How Remoqa sends your screen
Typing, scrolling and opening windows change different amounts of the screen. Here is how Remoqa adjusts what it sends and how often it captures.
The short version
Remoqa’s screen protocol sends changed regions when a partial update is useful, reduces the frame rate when sending falls behind and captures less often during quiet periods.
When you type into a document, a few letters appear while the toolbar and surrounding windows stay still. Scrolling a page changes a much larger area. Remoqa uses these differences to decide how much screen data to send. Here is how its desktop capture and delivery work together during a session.
Find the parts that changed
The remote computer compares each captured screen with the previous one in small blocks. It groups neighbouring changed blocks into rectangles, encodes those regions with VP9 and sends them with their positions. The viewer applies these updates to the picture it already has. These changed areas are often called dirty regions.
Opening a small menu may produce just a few rectangles. Maximising a window or playing a video can change most of the screen, so a full refresh becomes more useful. Remoqa also sends a full update at the start of a session, periodically and when a refresh is requested. This gives the viewer a complete picture to build on.
Adjust the frame rate to the connection
FPS means frames per second. A higher capture rate can make scrolling and movement look smoother, provided the connection and both devices can keep up.
When sending falls behind and an unsent update is displaced in the queue, Remoqa lowers its capture target. The current desktop sender uses steps of 30, 20, 15, 10 and 5 FPS. A run of successful sends gradually raises the target again.
This adjustment changes how often images are captured while keeping the encoding quality setting. On a busy connection, motion can become less fluid while text retains its detail. The displayed frame rate also depends on screen activity, encoding time and the receiving device.
Do less work while the screen is still
An unchanged capture can be skipped. After a few seconds without visible changes, the desktop capture loop checks the screen less often. Remote mouse or keyboard input, clipboard activity or a visible screen change brings it back to active capture.
A quiet session still sends small updates to show that it is alive and occasional full refreshes to keep the picture in sync. Reduced capture and fewer updates help limit processing and traffic while you read a document or leave a settings window open.
Deliver large updates in parallel
When parallel video delivery is available, Remoqa can divide a full refresh into independently encoded pieces and send them over several connections. The viewer collects the complete refresh before displaying it. Later partial updates follow in order, so they are applied to the right version of the screen.
Using several connections can help deliver a large update when bandwidth is available. The result still depends on the internet connection, the route and how quickly each device can process the image.
Try it with the work you normally do
Documents, code editors and settings tend to change in small areas between pauses. Full-screen video and rapid scrolling change more pixels and need more frequent, larger updates. Your traffic use depends on this activity, the screen resolution and the length of the session.
Try a short session over the network you plan to use and check how it feels.
- Type a few lines
Open a document or editor and check how quickly new characters appear and how easy the text is to read.
- Scroll and open a window
Move through a longer page, then maximise a window. Notice how the connection handles a larger change.
- Pause, then continue
Read for a moment, then type again. Check that the session responds when you return to work.