A visit to the XVision Display at IFSEC 2014
Reminder: I had 5 questions specifically relating to the exporting of evidential video from a Video Surveillance System.
I originally chose the new XRN 1609 Network Video Recorder (NVR). However, upon using a mouse to control the input AND having a USB Data storage device attached, the mouse would freeze. When the USB device was removed the mouse would spring back to life! As a result of this little technical oversight, I moved onto something else.
Next up was the X400R. This seemed to work with both storage and mouse connected!! It was of a similar compact size to the original NVR and again is the sort of device you would find in small to medium businesses or homes.
How easy is it to export evidential video from this device?
Navigation around the NVR’s interface was simple as I have seen it many times before on other rebrands. I have never understood though, and this goes for ALL manufacturers, why is it that nothing happens when you insert a USB device into the device. Why would anyone insert a USB device into a recorder? That’s right – to export evidential material. So why doesn’t the export dialogue box appear automatically?
After I had selected my time period and cameras, my export was completed quickly. I am sure that there was another option for export. As a result, and whilst writing this report I searched for the on-line manual to confirm.
The XVision site only had the data sheet. I found the manual here:
I could not find anything in the .pdf manual specific to the retrieval of video evidence.
How easy is it for me to play the exported footage?
Anyone dealing with video from surveillance systems over the past few years will recognise the play.exe icon, the file list and the .dav’s. It’s the .dav files that contain our exported video material. For the newbie, it wouldn’t take much working out – double click the program that says PLAY! It’s one of the reasons why I quite like the export format – it’s simple. For basic playback, why over complicate matters.
Upon selecting the ‘play’ application I found the first issue – and one that I have come across before!
The software was in spanish!
Rather than head for google translate, this is a simple case of changing some of the software configuration settings. If you look above at the exported file list you will see player.ini
This is the instruction file for the player and within it is a language control. You just need to change this from ‘spa’ to ‘eng’ (or whatever you require!)
Once this is done, navigation around the GUI is much simpler for non Spanish speaking persons, and playback is possible! The language issue is not just down to the device being a ‘show’ model. I have had this on a number players over the years. Usually when they are purchased from well known auction sites and then imported!
OK, we can play something now…
The GUI gives a fair bit of functionality and I can play through my video files easily. The only missing component on playback is some form of multi camera support. The ability to playback a number of windows at the same time etc. would be great.
How easy is it to analyse and understand the format of the video?
As can be seen from the image above, we do get some information on the file being played back. All of this is great and it helps during the analysis of the video data. It doesn’t tell me the format, frame type, GOP etc but it’s a start!
What about the information we are given though – is it reliable?
It’s saying 15 FPS with a duration of 5mins and 57 secs. This equates to 357 seconds. Multiply that by 15 (FPS) equals 5355. Ok, so why does the player only report 5339? Where have 16 frames gone? May have to come back to that!
The player does have a lot of functionality though and is really ‘light’, meaning that it runs very easily on most PC’s.
Are there any functions to deal with the evidential video within the software?
This is a common problem with this type of player. Although there is a button for placing the .dav video into an .avi container, it is not live. The developer has decided not to include this functionality with their version of the software. Some versions of this player have this included and it makes the process of preparing demonstrative video much easier. The Save Image function gives an uncompressed .bmp image. This is much better than a re-compressed jpeg. It also retains the original pixel dimensions.
Is it possible to deal with the evidential video away from the software?
Luckily, again – the answer is yes! The H264 format has not strayed too far away from the standard so its relatively easy to analyze and then contain the video data within a video wrapper. Obviously, if the developer had included the function in the first place, we wouldnt need to do this manually! The timing information of each frame is also retained so 15 frames does equal 1 second. (Identified in FFprobe). Whilst conducting the probe, I searched for missing coded pictures..
Upon viewing the original and the re-wrap, I could see stuttering and also duplicate frames at those points. Strangely though the GOP structure stayed at 15. Further testing would be required to establish when the drop occurred. Was it during the original capture, or during the export from DVR to USB. Also, the footage did not begin or end exactly at the seconds. This is due to the export starting at an I frame rather than at the second. All of this would possibly explain why I have 16 frames missing. A lot of testing is therefore required if some of these details are important.
1. I have no idea if the problem with the first NVR (mouse freeze when USB inserted), was down to a fault with the machine or my USB device. I have seen this before though when both devices are powered and controlled by the same interface. The USB flash pen drive has never been rejected before and has worked flawlessly ever since. It even worked on the NVR discussed in this article. Whatever it was, it does highlight that USB devices should be universal and if the device can be controlled with a mouse then it must be able to export to USB at the same time!
2. A lot of small, international software packages have multi-lingual support and this is asked when first run. If a manufacturer is selling worldwide then a simple ‘Language’ dropdown may be useful when the software is first run.
3. MILLISECONDS / FRAME NUMBER. Actions, movements and speed require individual frame analysis. If the information provided is questionable, this takes a lot of work to establish exactly what is going on. Adding this information is of high importance
4. The dead AVI button. Placing footage into a container for easy processing for demonstrative work is one of the most common tasks of any Forensic Video Technician. Not including the functionality becomes frustrating. If that capability is included with more sophisticated software, and this is downloadable, then there should be a web link for it. Remember – it should wrap – NOT Transcode!
5. Missing images. This is a big one. If frames are dropped during the initial capture into the NVR then this should be clearly seen, perhaps a blank image. If frames are dropped during the export onto USB device – the person conducting the export needs notifying and a text file created detailing how many frames were dropped.
6. No multi-camera support. This would be a great addition for those companies using the .dav export format.
As said earlier, I do like the format and player – its simple and light but the player does also have a lot of functionality (far more than I could go into here). With a few tweaks it could be really useful.
The information provided here, has been supplied to assist the video security business.
If anyone from XVision wants to improve the systems using the information provided, please feel free to get in touch.