Transcoding FLVs recorded by Flash
When you record webcam video via flash player using the Microphone and Camera actionscript objects, the audio is encoded using the proprietary Nellymoser codec. This means that if you try and transcode the video to a different format using a lot of tools that supposedly support FLV, you’ll probably get the video but not the audio.
For a long time, the only solution was to license Nellymoser’s codec, which was both expensive and difficult to get your hands on, and if you google around for, that is probably what you’ll hear. There was even a bounty put out for people to crack it.
However, there is good news. For the past few months, FFMPEG
( http://ffmpeg.mplayerhq.hu/ ) has supported decoding Nellymoser. I’ve been happily using it for the past few months to convert webcam FLVs into MP4s, and it works great.
To see if you have the correct version of ffmpeg, run “ffmpeg -formats” and look for a line that says “D A nellymoser”, which means it can decode the nellymoser audio codec.
