Converting FLV to 3GP --> FLV Unrecognized?

[SnakeGirl]

i guess no one's gotten back to me yet about suggestions/recommendations for how to capture & download streaming video from the internet on the Mac so i've been doing a little poking around. i found a Firefox add-on that was able to download streaming video (from some websites, anyway) as FLV files. On 1 test file that was downloaded, i was able to convert it from FLV to 3GP format using ffmpegX. However, certain files that i thought i had captured & downloaded from other websites as FLV files didn't seem to be recognized by ffmpegX when i tried to select them as source files to be converted to 3GP. (When i drop the FLV files into the Source format area on the ffmpegX summary page/tab, the source format is flagged as Unrecognized w/the source video input field showing "[flv @ 0x4701fc]Could not find codec parameters (Video: 0x0004)" & the source audio input field showing "No audio". Since i am clueless about these FLV files, can someone perhaps enlighten me on why some FLV files are recognized by ffmpegX while others are not? If this is the wrong place to ask about FLV files & formats & streaming video capture on the Mac, if someone could direct me to the correct forum(s) &/or other resources so i can learn more about them, that would be greatly appreciated. (i've been sifting thru these forums to try to find out whatever i can about the topic, but a lot of what i'm finding seems rather technically obscure for a newbie & over my head.) Thanx.

[Case]

Not all FLV files use the same video codec.
The free and shareware encoders often use H.263 for video in FLV files, which can be decoded by ffmpegX. Some commercial (Adobe/Macromedia) video encoders (can) use VP6 as video codec. The developer of VP6, On2 Technologies, won't allow the open source community to include (independently developed) VP6 decoders in open source software.

So, while bowsers with the Flash Player plugin play FLV files with VP6 video just fine, there is no third party conversion software (without a license from On2) that decodes it, in fear of lawsuits.

Luckily, the new version of Flash Player (v9) does allow H.264, so the future looks a bit brighter, as more content will use H.264 in favor of VP6.