Frequently Asked Question
How long can my DVR record ?
Last Updated 4 years ago
Almost all DVR are using H.264 compression or a variation of H.264 compression to store the video recording.
With the same resolution and quality settings, the resultant filesize of the video may differ by a lot.
Using the following 2 pictures for comparison.
Both are 1280 x 960 in resolution.
Both compression are set to HIGH.
However, the Flower Picture
is 1.28MB in size.
The Plain Picture
is only 88KB (0.088MB) in size.
Even with the same settings, different composition (content) of the picture can cause these 2 pictures to be 14.5 times different in the size.
That's the reason why Digital Camera can only estimate the numbers of photos you can take with a certain size memory card instead of telling you the exact numbers of photo you can take.
Now, H.264 Compression employs similar technique to compress the video file.
This means that even though the recording settings can be the same, the resultant video size can be differ greatly depending on the composition of the video and also the amount of movement in video.
That's the reason why it's not possible to determine the exact recording, but rather only give an estimation of the recording period.
If you want to know how long your recorder can record for initially, let it run for 1 week (to take into account the differences in activities over weekdays and weekend), then see how much space it consumed for that week. You can then extrapolate the total recording time based on the total storage of the DVR. That'll be the estimated recording time if the activities pattern and the cameras coverage doesn't change.
Other informations
Older DVR uses less efficient compression technique such as Wavelets, MPEG2, MJPEG compression. These compression technique are less efficient than H.264 compression and the variation of the compression for same settings doesn't differ by as much, so it's much easier to calculate storage period then. Do note that as the compression technique are less efficient, the same storage size would be able to save much shorter storage period compared to the current DVR which employed H.264 compression.
Some current DVR allows for FIX BITRATE compression settings for H.264. This means that the DVR will record 1 sec of video constantly at a fix filesize. You'll be able to calculate exactly how long the Storage can record for. However, what FIX BITRATE compression setting will do is for low bitrate settings, it'll greatly decrease the quality of video when the video require high bitrate, and it'll occupied unnecessary extra space when the video only require low bitrate.
With the same resolution and quality settings, the resultant filesize of the video may differ by a lot.
Using the following 2 pictures for comparison.
Both are 1280 x 960 in resolution.
Both compression are set to HIGH.
However, the Flower Picture
is 1.28MB in size.
The Plain Picture
is only 88KB (0.088MB) in size.
Even with the same settings, different composition (content) of the picture can cause these 2 pictures to be 14.5 times different in the size.
That's the reason why Digital Camera can only estimate the numbers of photos you can take with a certain size memory card instead of telling you the exact numbers of photo you can take.
Now, H.264 Compression employs similar technique to compress the video file.
This means that even though the recording settings can be the same, the resultant video size can be differ greatly depending on the composition of the video and also the amount of movement in video.
That's the reason why it's not possible to determine the exact recording, but rather only give an estimation of the recording period.
If you want to know how long your recorder can record for initially, let it run for 1 week (to take into account the differences in activities over weekdays and weekend), then see how much space it consumed for that week. You can then extrapolate the total recording time based on the total storage of the DVR. That'll be the estimated recording time if the activities pattern and the cameras coverage doesn't change.
Other informations
Older DVR uses less efficient compression technique such as Wavelets, MPEG2, MJPEG compression. These compression technique are less efficient than H.264 compression and the variation of the compression for same settings doesn't differ by as much, so it's much easier to calculate storage period then. Do note that as the compression technique are less efficient, the same storage size would be able to save much shorter storage period compared to the current DVR which employed H.264 compression.
Some current DVR allows for FIX BITRATE compression settings for H.264. This means that the DVR will record 1 sec of video constantly at a fix filesize. You'll be able to calculate exactly how long the Storage can record for. However, what FIX BITRATE compression setting will do is for low bitrate settings, it'll greatly decrease the quality of video when the video require high bitrate, and it'll occupied unnecessary extra space when the video only require low bitrate.