting the audio delay in Virtual Matrix sink setup form. Note that this delay does not change in real time, you must switch away from the source and back after making an adjustment.|
|I am using audio return channel from VRX back to NAB100. How do I set my audio delay to acheive the best AV sync?||NetPlay automatically configures this path for minimum delay. On most networks, this latency is <20 ms and thus less than the video delay of the TV. No adjustment is needed, but you can fine tune the audio output delay on CMX-A2/NAB is desired.|
|The ARC audio from VRX to NAB100 sometimes has audio glitches. How can this be resolved?||Make sure the background application on the VRX is set to Digital Signage. XBMC or cMatrix can cause buffer underflows.|
|When I first switch to a new source, I see a little picture jutter or AV sync is slightly off for a few seconds.||NetPlay video uses several real time algorithms to match the TVs display rate and maintain a fixed end to end latency. These algorithms gather data for several seconds after the stream starts, then make small adjustments to push all parameters into perfect alignment. These adjustments are very small and cannot be seen in nearly all cases, and the system should be in perfect alignment within 30 seconds.|
|I am switching to a source I know is on, but the VRX is not displaying the video.||Your source may have changed format drastically.
Usually VRX will detect the saved format profile is wrong and
regenerated it. However, if the detection fails you may need to
manually delete the profile in the Virtual Matrix source config page
(use the "reset" button). If this occurs again, you can either
turn profiling OFF for that source (slower switching) or the preferred
method would be to force the source stream resolution to a fixed
resolution (resolution control box). |
This can also happen if your display does not support HDCP. Use the display config menu to check if HDCP is present and enabled (turn debug OSD on).
|How should I configure my Blu-ray player for the best picture?||Most Blu-ray and DVD movies are mastered at 24Hz. In the player menu, make sure you ENABLE 24hz output mode (set to ON or AUTO). Our encoders and decoders will track the actual frame rate and also set the TV to 24Hz mode if supported.|
|Sometimes when I switch to a source, it will take longer to switch.||This can happen if profiling is turned off on that
source. The decoder must detect all the stream properties every
time you switch, so it can take up to 5 seconds. Correct this by
turning profiling ON if practical. |
This can happen when profiling is turned off if the source has changed format or it is the first time that VRX has tuned that source. This is auto correcting, since the next time you switch it will be fast.
|Sometimes I lose picture momentarily or get temporary artifacts in the image.||This can happen if you have significant packet loss
on your network. Wired local networks should almost never see this
unless you have defective devices. Wireless networks can show this
if/when inteference is present. |
This can also happen if your source changes frame rate or stops sending video briefly. Blu-ray players can do this when switching between the menu (60Hz) and the movie (24Hz). NetPlay video will track this change with a brief disruption while we change the TV format. Setting the VRX to a fixed format or the source to not output 24Hz will prevent this, but it is not recommended because 24Hz video is the best quality when available.
|When I enabled multicast, my wireless network becomes slow or crashes||Your network is allowing the multicast video data to be transmitted on your wireless network. Most wireless networks cannot handle full resolution NetPlay streams and will be overtaxed. You need to filter the unregistered multicast data on the ports which go to your wireless routers. Please see Network setup (NetPlay system)|
|I do not receive audio on some sources||Future software updates will enable simultaneous encoded/multichannel audio and pcm/stereo audio. However, currently your sources should be set to PCM.|
|I can't play mpeg2 video files||Mpeg2 playback requires an additional low cost license. Select the mpeg2 license when ordering, or contact Video Storm. Note that all live video from VTX100 is h.264 and does not need this license.|
|In XBMC, I get stuttering on Blu-ray videos||First, make sure your video source is a nfs:// linked
source in XBMC. Do not use a mapped drive path (/mnt/nfs) since
this will not have the proper network buffering (treats it as a local
Second, make sure your video file has an appropriate audio track. If your TV/AVR does not support Dolby/DTS, the file should have a 2 channel audio track.
|When using mobile streaming to watch video, the video is jerky or has artifacts.||First verify that your device is powerful enough to
decode real time h.264 video. In general, your mobile device
should not be more than 2 years old.
Second, if your wireless network has too much interference it can create picture artifacts. Try switching the channel it uses or testing for packet loss performance.
|When I tune a camera stream using virtual matrix, sometimes the camera picture contains artifacts at the start||You can add --nodrop,--noseek to the custom arguments for that source in the sources setup to resolve this problem. You can also turn off profiling to see if that improves performance.|
|My video wall has synchronization delays between screens||First make sure that all your TVs have the same
options selected in the TV menus. Some options affect TV latency,
so they must be the same. The TVs should also all be the same
model for best performance. |
Next make sure all the VRX devices in the video wall are set to AUTO format mode. Using manual mode will disable parts of the sync algorithm. Finally, verify that your sources are set to mpegts mode (in vm source config).
|I am using nVidia Shield and the audio volume is very low||In shield settings => display/audio => set "Fixed Volume" mode on. This will instruct the shield to not attentuate the audio output.|