Accessing motion vectors using libavcodec

[aka_magnus]

First post for me so go easy :).

Could anyone tell me if there is a reasonably straightforward way of getting access to motion vector information using libavcodec assuming a video has been encoded using some motion compensation compression technique?
Thanks.

[Manao]

Without having to code : use FFDShow. It has a nice visualization option that allows to show the motion vectors of the codecs decoded by libavcodec.

If you needs something else : hack & slash in ffmpeg's source code. It's not that hard, and help can be provided on irc or on the mailing list.

[aka_magnus]

Thank you Manao. I hadn't seen the motion vector visualisation option in ffdshow before. However, I'd actually like to do some processing on the motion vectors to find shot/scene cuts. It looks like I will have to delve more into the libavcodec code. Thanks again and I'm sure I'll be back for more help soon.

Edit // Hmmmm, I forgot that libavcodec won't compile in VC++ and thats what I'm using. Is there anything in the win32 compiled libs/dlls that I could use?

Thanks

[aka_magnus]

I've been trying to see how ffdshow gets access to motion vectors when overlaying them on the video. I have done this by building a graph using directshow and trying to access the appropriate interfaces. I am totally at a loss though.

Can anyone please help?
Thanks