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How to bandwidth is used by zebrix?
Definition of bandwidth
- The term « bandwidth » represents the amount of data a network connection can transfer each second.
- The bandwidth is generally expressed in “kilobits per second” of “megabits per second” (Kbit/sec or Mbits/sec).
- Thanks to this value, it is possible to estimate the transfer duration for a given file on a network.
- The size of a file commonly expressed in kilobytes, megabytes and gigabytes (please note that 1 bytes = 8 bits)
Common file size in digital signage projects
Size of image and video files that you will broadcast on your screens will vary depending on the quality of the image, the resolution (dimensions), and the duration (for videos).
Here are examples of files size:
| IMAGE | A full screen JPG image is generally between 200 and 500 KB (0.2 and 0.5 MB) |
|---|---|
| VIDEO | A good quality HD video rarely exceeds 1 MB per seconds of video (e.g. 30 seconds = 30 MB) |
| PAGE | A page size is the sum of all images and videos that are present in the page (e.g. 5 images and 1 video of 10 seconds will result in a total size of 12 MB ((5×500 KB) + 10 MB = 12 MB) |
| PLAYLIST | The playlist size is the sum of all items contained in the playlist (pages + videos + images). REMARK: if a content is present more than one time in the playlist, it only counts one time. |
How to know the size of a file?
In zebrix, you can see the size of files in the preview window that can be opened from the media, page and playlist section in zebrix by using the following icon:
Example
- A 10 Megabits/seconds internet connection can transfer 1,25 Megabytes each second (this value is obtained by dividing 10 per 8 to convert “bytes” into “bits”)
- On this internet connection, a 100 MB (Megabytes) file will require 80 seconds to transfer.
Zebrix features to optimize files size and bandwidth usage
Automatic transcoding
If the image file dimensions are bigger than the resolution of the display (which is very often the case with high definition images), zebrix will automatically reduce the image resolution to the highest resolution a screen is capable to display.
If the video file quality is too high, and the video format is not optimized, zebrix will automatically optimize the file size by compressing it (without visible image quality loss). Thanks to this process, a video file size could possibly be divided by 2 to 10 depending of specifications of the original file.
Only one transfer is required
An image or video file is only transferred the first time it is set on a screen. The file will then be permanently stored on the device. The next time the media is set on the screen, the playback will start almost instantly.
Playlist changes: only new files are transferred
When a playlist is updated, only new files need to be transferred. So, a small update in a huge playlist should be easy and quick to transfer to screens. Some operations don’t require much bandwidth Only adding new videos or lots of new HD images to screens would really require lots of bandwidth, all other operations don’t require lots of bandwidth:
- Removing a content from the playlist
- Changing a text in a page
- Changing a schedule
- …
Conclusion
When a content is set to a screen or a group of screens from zebrix, the transfer of every required files starts instantly to targeted screens, however, the content will only be displayed on screens when the content is completely transferred.
Please note that the bandwidth is shared between all devices present in the shops (laptops, servers, etc.) so the actual available bandwidth could be lower than the theoretical one. When two screens are present in the same shop, the bandwidth will be divided by two so it will take double of time to get the playlist transferred.
