GV FAE Knowledge

Article ID: GV15-10-03-19
Released Date: 03/19/2010



Applied to
GV-1120A / 1240A / 1480A

What are GV-Combo Cards and GV-Combo A Cards?
GV-Combo Cards are GV-1120, GV-1240 and GV-1480 of version 1.02, 1.10, 2.00 and 2.01.
GV-Combo A Cards are GV-1120A, GV-1240A and GV-1480A of version 3.1, 4.2 and 4.21.

Are GV-Combo Cards and GV-Combo A Cards the same?
No. In terms of cardboard design, GV-Combo Cards and GV-Combo A Cards are different in the card layout and driver. In terms of recording performance, GV-Combo A Cards have higher frame rate in most of VGA, D1, Half VGA and Half D1 resolutions than GV-Combo Cards.

The two different drivers that you can find in Windows Device Manager are listed below. Make sure you install the correct driver for your GV-Video Capture Card; otherwise the video capture card cannot work properly.
What is the performance comparison between GV-Combo Cards and GV-Combo A Cards?
Compared to GV-Combo Cards, GV-Combo A Cards provide higher frame rate performance in most of VGA, D1, Half VGA and Half D1 resolutions. Up to two-fold increase in frame rate is possible when using GV-Combo A Cards.

In addition to higher frame rate, GV-Combo A Cards feature Turbo Mode which allows recording at the high speed at VGA and D1 resolutions.

Comparison 1:
The following is a frame rate comparison of GV-Combo Cards and GV-Combo A Cards in different resolutions based on MPEG-4 (ASP) codec.

Single Card :Codec: MPEG-4 (ASP)
Dual Card :Codec: MPEG-4 (ASP)
Comparison 2:
The following tables are another testing result of comparison between GV-Combo Cards (GV-1480 X 2) and GV-Combo A Cards (GV-1240A X 2). Previously you need to use 2 GV-1480 Cards to reach the expected frame rate at VGA, D1, Half VGA and Half D1 resolutions. Now 2 GV-1240A Cards can achieve the same frame rate as 2 GV-1480 Cards with similar CPU usage.
How about CPU usage with identical and non-identical videos?
Under a testing environment, you may connect multiple channels of identical videos to the GV-Combo A Cards. In this case, the CPU usage could increase by 7% on average during recording due to high motion scenes simultaneously occurred on all channels. However, each video capture card is no exception in consuming more CPU usage when high motion or complex scenes occur on all channels exactly at the same time. And in a real surveillance environment, video images will not be identical and the occurrence of high motion scenes on all channels is temporary not continuing. Therefore, in terms of non-identical or live video images, the CPU usage is the same between GV-Combo Cards and GV-Combo A Cards. It is highly suggested to use non-identical or live images for your testing.

What is GV-Combo A Cards performance in a different codec?
No matter which GV-Video Capture Card you use, its recording performance varies among compression codecs. That is because each codec has a different compression speed and size which are intended for different applications and purposes. However, remember the general rule that use of better codec means increasing workload of CPU and the frame rate may also be influenced.

Comparison 1:
MPEG-4, MPEG-4 (ASP), H.264 and H.264 V2 are four types of codec used by the GV-DVR / NVR. The following is a comparison for these four codecs.
Based on different codec properties mentioned above, if you set the codec to be H.264 or H.264 V2 for GV-Combo A Cards, the expected frame rate may not be achieved due to low compression speed and high CPU loading but you will get much smaller file size than using MPEG-4.

Comparison 2:
The following is another test result of file size and CPU usage with different codec applications on GV-1480A. According to the rule that better codec means higher CPU usage and smaller file size, H.264 V2 has the highest CPU usage (76% ~ 85%) and smallest file size (197.1 MB) at Half D1 resolution.
Conclusion
GV-Combo A Cards not only have better recording performance than GV-Combo Cards, but also feature Turbo Mode. Because of higher frame rate, GV-Combo A Cards require more powerful CPU capability or PC specifications. There is no exception for every video capture card in higher CPU usage when you apply identical video images with high motion scenes simultaneously or use better compression codec.