I am familiar with the concept of Drop and No Drop frames and understand what it means. The bit I am puzzled over is that when I come to write a DVD of my production I have a choice of Progressive, Drop Frame or No Drop Frame.

Does using Drop Frame or No Drop Frame make any difference to the output quality on a DVD or is it simply a Timecode thing. I have burned DVDs using both settings and I can't see any difference.

For those interested I have found an excellent formula for converting HD to SD. using a Matrox RTX2 card.

Shoot footage in progressive mode (24, 25, 30, 50 or 60p)
Open a new HD timeline to match frame rate
Edit footage as normal
Export the footage as a Matrox AVI file using NTSC or PAL 1440 x 1080p (full HD is not supported but you can use 1920 x 1080 footage in this setting)
Set the Configure to 100% quality
Click on the small flyout button and select Maximum Render quality
Export the video

Create a new Matrox SD time line 486p @ 23.98 or 29.97p
Import the footage you have just exported and select Scale to Frame
Export the time line as a MPEG2 DVD file using Progressive
Maximum render quality 5
Min Bit rate 2.8, Target 7, Max Bit rate 8
Burn DVD

The final quality is outstanding, certainly the best I have achieved to date

Drop and non-drop are just timecode references. Nothing more.

Thanks Perrone, just as I thought.

I just wondered why this choice is available when you output a MPEG2 file for DVD