"I was able to import my Sony Handycam DCR-SR100 mpeg2 files to iMovie, and it looks and sound fine. However, when I upgraded to Lion, I can use iMovie to view my source video on my laptop, I can see them but without audio." -Excerpted from Apple Support Community.
You may be also suffering from kinds of problems in importing your Sony Handycam files into iMovie? Here I would like to share two ways out.
It's known to all that iMovie'11 works better with more camcorder models than its old version-iMovie'08, iMovie'09. Firstly, check out whether your camcorder model is included in the list of camcorders supported by iMovie'11. Anyway, you'd better to know that iMovie'11 requires Mac OSX V10.6.3 or later with Intel PC, before upgrading to iMovie'11.
If your Mac runs with Power PC, OS is below 10.6.3, or your camcorder model can't be accepted by iMovie'11, you may have to convert Sony Handycam AVCHD/MPEG2 footages to iMovie.
Doremisoft Sony Handycam to iMovie Converter can easily convert any AVCHD MTS/M2TS or MPEG2 footages from Sony Handycam to iMovie supported file format like MOV or H.264. Then, you can further editing the generated files in iMovie. The Sony Handy Video Converter for Mac can be well workable with below camcorders:
Sony HDR-TG3, HDR-CX150, HDR-CX130, HDR-SR11, HDR-SR12, sony HDR-CS700V, HDR-XR160, Sony DCR-S68, DCR-SR42, HDR-CX11, HDR-CX12, HD DCR-SR60, DCR-DVD508, etc.
Download the trial version of Sony Handycam Video Converter for Mac on your Mac and run it.
Then, click "Add File" to load the Sony Handycam AVCHD/MPEG2 footages into the program.
Tips: If you have problem in playing or editing the Sony Handycam AVCHD or MPEG2 footages on PC, please refer to the PC version of Sony Handycam Video Converter.
The program has several optimal file format presets for iMovie. Click "Profile" button, select any file format as output in the drop-down list of "iMovie Video": "iMovie MOV", "iMovie MPEG-4", "iMovie AVI", etc.
Hit "Start" to launch the Sony Handycam to iMovie MOV or MP4 conversion.
When the conversion is done, run iMovie and import the generated .mov or .mp4 file to iMovie by clicking File > Import > Movies...