The issue was first noticed almost immediately after Windows 10’s Anniversary Update was released earlier this month. However, it has only just begun to receive mass attention, as irate developers complained in a support thread that customers could no longer use their cameras in their apps.
The Anniversary Update includes a significant rethinking of how Windows handles webcams and exposes them to apps. Apps can no longer connect directly to webcams. Instead, they connect to a “frame server” that’s effectively a virtual replication of the actual webcam. They retrieve the image data from this frame server.
Microsoft says the new approach offers significantly greater performance. It also allows multiple applications to use the webcam at the same time. Previously, if you were making a video call with Skype, you could not take a photo with your webcam or use it to sign-in to your PC with Windows Hello. With the Anniversary Update installed, this changes. Because apps connect to a camera server rather than the actual hardware, multiple apps can receive data from the camera at the same time.
This change induced an overhaul of how webcam data is encoded. USB webcams usually support a variety of formats. Consumer models tend to use compressed video streams, such as MJPEG and H.264, to save on data. Microsoft’s new frame server only supports uncompressed streams, however.
Uncompressing data is quite CPU-intensive. Because Microsoft now allows several apps to use the camera at once, it considered that having multiple apps simultaneously uncompressing data could be quite taxing on the processor, decreasing system performance. Therefore, it offers uncompressed data or nothing, based on the rationale that apps that expect compressed data will immediately uncompress it anyway.
Unfortunately, Microsoft didn’t think the new approach through. Many webcams encode their data in compressed streams. If they try to do so with the Anniversary Update installed, it will fail. Likewise, if an app tries to directly connect to the camera, or retrieve compressed data from it, it will fail and crash. Microsoft expected the change to go unnoticed by users, a behind-the-scenes tweak to increase performance. Instead, millions of webcams are unusable in most applications.
In the support thread, angry users and developers blasted Microsoft for making the change without even advertising it. The company had not previously advised that apps and cameras should be updated to support the new frame server and encoding types. Users can no longer access their cameras in apps and are asking developers why not. The developers are passing the same question along to Microsoft.
After initially defending the new camera behaviour, Microsoft backtracked last week and admitted it made a major mistake. It confessed that some of the points made “cannot be argued with” and said it is working out a way to provide apps with access to compressed streams. It intends to release a Windows 10 update that will fix some of the issues, although it won’t arrive for at least a month.
Microsoft has been criticised for not noticing the major problem during the development of the Anniversary Update. Microsoft’s own apps, including Skype, are affected by the changes, leaving people unable to make video calls with the most popular webcams. Extremely successful models, including Logitech’s C920, widely regarded as the best all-rounder webcam, are affected.
The issue is the second major problem to crop up since the launch of the Windows 10 Anniversary Update. Many users are also complaining of serious freezing issues, a bug that Microsoft has confirmed it is investigating. Users who have found their webcam is unusable after the Anniversary Update will need to either wait until September or consider rolling back to their previous version of Windows, possible for 10 days after upgrading.
