Screen broadcast, QR code live streaming and monitoring: detailed function descriptions

Three things are explained separately: casting the screen, watching the screen, and how data is transferred underneath. 79 features in all, each in one sentence saying what it does and who it applies to.

5Feature Grouping

79feature by feature

2Client (Teacher Client / Student Client)

1Universal installation package

Screen Broadcast and Teaching Demonstration 27 items

A suite of functions for projecting the screen to students. Screen broadcast, demonstration, live streaming, and cinema mode – only one runs at a time; starting a new one automatically stops the previous one, so they never conflict.

Screen Broadcast: Broadcast the teacher's entire desktop to the whole class in real time, student PCs automatically pop up a full-screen view
Window broadcast (bound window): Broadcast only the specified window; students cannot see other content on the desktop. Suitable for demonstrating only a certain software.
Area broadcast (select screen area): Use the mouse to select an area on the screen to broadcast only that area; you can cancel it anytime to restore full-screen broadcast.
Broadcast by list: Click or drag-select the computers and groups to receive; with none selected it goes straight to the whole class, and student PCs that connect later join automatically
Annotate during broadcasting: When broadcasting, an annotation toolbar appears, allowing selection of pen color/thickness, eraser, shapes, arrows, text, and highlighter; directly circle and annotate on the screen for explanation.
Annotation toolbar scales with screen ratio: Toolbar scales proportionally on 4K high-resolution screens, will not be too small to read.
Full-screen broadcast locks student keyboard and mouse: There are toggles (default on) in both the broadcast popup and broadcast settings; when receiving in full screen, student keyboard and mouse are locked, they can only watch but not interact
Student client receives in fullscreen or windowed mode: Students can receive in full-screen or switch to a window, watching the teacher's demonstration while following along.
Student demonstration: The demonstrating student's screen is pushed as the broadcast to the whole class or selected classmates; the student keeps working, and the teacher can watch or take over anytime
Live Streaming: Live broadcast of screen + camera + audio, camera overlay as picture-in-picture at bottom right, viewers can switch sources.
Broadcast with audio and camera together: Screen broadcast can include system audio, the teacher's microphone, and the camera at the same time, with no loss of clarity
Network Cinema: Synchronously play a video file (mp4 / mkv / avi / mov / wmv) to the entire class, while the teacher opens a separate window to monitor progress.
Shared whiteboard: Open a real-time shared drawing board; the teacher writes and draws, and the student side sees it synchronously, equivalent to an electronic blackboard.
Student collaborative whiteboard drawing: One-click on the whiteboard toolbar allows students to draw on the whiteboard as well; each student's strokes are displayed in real-time with a distinct color to the whole class, and permission can be revoked at any time.
File Download Panel During Broadcast: On the broadcast screen, provide students with a file list. Materials distributed by the teacher during class can be downloaded by students with a click.
Submit Homework Panel During Broadcast: Students can directly fill in their student ID, name, and class in the broadcast screen, and drag and drop files to submit homework, without exiting the broadcast.
Selectable transport: Three modes: broadcast, multicast, unicast. Choose one based on the computer lab switch and network policy.
Desktop Recording: One-click start or stop recording teacher's screen to file; can be played back after class or distributed as material to the whole class.
Student note screenshot: Students press F2 to take a screenshot for notes while watching a broadcast, automatically saved to "Documents / Class Notes".
Adjustable broadcast parameters: Resolution, frame rate, and bitrate are adjusted according to the computer lab network conditions, balancing clarity and smoothness
Auto-exclude demo machines: When broadcasting, the machine currently doing student demonstration is automatically excluded to avoid looping the screen back.
Broadcast drop-down menu: Full screen, window, region, bound window, and broadcast settings in one drop-down menu, with settings remembered
Send the board: Save the current annotation page (background plus annotations) as an image and send it to student PCs without interrupting the broadcast
Annotation toolbar stays off the broadcast: The teacher sees the toolbar, but it never appears in the broadcast or screenshots; similar tools are grouped, and it can be pinned to the top
Two ratios for windowed viewing: In windowed viewing, students can scale to the window or keep the original ratio, switch it themselves, and zoom with Ctrl+scroll wheel
Students can record the broadcast: Students can record the broadcast video and audio they receive and review it after class
Lossless quality mode: Broadcast can switch to lossless quality; when the screen stops moving it sharpens automatically, ideal for small text and drawings

Scan to live stream · watch without client 9 items

The teacher console has a built-in live streaming service that generates a QR code with one click. Mobile phones, tablets, and laptops without the student client can scan the QR code on the same classroom network to watch in a browser—view-only, no control rights.

