YUY2 is a common way to transport video where luminance (Y) information is stored for each pixel and chroma information is shared between neighboring pixels using 4:2:2 sampling. In practical camera-module work, the important point is that YUY2 is not heavily compressed like MJPEG. The host receives a large amount of image data for every frame.
Uncompressed output avoids JPEG compression artifacts and removes the need to decode each frame. This can be useful for computer vision, image analysis or applications where consistent pixel data is more important than saving bandwidth. The host can process frames directly after capture, although color conversion may still be needed.
Because YUY2 sends much more data than compressed MJPEG, interface bandwidth becomes a limit quickly. A USB2.0 module might offer 1080p at a modest YUY2 frame rate while providing a much higher frame rate in MJPEG. The same principle applies at 4K: uncompressed video can exceed the practical throughput of the interface.
This is why a specification table often shows different maximum frame rates for YUY2 and MJPEG.
Human vision is generally more sensitive to brightness detail than to color detail. 4:2:2 sampling keeps luminance information at full horizontal pixel frequency while sharing chroma samples across pairs of pixels. The result reduces color-data volume compared with full RGB while remaining much less compressed than JPEG.
Compression artifacts are one variable, but lens quality, exposure, noise, ISP processing and sensor output can dominate image quality. A noisy, poorly focused YUY2 frame can be less useful than a well-exposed MJPEG frame. The correct format depends on the downstream task.
It is useful when the host needs predictable frame data, the resolution/frame-rate combination fits within bandwidth, and CPU/GPU resources can process the stream. It is common in machine vision prototypes, measurement, algorithm development and systems that want to avoid JPEG decoding.
Look for the exact resolution and frame rate listed under YUY2, not only the module’s maximum sensor resolution. Also check USB version, whether the host supports the requested mode and whether multiple cameras share the bus.
At the same resolution and frame rate, YUY2 typically requires far more transport data than MJPEG because each frame is sent with little or no image compression. This is why a USB camera can offer a high MJPEG frame rate while its YUY2 mode is much slower. The sensor has not changed; the transport burden has.
If the algorithm already expects uncompressed YUV frames, YUY2 can remove a decode step and make pixel access predictable. That can be useful for measurement or prototyping. The trade-off is bus load, so designers should check whether the host has enough bandwidth for the desired resolution and number of cameras.
It is generally transported without JPEG-style compression, but it uses 4:2:2 chroma subsampling, so it is not the same as full RGB sampling.
The uncompressed stream requires much more USB bandwidth per frame.
No. Some applications can use MJPEG or other formats effectively. Choose based on bandwidth, latency, processing and image requirements.
