Manufacturer's Response - ZTE ZXT500
Manufacturer's comments supplied by Review Video on behalf of ZTE.
- (Page 1) To enable connection of an H.239 (second video stream) XGA or video source an optional V-Box is required. Setting up this unit required an external stand alone Switch/Hub together with a PC. The process was complex and without adequate documentation took about 40 minutes.
Response: Version T06 of software which is the version supplied for evaluation allows the VBOX to be connected directly to the back of the Codec via an HDMI to HDMI style cable. Cables were not available at the time of the units shipping for evaluation. It does simplify the installation and keeps it in line with competitors products in this regard. - (Page 2) At calls of 1Mbit/s and above the ZXT500 is capable of delivering 4CIF resolution at 25 frames per second. Above 1 Mbit/s with video negotiation set to auto, H.264 and iCIF are selected.
Response: We have replicated this in our own labs. I have raised this with R&D in China. Im awaiting their response as to why it negotiates iCIF rather than 4CIF. - (Page 3) A very fast zoom speed made fine adjustments to picture framing difficult.
Response: This has already been noted. A variable zoom speed i.e. fast at minimum zoom graduating to slower as maximum is reached will be implemented in the upcoming software release. - (Page 3) The V-Box effectively acts as a secondary CODEC to encode the input signals and transmit them across the network to the local CODEC for onward transmission to the far end CODEC. This multiple signal processing noticeably degrades the quality of the XGA I/P signal and also inflicts additional latency (time lag) making it awkward to use as a local source display when using XGA images. Composite video and audio outputs are also available on the V-Box, when content is not being transmitted a system information page is displayed that changes to content when an XGA or video source is selected. We found that this display of system information when content was not being transmitted to be distracting. As this XGA image is not compressed it could be used with advantage to display the preview of local images.
Response: We have replicated this in our own labs. I have raised this with R&D in China. I have no timescale for a resolution. We are awaiting HDMI type cable to test the local connection of the VBOX with a view to improvement in quality. - (Page 3) As the TV output does not include the audio from the local VCR/DVD or PC/Laptop it is not possible to monitor such audio locally, a serious disadvantage during a conference.
Response: Agreed, this will be raised with R&D in China to see if it can be added as a function request. - (Page 4) Conventional voice switching for the MCU was not supported in the supplied version of software and the audio control menu could not be selected.
Response: This will be implemented in the upcoming software release. - (Page 4) In Discussion mode, all sites see a split screen. If there are more than four sites, one manually selectable site fills the larger part of the screen with the others images surrounding it. If voice switching was available, the picture changeover could be automatic so that this manual switching would be unnecessary.
Response: Agreed. - (Page 4) During conferences, there is no graphical indication that the call is encrypted.
Response: I have added this as a feature request with ZTE China. - (Page 6) Standby mode was not operational on the units supplied for evaluation.
Response: Agreed, it will be functional in the upcoming software release. - (Page 7) The system may be set to auto-answer, but as it is not possible to set the microphone to automatically mute when an incoming call is detected, the participants in a videoconference may not be aware that a connection has been made and it poses a potential security risk.
Response: Agreed, it will be functional in the upcoming software release. - (Page 7) If auto-answer is not selected, an on screen message indicates that there is an incoming call but no audio alarm accompanies it, although the menu structure indicates that an audio alert should be heard.
Response: Agreed, it will be functional in the upcoming software release. - (Page 7) Only video sources connected directly to the CODEC may occupy the main video channel and only sources connected to the V-Box can be transmitted on the second video channel.
Response: This is a current design issue and will be looked at for future software versions. - (Page 7) Switching between the XGA and composite video inputs on the V-Box cannot be achieved manually. An operator has to log onto the V-Box via a web browser in administrator mode, a cumbersome and impractical method. If the unit connects to a CODEC that does not support H.239 then the V-Box inputs are inoperative.
Response: We have discovered both these during our testing of T-06 code and both have been reported to R&D in China. We await their response to these issues. - (Page 7)
Establishing conferences to other CODECS had mixed success:
- An H.239 conference to a Tandberg 990 MXP was satisfactory
- To a Polycom VSX 8000 blue screens were displayed in place of the content
- With a Tandberg 6000 B version CODEC no content was transmitted and the content screen was blank
- (Page 8) Given the complexity of the menu and the number of available options controlling an MCU conference may be challenging for an occasional user.
Response: Understood, we hope to have the programmable hot keys available in an upcoming release. It will be possible to assign commonly used system functions to these. Hopefully some of the menu functions can be assigned to these making the unit simpler to operate. - (Page 8) ...Web snapshots of send and receive images are not available via the web browser with this CODEC.
Response: Agreed. - (Page 8) While the data sheet and menu structure indicate Siren and G.722.1 protocols as being available, when these protocols were selected the negotiated protocol was G.722. In addition when G.723.1 was selected the resulting audio was unintelligible.
Response: These will be implemented in an upcoming software release. G.723.1 is intended for use in VoIP calling rather than video calling.
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