This is directly from the tivo.com supporrt site.....
How to prepare MPEG-2 video files for transfer to a TiVo DVR using tivo desktop 2.2 or later:
Use a standard personal editing tool such as Sonic MyDVD, Adobe Premiere, or
Nero to prepare a final cut of your video
Use the export/save as feature and choose MPEG-2 format. This is the standard format used by DVD players
Find the MPEG-2 encoding options and set them to the following parameters to ensure proper transfer and playback on TiVo DVRs:
Resolution 720 x 480, 704 x 480 (D1), 544 x 480 (3/4 D1), 480 x 480 (2/3 D1), and 352 x 480 (1/2 D1). The higher the resolution, the better the video quality and the larger the resulting file, which means longer transfer time and more disk usage on your PC and DVR.
Bit Rate 1 – 8 Mbps. The higher the bit rate, the better the video quality and the larger the resulting file. 4 Mbps is recommended for high-quality video.
Frame Rate 29.97 (standard NTSC). Do not try any different frame rates.
Aspect Ratio 4:3 (recommended) or 16:9
Audio MPEG-1 Layer 2 for TiVo DVRs without DVD; AC/3 (Dolby) for TiVo DVRs with DVD.