One-click broadcast generates QR code: Click "Live" to generate a QR code and intranet address for viewing; mobile phones and tablets can scan the code to open directly in a browser.
No installation, no plugin required: No app or browser plugin required on the viewing end; WeChat's built-in browser can play directly.
Screen with computer audio: Live broadcast synchronously carries the teacher's PC audio; when no sound card is detected, the status bar clearly prompts 'No audio output device'.
Camera picture-in-picture: The camera image is overlaid in the bottom-right corner. The viewer can switch between the computer screen and the camera feed.
Download materials from view page: The file panel at the top right of the viewing page lists materials distributed by the teacher during class, which can be downloaded directly on mobile phones.
Submit homework online from the viewing page: The viewer fills in student ID, name, and class, then submits the homework file. Files are archived in individual directories per student and appear in the teacher's assignment collection panel.
Classroom LAN only: Accessible only within the same classroom network. The viewing end is purely for viewing, with no control permissions.
Live streaming status indicator: The 'Live' indicator on the teacher console's main interface stays on, and displays the real-time count of devices watching
Hide window and continue live streaming: Collapsing the QR code window does not affect the live stream; click 'Live' again to recall it at any time.

Voice teaching and live classroom captions 10 items

Everything to do with sound in class sits behind one “Voice Teaching” entry: first select student PCs or a group below, then open it and pick a mode — voice broadcast, teacher–student intercom, group intercom, raise-hand-to-speak, designated speaker, or voice group chat. Only one runs at a time; switching modes automatically stops the previous one, so audio never overlaps. The pop-up status panel shows who is speaking, volume levels, mute and stop at a glance. During a screen broadcast you can also open the mic to narrate and turn speech into live captions — voice teaching and screen broadcasting never interrupt each other. Everything runs over the LAN and the sound never leaves the classroom, with identical results across Windows and Linux.

Related pages:Interactive TeachingSolutions

Voice broadcast: Open “Voice Teaching → Voice broadcast”; the teacher speaks into the mic and the sound is pushed in real time to the selected student PCs or the whole class. At any time you can use “Designated speaker” to let a student take the floor. When you stop, the student floating panel closes and the mic turns off automatically, so a student mic is never left open.
Teacher–student intercom: Hold a one-to-one live conversation with a single student, started by right-clicking that student; the exchange can be “demonstrated to the whole class” so other students can watch the Q&A, and the teacher can end it at any time.
Group intercom: Split students into groups so members of the same group can talk to each other; the teacher can “listen in” on any group, switch between groups, follow each discussion without interrupting it, and step in to guide when needed.
Raise-to-speak and assigned speaker: During Q&A, students raise a hand to “grab the mic”; whoever grabs it first gets to speak. The teacher sees the speaker and the waiting queue at a glance and can “take it back and start another round,” or use “Designated speaker” to pick a specific student directly.
Voice group chat: Students press and hold to record a short message to the group; the whole class can play each one back, with speaker and time shown. The teacher can “export all” at once or clear and start over — ideal for keeping a record of speaking practice, reading aloud and Q&A.
Live classroom captions: The teacher’s speech is turned into text in real time by on-device offline speech recognition and shown as captions at the bottom of every student screen; Chinese and English can be mixed. Recognition runs locally on the teacher’s machine and nothing is uploaded to the cloud (available when the teacher app runs on Windows).
Adjustable caption position: The teacher drags the caption bar to position it, and the captions on every student screen follow to the same spot, so they never cover what is being explained.
Save transcripts: The whole lesson’s speech is kept, sentence by sentence, as a transcript in the teacher panel; at any time you can “Save text” to export it to a file and hand it to students after class as board notes or dictation material.
Broadcast with microphone and captions: During a screen broadcast, one tick in the broadcast settings turns on the teacher’s mic and automatically opens live captions — students watch the teacher’s screen, hear the narration and see the captions all at once. Voice teaching and screen broadcasting run at the same time without interrupting each other.
Microphone echo cancellation: When the teacher’s machine plays sound out loud (for example a video), echo picked up again by the mic is cancelled automatically, so students hear cleaner speech without howling or feedback.

Monitor and operate on individual student 21 items

In the middle student area, each machine has a card for a quick overview of the entire class. Single-click to select, right-click to bring up the context menu, double-click to directly remote control.

