Q-See QCN 7001b Continuous Capture
  • Greetings,
    I've been running this camera for about 12 hours and I've notice something odd. At first the files were about 1mb a minute and CPU use was near 50%, after 12 hours the files are nearly 3.5 mb per minute and CPU use is 92%.
    Is this to be expected?

  • Hi Juan, my guess is that the frame rate has increased for some reason (maybe the computer or network became free of other tasks, leaving more resources available for the camera). Check the captured files to see what frame rate they have (open them in QuickTime Player and use the "Show Movie Inspector" option in the Window menu).

    If you want a consistent frame rate (say 10fps, which is good for video surveillance), then you should be able to set this in the camera's settings pages. In general you should set the camera to the frame rate at which you want to capture and no higher, otherwise you are wasting CPU and bandwidth/storage on video frames you don't need.
  • Thanks Ben!

    Not only does it not maintain a consistent size, the 2 minute time segments can vary from 10 seconds to 3.5 minutes.
    I'm still in the testing phase, working from my MBP (wifi), expecting the Mini server to arrive tomorrow.

    In the Q-See software under set-up
    Code-stream type = general
    Encoding = Mode H.264 [no Option]
    Resolution = 1.3M (1280*960) [option 720P or D1]
    Frame rate (FPS) = 10 [option 1-15]
    Bit rate type = CBR [option VBR]
    Reference bit rate = 896-5120Kb/S
    Bit rate = Customized 3584 [option 896 - 5120]
    I frame interval = 20
    Watermark setting = checked
    Watermark character = DigitalCCTV

    /Substream not checked
    Securityspy camera setting
    Continuous Capture sellcted
    Continuous Capture =checked
    Capture frequency = 1 second between frames
    Create new movie - every 2 minutes
    /Motion Capture not cheched
    Quicktime inspector
    2 files
    # 1
    Format: H.264, 1280x960 million
    FPS: 1.00
    Data size: 1.5 (1.59 min)
    Data rate: 103.43 kbit/s
    Current size 1038 x 778 pixels

    # 2
    Format: H.264, 1280x960 million
    FPS: 1.00
    Data size: 2.9 (1.59 min)
    Data rate: 195.01 kbit/s
    Current size 1038 x 778 pixels
  • Hi Juan,

    For those two clips you describe, the length and fps are the same but the data rate is quite a lot different.

    While the camera may be sending CBR (constant bit rate) H.264 data, SecuritySpy's own H.264 compression is VBR (variable bit rate), so when you tell SecuritySpy to do its own H.264 encoding (which is the case here), the resulting bit rate will vary depending on what's in the scene. Differences in brightness, complexity and movement in the video stream will all significantly affect the bit rate of SecuritySpy's VBR compression.

    If you want a constant bit rate for your 1fps recordings, I would suggest the following:

    • Set the camera to 1fps via its settings pages
    • In SecuritySpy, enable the "No recompression of video data" option in the Video Device Settings window
    • If you need to add a text overlay to the video, add this in the camera itself and turn this feature off in SecuritySpy

    With these settings, SecuritySpy will capture the incoming 1fps CBR video from the camera directly to disk, which will give you want you want and will also result in the best performance and quality (better than SecuritySpy decoding and then re-encoding the video again for capture).

    Hope this helps!
  • Thanks Ben

    It's a learning curveā€¦.for sure. The compression, as it were, is similar to rasterization in Photoshop I guess. I need to get the language down. ;-)

    The compression check boxes were off and I didn't realize if I clicked on the ? mark that it would explain about overlay and compression. (I need to be more thorough)

    So I had used the overly option in the camera, but couldn't control the font size, it's like 30 points, so I went back to SS overlay. At one point both were running and the files grew to 7.8mp per minute at sundown, which seems to be the time where the files are the largest. Shadows perhaps create a lot of work for the system.

    CPU use was up to 90%, where it would normally run at 60% with Security Spy overlay, and now 42% using the cameras overlay, big difference!

    The 1FPS was a default setting in the camera's software, I don't know if there's an option, or if I should change it.

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