“You cannot change the laws of physics, Captain.” – Montgomery Scott
Remember that a USB 2.0 connected webcam is bandwidth limited to delivering a maximum of 480 mbps (60 Mbytes/sec) to the host computer. Because of this fact, and given that the video frames from the webcam are uncompressed, the USB 2.0 link can only deliver 720p30.
Microsoft is a little confusing about the capabilities of the LifeCam Studio. For example, their stated specifications for the device are pictured below.
They clearly claim to have a 1080p sensor, but only purports to deliver a 720p stream in support of video chat.
Yet some people, including the team behind Category 5 Technology TV, have claimed that they were able to get real 1080p30 video from the LifeCam Studio. This claim I initially found questionable, since it wasn’t backed up by satisfactory technical specifics. Robbie Ferguson from Cat5 TV once stated, “…the user MUST use "professional" software!” without stating what that might be. That said, I have recently been able to both verify and explain that claim.
The LifeCam Studio is UVC 1.1 compliant. The UVC 1.1 standard, which hails from 2005, includes a way to instruct a webcam to send MJPEG encoded frames over the USB bus. MJPEG compression is capable of compression rates as high as 20:1.
In the case of uncompressed video, 1920 x 1080 x 30 f/s @ 24 bits/pixel requires 186 Mbytes/sec. That’s dramatically more than the 60 Mbytes/sec (480 megabits/sec) limit of USB 2.0. If MJPEG compression can achieve even just 10:1 compression, that video stream is reduced to a more manageable 18.6 Mbytes/sec (148.8 megabits/sec) well within the grasp of the USB 2.0 link.
If an application takes advantage of the MJPEG capability of the LifeCam Studio, it can reliably extract a 1080p30 stream from the camera.
That’s a BIG if! The trouble is that few consumer applications are that sophisticated about setting up a webcam, but things are improving as time goes on.
vMix and Wirecast can both get 1080p30 from the LifeCam Studio, but costing several hundred dollars each, those applications are hardly what most people consider accessible. On the other hand, the LifeCam Studio does seem to deliver 1080p30 when used with SparkoCam.
Incidentally, there is a problem using the combination of Windows 7 Pro 64 bit, Wirecast 6.x 64 bit and the LifeCam Studio. That particular combination just doesn’t work well together. The camera doesn’t get initialized correctly.
Of course, Skype is something of a special case. Skype has a long history of partnering with hardware makers to optimize the user experience. Since they are under the Microsoft banner it’s safe to assume that they make the most of the LifeCam Studio. Although, I can’t recall Skype making any claims to go beyond 720p video.
This little mystery has been on my plate a long while. Just over a year ago I bought a Microsoft LifeCam Studio specifically to look into the matter. It wasn’t until my recent trial of vMix that the answer became clear.
While the question has been answered, the LifeCam Studio has proven to be less than impressive in use. It’s major advantage is that, at around $60, it’s cheaper that it’s major rivals. It’s output simply can’t compare to the Logitech C920 or C930e, which remain my benchmarks for non-PTZ webcams.