Overview

This article will provide recommendations regarding some of the settings used for files that are uploaded to workspaces and associated to documents, as well as some recommendations on compressing files.

Online or offline availability

Available online only (recommended)

We recommend that files are uploaded tp workspaces with the setting Available online only.

This means that the app user will have to be online to access the file for the first time. Once the file has been accessed, it will be cached on their device and it will become available offline.

This approach ensures a quick activation process and does not take up additional storage on user's devices.

Available offline (not recommended)

If app users will not have access to internet after they initially activate the workspace, we recommend that you select the Available offline setting for your documents.

With this setting, files will be downloaded to the device during workspace activation and will be available for viewing at any time.

Important: Using the Available offline setting can significantly increase the app activation time for the user. On average, only 3% of all interactions with SpotMe apps are carried out while the user is offline so using this setting is often quite unnecessary.

Compressing files

As a general rule, files uploaded to Backstage should not exceed 100 MB.

We recommend that you always compress the files that you upload, as smaller files will work more smoothly in the workspace.

There are a number of tools that can be used to reduce the size of your files to make them more manageable. The tool you use will depend on the type of file.

PDF files

smallpdf.com is an easy to use and reliable tool that reduces the size of your files while keeping quality loss at a minimum (if any).

Images

For mac users, ImageOptim is easy to use and compresses photos and graphics up to 60% without any quality loss. Windows users can also use IrfanView.

Audio and video files

Recommended codec/containers

Following the below recommendations will ensure that your video runs smoothly on the app:

• Container: MP4
• Video codec: H.264
• Audio codec: AAC
• Framerate: 25 or 29.99 FPS

Recommended resolutions

For web app users watching videos on full screen, the recommended resolution for videos would be 1280x720p.

If your participants will be watching video on both mobile and web app, recommended resolution for videos is 960x540p.

Compressing AV files:

HandBrake allows you to adjust the settings on the AV file to reduce its size while maintaining quality.

1. Install and open HandBrake.

2. Select your AV file using the Summary tab.

3. Enter the following recommended compression settings:

In Summary tab > Format: MP4 file

In Video tab, select:

• Video encoder: H.264 (AVC)
• Storage size: Do not change this. These values should default to your source file's original dimensions.
• Frame rate (FPS): 25 (PAL film/video)
• Peak frame rate
• Quality > Average bitrate > 600 kbps
• 2-pass encoding
• Average bitrate: 600kbps

In Audio tab, select

• Codec: AAC (CoreAudio)
• Mixdown: Stereo
• Samplerate: 48
• Bitrate: 128

Once you've adjusted these AV settings you can hit Start to begin compressing the video. This will take a while.

What if your video still exceeds 100MB?

For large video files, the above compression settings may not be enough to get the file below the 100MB limit.

If so, you will need to further reduce the bitrate per second.

To know how much you need to reduce it by, you first need to calculate the total bitrate per second that you are targeting for the video once it is compressed.

Calculations:

• Let's consider that you are aiming to have a video that will be 95MB (so less than 100 MB) after it is compressed.
• Also note that 1 MB (megabyte) = 8192 kilobits.
• You will need to calculate what the total video length is, in seconds, before compression.
  For this example, the video is 1704 seconds long (i.e. 28 min and 24 seconds).

→ To calculate the total bitrate per second in the compressed video:
(95 x 8192) / 1704 seconds = 456.713 kbs (rounded to 457 kbs)

→ To calculate the video bitrate per second in the compressed video, we need to remove the audio bitrate: 456 - 128 = 329 kbs

Therefore, the total video bitrate per second for this video, in order to compress it down to 95MB in size, is 329 kbs.

Compressing in Handbrake:

1. Open the file in Handbrake and change the file settings as described in the Audio and video files section above.
   
   
2. Go to the Video tab and enter the calculated video bitrate per second value (here it was 329 kbps):
   
   
3. Hit Start to begin compressing the video. This will take a while.
   
   The final compressed video will be 95 MB. You can now upload it to your workspace.