Real-time thumbnail monitoring: Each student card displays a real-time thumbnail of the student's screen and marks the status: online, hand raised, or presenting.
Adjustable card size: The "Zoom In/Out" at the bottom adjusts card size between 80%–160%. The computer lab projector and 4K all-in-one are adjusted separately, and settings are remembered.
Two arrangement methods: Default sorted by seat (IP), can switch to alphabetical order A→Z or reverse Z→A with one click.
Search from the top bar: The top search bar can search for functions and computer names, quickly locating when there are many machines.
Group Teaching: Divide students into different groups; many operations can be applied only to a specific group.
Remote Control: Double-click a student card to open a remote control window, take over the student's mouse and keyboard, and perform operations or demonstrations on their behalf.
Instant discussion: One-on-one chat with a specific student
Capture current screen: Save the student's current screen as an image in 'Documents / Classroom Snapshots' for evidence or as an example.
Set as / Cancel Group Leader: One group leader per group; setting a new one replaces the old, shown right on the card
Classroom evaluation: add/subtract points: 6 positive items (e.g., active participation +1, max +3), 4 negative items (e.g., distracted −1). Customizable with +N / −N.
Start / Cancel Demonstration: Show the student's screen to the whole class, or stop the demonstration
Cancel hand-raising: Clear the student's hand-raising status
Clear offline computers: One-click clear offline cards, after replacing machines in the computer lab, the list will not retain old records
Select target before operation: All actions targeting computers require selecting a machine or group first. If none selected, a confirmation dialog pops up to prevent accidentally affecting the entire class.
Bottom status bar: Current teaching channel and online/total stations at a glance
End with one click from status icons: Cards show small icons by status (broadcast, voice, blackout, internet blocked, group control, exam, hand raised, and more); click one to end it
In-progress activity bar: Features in progress are listed above the list; end each one individually or all at once
Drag to change groups: Drag a student card to another group to move it; selected PCs can be dragged together
Easier selection: Selected machines are clearly highlighted, with Ctrl multi-select, Shift range select, and drag select; right-click runs toolbar features directly on all selected PCs
Monitoring Management: Monitor student screens in multiple splits at once
Hardware monitoring: Inventory student PC hardware and view resource usage

Transmission and image quality engineering 12 items

Dozens of machines in a lab receiving screens simultaneously—whether it lags depends entirely on the transmission layer. Below are the specific measures already implemented in the product, not just adjectives.

Related pages:Block-Level Streaming Boot

Adaptive frame rate and quality (QoS): Automatically adjust between frame rate and clarity based on real-time packet loss and backlog; when network is poor, prioritize smoothness.
Motion-adaptive video quality grading: For fast-changing areas, reduce quality to ensure smoothness; for static areas, maintain clarity so text is readable and video is not blurry.
CRC32 hardware hash differencing: Calculate hash block by block using hardware instructions, only send the actually changed blocks; static images consume almost no bandwidth.
Screen capture and encoding dual-stage pipeline: Capturing the next frame overlaps with encoding the current frame, resulting in more stable frame output on the teacher end.
libjpeg-turbo direct encoding/decoding: Teacher-side encoding and student-side decoding both bypass the common image library pipeline, allowing the same machine to deliver a few more frames.
Parallel decoding of multiple tiles: The client uses a thread pool to decode multiple screens simultaneously, so even older student PCs with low specifications can keep up.
X11 SHM double-buffered zero-copy: On Linux, screen capture uses shared-memory double buffering instead of deep-copying the whole screen every frame, noticeably lowering load
Lightweight XOR FEC: Every 4 data fragments come with 1 parity fragment; if one packet is lost, it can be recovered without retransmission, reducing screen tearing.
AIMD adaptive transmission rate: Fast queuing on gigabit networks, automatic convergence on 100-megabit networks; won't flood and bring down the entire computer lab
UDP send independent thread: Packet sending does not block the UI thread; during broadcast, the teacher's interface remains responsive.
Keyframe TCP fallback: The first frame and key frames of the broadcast use a reliable channel, so students will not experience a black screen or long wait for the initial image.
Keep-alive during idle period: No large black blocks, corruption, or ghosting even when the screen doesn't change for a long time

See other functions such as classroom interaction, exam and homework, classroom control, etc. cc-class Complete feature list； See step-by-step operation steps and illustrations cc-class user manual.

Linux screen broadcasting softwarecc-class low-latency broadcasting and monitoring

A common problem under Wayland

How cc-class solves it

Broadcast · Monitor · Take over, all in one

Screen Broadcast

Student Demonstration

Live Streaming

Network Cinema

Screen Watching

Remote Takeover

Shared whiteboard

One-click blackout

Screen Broadcast and Teaching Demonstration 27 items

Scan to live stream · watch without client 9 items

Voice teaching and live classroom captions 10 items

Monitor and operate on individual student 21 items

Transmission and image quality engineering 12 items

UDP auto-discovery

Low-latency encoding

Xorg + XTest

Adjustable resolution / frame rate

Auto Reconnect

Cross-platform consistency

Demonstrate while explaining

Synchronized micro-lecture playback

Monitor all screens

Hands-on demonstration training

Linux Classroom Management Software

Linux teaching software

cc-class Digital Classroom Software

Comprehensive Solution

Run a screen broadcasting software that truly broadcasts in your Linux computer lab

Linux screen broadcasting software
cc-class low-latency broadcasting and monitoring