FLV / Spark / H.263
        FLV is an older-generation codec designed for Adobe Flash. It is comparable to MPEG4 / DivX / XviD and Theora. It is commonly only used in the Flash Video container and has been mostly replaced by H.264.
        
            Options
            
                - 
                    Quantizer (0 - 30)
 Set a specific visual quality (recommended). Default is 0.01.
 quantizer=10
 
- 
                    Bitrate (number)
 Set a specific bitrate to control file size. Default is 300000.
 bitrate=512000
 
- 
                    Pass
 Set the mode of operation for single or multiple passes.
                        - cbr: single pass encoding (default)
- quant: constant quality mode (recommended)
- pass1: first of two passes
- pass2: second of two passes
 pass=quant
 
- 
                    Threads
 Use multiple threads when encoding.
 threads=2