vfw2menc.exe: OpenDriver() failed

[^rooker]

[PROBLEM]
I tried to encode VP6 Flash video files (.flv) with mencoder (Windows build rev 34401), but in order to configure the codec's settings, I called the "vfw2menc.exe" tool, as mentioned in the official mencoder documentation:

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vfw2menc -f VP62 -d vp6vfw.dll -s firstpass.mcf

I received the following error message:

vfw2menc.exe: OpenDriver() failed

[SOLUTION]
By default, the current Windows build of mplayer/mencoder comes with an empty "codec" subdirectory. I've downloaded the codecs from the mplayer website (filename: all-20110131.tar.bz2), and unpacked all files direclty into the codec subfolder.

This works fine for transcoding, but the vfw2menc tool seems not to find the DLLs, so I've changed to the folder where I've extracted mplayer - and also where vfw2menc.exe is located - and added the "codecs\" folder to the commandline:

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vfw2menc -f VP62 -d codecs\vp6vfw.dll -s firstpass.mcf

And voila: The VP6 codec configuration dialog appeared.

[^rooker]

...by the way:
In the original documentation, I wasn't completely sure how to use the .mcf files created with the codec-dialog called using vfw2menc, when doing a 2-pass encoding.
Thanks to a thread on the mencoder mailing list, from 2007, the answer is to use the "compdata" argument of the VP6 codec, like this (I'm quoting the example from the mplayer documentation):

For the first pass, use "firstpass.mcf":

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mencoder -dvd-device zeiram.iso dvd://7 -o trailer.flv \
-ovc vfw -xvfwopts codec=vp6vfw.dll:compdata=firstpass.mcf -oac mp3lame \
-lameopts cbr:br=64 -af lavcresample=22050 -vf yadif,scale=320:240,flip \
-of lavf

...then call the same line again, but this time with "secondpass.mcf":

Code: Select all

mencoder -dvd-device zeiram.iso dvd://7 -o trailer.flv \
-ovc vfw -xvfwopts codec=vp6vfw.dll:compdata=secondpass.mcf -oac mp3lame \
-lameopts cbr:br=64 -af lavcresample=22050 -vf yadif,scale=320:240,flip \
-of lavf

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