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I have a dashcam-style DVR which records video data to an SD card. The device hosts a HTTP service which allows you to configure it and download the videos.

My computer running Windows 10 has a 1 GBit Ethernet Network card, the DVR has 100 mbit Ethernet interface and the SD card is 45MB/s. They are directly connected by an Ethernet cable to create a point to point link.

When I go to the web GUI and download a video I would expect to see a maximum of 12.5MBps download, as the DVR Ethernet is the bottleneck. But I get around 3.5-4MBps.

Does anyone have any idea what would make the speed is so low? What can I do to troubleshoot this?

Cheers all,

James

EDIT: The SD card is https://www.mymemory.co.uk/kingston-128gb-sd-card-sdxc-45mb-s.html

and the DVR is https://www.ovation.co.uk/miniature-H264-AVC-digital-video-recorder.html

I want to be able to backup without removing the SD card because I'm going to hide it inside my car but an ethernet port will be easily accessible.

I can use the web-gui but I've also written a C# program which uses a http get request and the System.IO.Stream class to save the files and that runs at about 3-3.5MBps.

The files are 5 minutes long each so they are all consistent sizes.

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  • What quality are you recording at? I mean, if you are trying to view a video, while it still records, you would have double the output on the interface on the DVR.
    – user725131
    Jul 26, 2017 at 7:50
  • @Cown It's recording in 1080p/30fps. When I'm downloading it is sitting doing nothing. It's not streaming at the same time. Thanks.
    – DonnellyOverflow
    Jul 26, 2017 at 7:54
  • Why not just use the SD card? Examples why it might be slow include: The reader is not rated for 45 MB/s but actually way lower. You wouldn't get 12.5 MB/s as you need to account for protocol overhead. It might be bad implementation of a HTTP server on the DVR. You might be downloading several small files. The DVR might be using the SD card for more than just video storage and utilize it while reading from it.
    – Seth
    Jul 26, 2017 at 7:55
  • You should add brand of DVR and brand of SD card in your question. :-)
    – user725131
    Jul 26, 2017 at 7:56
  • 1
    Embedded web servers are usually terrible. In all aspects, really.
    – Daniel B
    Jul 26, 2017 at 7:59

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