YUV444 support
By default, macOS VDA encodes the remote desktop screen using YUV420 color format, which compresses color information (halved in both horizontal and vertical directions). This works well for most use cases, however, may cause subtle color blurring - especially on sharp color edges, small colored text, and UI elements with fine color details.
YUV444 preserves full color resolution — every pixel retains its exact original color. This delivers a visually lossless remote desktop experience, virtually indistinguishable from a local display.
Use case examples that need YUV444 feature enabled
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Graphic designers and digital artists (color-accurate rendering)
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Medical imaging professionals (no color artifacts on diagnostic images)
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CAD/CAM engineers (precise color lines and fine detail)
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Developer & tester who enjoys sharp & clear colored syntax highlighting etc.
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Any user who sensitive to color blurriness on text and UI edges
How to Enable YUV444
YUV444 requires two policies to be configured:
Step 1: Set the Video Codec Usage Policy
Configure the Citrix policy “Use video codec for compression” to: For the entire screen (UseVideoCodecIfAvailable).
This enables full-screen H.264/H.265 hardware encoding, which is a prerequisite for YUV444 as performance considerations
Step 2: Set the Visual Quality Policy
Configure the Citrix policy “Visual quality” to: Always lossless or Build to lossless
Visual quality settings of Low, Medium, or High will NOT activate YUV444 - the session will remain in YUV420 mode.
Requirements
VDA (Server-Side)
| Requirement | Details |
|---|---|
| Hardware | Physical Mac hardware (Mac mini, Mac Studio, Mac Pro, MacBook). YUV444 is not supported on virtual machines — the VDA automatically falls back to YUV420 on VMs. |
| macOS | macOS with VideoToolbox hardware encoding support (macOS 14+) |
| Codec | H.264 (High 4:4:4 Predictive profile) or H.265/HEVC (Main 4:4:4 profile) |
Client (Citrix Workspace App)
| Requirement | Details |
|---|---|
| CWA version | Must support H.264 YUV444 color format capability. Recent versions of CWA for Windows, Mac. Linux doesn’t support this. |
| Hardware decoding | Client must be able to decode H.264 High 4:4:4 Predictive profile (or HEVC Main 4:4:4 for H.265). Most modern GPUs support this. |
Network
| Requirement | Details |
|---|---|
| Bandwidth | YUV444 produces approximately 1.5–2 times more data than YUV420 for the same frame. |
| Recommendation | A stable connection with sufficient bandwidth headroom - 50 Mbps or higher. LAN or high-quality WAN connections are recommended. |
Note:
- If CWA client lacks hardware decoder for YUV444, enable this feature could cause client performance degraded substantially – Enable this feature with caution.
YUV444 feature will be automatically disabled when screen sharing policy is enabled.
Troubleshooting
How to Verify YUV444 is Active
Method 1: Check VDA Session Registry
After connecting a session, run command on VDA side terminal:
sudo hdxmonitor graphics dump
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YUVFormat: YUV444 → YUV444 is active
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YUVFormat: YUV420 → YUV420 (fallback)
Method 2: Citrix Director / Monitor
Session details in Citrix Director may show the active video codec and color format.
Symptoms and solutions
| Issue | Cause | Solution |
|---|---|---|
| YUV444 not activating despite correct policy | Running on a virtual machine | Use physical Mac hardware |
| YUV444 not activating
|
Visual quality set to Low / Medium / High | Change to “Build to lossless” or “Always lossless” |
| Video codec policy not set to “Use when available” | Set policy to UseVideoCodecIfAvailable | |
| Client doesn’t support YUV444 | Update Citrix Workspace App to latest version | |
| Screen sharing enabled | Disable screen sharing policy | |
| Poor frame rate with YUV444 | Insufficient bandwidth or client no hardware support | Improve network bandwidth or use client has hardware codec support |