youtube/google flash videos play fine for me by:
1) adding ;FLV to the Extension List in in_dshow config (prefs > plugins > input),
2) using the FLV Splitter to demux, and
3) using ffdshow to decode.
Yes, make sure ‘FLV1’ is set to ‘libavcodec’ in:
Start > Programs > ffdshow > Video decoder config > Codecs page.
To install the FLV Splitter, extract it to your %system% dir, then go to:
Start > Run
Type: regsvr32 FLVSplitter.ax
Hit Enter
(note: you might need to install 7Zip to extract from .7z)
More info here
Note: %system% refers to wherever the system dir is for your Windows OS.
eg. the default for WinXP is usually “C:\Windows\System32”
for Win2k it’s “C:\WinNT\System32”
for Win9x/ME it’s “C:\Windows\System”
etc
Also note that the FLVSplitter linked to above is for Win2k/XP/Vista.
If you’re using Win9x/ME then see here:
http://www.inmatrix.com/zplayer/formats/flv.shtml
ps. for GVI (google video) just use GVI2AVI (more info) to automatically strip the “goog” info out of the headers and change the extension to .avi (note, requires .NET Framework 2.x to be installed).