Can't reduce captured video movie size

pjl

pjl

n3wb
Nov 18, 2019
8
0
California, USA
I have Hikvision DS-2CD2H45FWD-IZS cameras and am using SecuritySpy on a Mac Mini. I had set SecuritySpy to continuously capture video and create a new movie file every hour on the hour. It was generating 1.36GB/hour. This was at 20fps. I reduced the frame rate to 15fps and expected to see an approximate 25% drop in the file size -- but I didn't: same 1.36GB/hour.

The cameras' video settings are:
  • Stream type: Main Stream (Normal)
  • Video Type: Video Stream
  • Resolution: 2688 x 1520
  • Bitrate Type: Variable
  • Video Quality: Medium
  • Frame Rate: 15fps
  • Max Bitrate: 3072 Kbps
  • Video Encoding: H.265
  • H.265+: Off
  • Profile: Main Profile
  • I Frame Interval: 40
  • SVC: OFF
  • Smoothing: 50
SecuritySpy is not recompressing the video. In the camera window of SecuritySpy, the cameras' Data Rate varies between 332-384KB/s. This did not noticeable change when I reduced the rate to 15fps.

So why doesn't reducing the fps reduce the data rate?
 
Depending on the motion the frame rate has very little to do with the amount of data If there is no motion the frames are just about empty except of for the Iframe which is full. reducing the frame rate will reduce the file size if there is a significant amount of motion. (cars driving down a busy street) . For that size resolution in H.265 the file is about what I would expect.

Read up on how h.264 and H.265 compression works.
 
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