This is the second time I fall into this problem so i decided to blog it !
We were developing a service to permit users record, with their webcam, online videomessages and send them like MMS (multimedia message for mobile) directly from the site.
I was using the Flash Communication server, but I needed to create a batch for converting the FLV files in AVI format. So I downloaded the swiss
army knife of video tools, the ffmpeg free tool, and I used it to develop a batch to execute the operations automatically.
All seemed to work when .....
I surprised that the FLVs audio were lost ! It was due to the audio codec, the nellymoser. It's not an opend format, but it's a third-party codec (Sorenson).
I thought it was a bug but reading and documenting from the official documentation :
" .....cut .... The audio and video formats used within FLV are the same as
those used within
SWF. The FLV format, like the SWF format, is an open standard documented by
The DefineSound tag defines an event sound. It includes the sampling rate,
size of each sample (8
or 16 bit), a stereo/mono flag, and an array of audio samples. The audio data
may be stored in
- As uncompressed raw samples.
- Compressed using an ADPCM algorithm.
- Compressed using MP3 compression (SWF 4 or later only).
- Compressed using the Nellymoser Asao codec (SWF 6 or later only).
I deciced to contact Macromedia and spoke with technical engineers about
how I could solve my problem importing these flv into flash.
But I only received the sad confirm that this is not possible :( .
This is the what Brandon Purcell @ Macromedia and Chris Hock @ Macromedia said :
> there is currently no way to extract or convert FLV files into any other audio format.
They adviced me to contact Sorenson.
I contacted Sorenson regarding the NellyMoser codec to ask for some info and the possibility to pay a fee for the codec.
Sorenson pretended something along the lines of several thousand dollars plus restrictions that required profit sharing and/or more thousands. In addition, we would be unable to share the technology we build or make available as a service online...
So, I derive:
FLV is a proprietary format and not an open one !
Hope things will change with next version !!