AVI (Audio Video Interleave, file extension .avi) video files cannot be played in Nokia N97 or N97 mini device. The files need to be converted first to MP4 or 3GP video file format before they can be played. The conversion can be done for example with Nokia Ovi Suite or PC Suite when transferring the video files to the mobile device.
When using Nokia Ovi Suite, version 2.1 or later is needed for the video transfer. Copy the AVI video file to your Ovi Suite album, right click the video and select Copy to device. For more details, see Nokia Ovi and PC Suite instructions.
Note that the conversion of the video file format doesn't yet guarantee that the video can be properly viewed in your device. The video and audio codecs must also be compatible with the codecs supported by the device (see the product specifications for the supported codecs).