In the timeline are there redlines across the top of the timeline? If so you have set the wrong project setting, or using clips with different parameters. If you have, press [Enter] and PRE will start to render them for preview. After that if you edit or add effects / transitions affected portions will go red again. Press [Enter] where you need to see a smoother preview.
If this is not your problem look into these:
Insanity is hereditary, you get it from your children
OK its been a week since I posted this. Adobe has one of the worst forum interfaces I've ever seen. I have to get my password and then change it every time I try to log in.
However, I do have a red line. So just where and what do I 'enter'? When I highline the clip? I the scene line? Time line? Yes, I did take several clips from three different cameras. I used a DV tape camcorder, a JVC HD camcorder and the video option from a Casio digital camera. None of these seem to be correct. I tried a 'new' Project name and I still had the old clips in he newly named project. WTF?
I tried a 'new' Project name and I still had the old clips in he newly named project. WTF?
Where are you seeing that "older" media, the Organizer?
Look in the Project Panel, and you should NOT have any of that older media. The Organizer shows what you have on the system, and not what has been Imported into the Project.
When mixing media, I think that you will be best served to do one separate Project per media type, edit that, and then Export/Share to a common format, say DV-AVI for an SD Project, and then Import those into a New Project.
PS - for Adobe Forum log-in issues, please post to the Forum Comments Forum, with all details of your accounts, and Adobe-Admin (John C), will help you sort that out.
>where and what do I 'enter'?
You start by knowing what codec is in the file
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037
What is a CODEC... a Primer http://forums.adobe.com/thread/546811
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037
Report back with the codec details of your file, use the programs below
For Mac http://mediainfo.massanti.com/
Once you know exactly what it is you are editing, report back with that information... and your project setting, and if there is a red line above the video in the timeline, which indicates a mismatch between video and project