It first showed up in 25.0a1/20130711. The regression range is: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=04d8c309fe72&tochange=dde4dcd6fa46 It's likely a regression from bug 866675. Signature `anonymous namespace''::mono_to_stereo<float>(float*, long, float*) More Reports Search UUID 515aa9de-0f41-4a91-9a94-ca0b62130714 Date Processed 2013-07-14 02:06:21.329141 Uptime 491 Last Crash 595 seconds before submission Install Age 1276 since version was first installed. Install Time 2013-07-14 00:52:49 Product Firefox Version 25.0a1 Build ID 20130713030205 Release Channel nightly OS Windows NT OS Version 6.1.7601 Service Pack 1 Build Architecture x86 Build Architecture Info GenuineIntel family 6 model 23 stepping 10 | 2 Crash Reason EXCEPTION_ACCESS_VIOLATION_WRITE Crash Address 0xb2d5004 App Notes AdapterVendorID: 0x10de, AdapterDeviceID: 0x06eb, AdapterSubsysID: 02331028, AdapterDriverVersion: 8.15.11.8621 D3D10 Layers? D3D10 Layers- D3D9 Layers? D3D9 Layers- Frame Module Signature Source 0 gkmedias.dll `anonymous namespace'::mono_to_stereo<float>(float *,long,float *) media/libcubeb/src/cubeb_wasapi.cpp 1 gkmedias.dll `anonymous namespace'::refill(cubeb_stream *,float *,long) media/libcubeb/src/cubeb_wasapi.cpp 2 gkmedias.dll `anonymous namespace'::wasapi_stream_render_loop media/libcubeb/src/cubeb_wasapi.cpp 3 msvcr100.dll _callthreadstartex f:\\dd\\vctools\\crt_bld\\self_x86\\crt\\src\\threadex.c 4 msvcr100.dll _threadstartex f:\\dd\\vctools\\crt_bld\\self_x86\\crt\\src\\threadex.c 5 kernel32.dll BaseThreadInitThunk 6 ntdll.dll __RtlUserThreadStart 7 ntdll.dll _RtlUserThreadStart More reports at: https://crash-stats.mozilla.com/report/list?product=Firefox&signature=%60anonymous+namespace%27%27%3A%3Amono_to_stereo%3Cfloat%3E%28float*%2C+long%2C+float*%29 https://crash-stats.mozilla.com/report/list?product=Firefox&signature=%60anonymous+namespace%27%27%3A%3Arefill%28cubeb_stream*%2C+float*%2C+long%29 https://crash-stats.mozilla.com/report/list?product=Firefox&signature=%60anonymous+namespace%27%27%3A%3Arefill_with_resampling%28cubeb_stream*%2C+float*%2C+long%29

Comment on attachment 786295 [details] wasapi-formattag (Attached the patch to the wrong bug)

According to crash-stats, this seems to have been fixed by the recent changes to the WASAPI cubeb backend.