Microsoft says a fix is on the way for a video encoding issue in the Windows 10 Anniversary Update that has left people unable to access their USB webcams and applications.
Multiple peeps and developers have reported issues with their cameras or software not working following the installation of the Windows 10 Anniversary Update.
Microsoft, via Windows Camera team engineer Mike Morante, says that the problem is due to a change in the way Windows 10 now handles video streams from USB cameras. Specifically, Windows 10 stops software from accessing streams encoded in compressed MJPEG and H.264 formats, and instead forces them to use uncompressed YUV or NV12 streams.
If a program expects MJPEG or H.264 from a USB-connected cam, it won't be able to get it. Bye-bye video feed.
Morante said this change was made in the operating system to improve performance when a PC is running multiple applications that request access to the same webcam. Rather than have, say, three apps streaming H.264 from a cam over USB and all three decompressing the video at the same time, the apps should pull a single YUV or NV12 stream from the OS, which does the H.264 decompression for them. That means one decompression operation is happening during streaming, not three.
Unfortunately, apps don't expect this, and fall over.
While a number of developers were notified and able to update their products, others were not, and when the Windows 10 Anniversary Update was released, some USB cameras and image-processing applications that were set to look for the MJPEG and H.264 video feeds no longer worked.
"MJPEG and H.264 being decoded/filtered out is the result of a set of features we needed to implement, and this behavior was planned, designed, tested, and flighted out to our partners and Windows Insiders around the end of January of this year," Morante wrote.
"We worked with partners to make sure their applications continued to function throughout this change, but we have done a poor job communicating this change out to you guys."
Morante said that Microsoft is working on a fix for both encoding formats. A fix for MJPEG video feeds will be due out in September, with H.264 support to be added at a following, unspecified date.
El Reg contacted Microsoft for additional comment on the matter, but received the following advertising blurb:
Windows 10 continues to have the highest customer satisfaction of any version of Windows. We have seen a small number of reports of unexpected behaviors following the Windows 10 Anniversary Update. Engineering and customer support are investigating these on a case by case basis and offering trouble-shooting tips as necessary.
Make of that what you will.
In the meantime, users on Microsoft's support thread have offered a few possible tips and workarounds for the issue. ®