Vista voice recognition not yet up to scratch

A video showing a failed public demonstration of Windows Vista's voice recognition technology has emerged on the internet.

The demo, during Microsoft's Financial Analysts Meeting in Seattle, shows the operator instructing the machine to type 'Dear Mum', to which it responds with 'Dear Aunt'.

Further attempts to correct the error using voice commands result in more mistakes, to the amusement of the audience.

The video of the Vista speech recognition demo was posted on the video sharing site, YouTube.

Gadget blog Gizmodo has located a blog post on MSDN by Larry Osterman, a software design engineer at Microsoft, admitting responsibility for the bug.

Osterman explained that the problem was due to a feedback loop.

"There's a timing issue that is causing a positive feedback loop that resulted from a signal being fed back into an amplifier," Osterman wrote.

The code is designed to handle feedback, but two low-level bugs combined to cause the problem.

"As a consequence of these two very subtle low level bugs, the speech recognition engine wasn't able to correctly control the gain on the microphone. When it did, it hit the notification feedback loop, which caused the microphone to clip, which meant that the samples being received by the speech recognition engine weren't accurate," explained Osterman.

• Windows Vista speech recognition demo video