I download lots of live stream FLV videos and 99% of the time I by using a combinations of FLVjoint/FLVExtract/MP4Box and finally using Avidemux to edit (copy mode without the audio, no audio is needed) and the final video is in perfect form in mp4 format without audio (as stated earlier, audio is not needed).

Original T1.FLV
Format : Flash Video
File size : 1.79 GiB
Duration : 750ms
Overall bit rate : 20449985386

Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L3.0
Format settings, CABAC : No
Format settings, ReFrames : 3 frames
Codec ID : 7
Duration : 750ms
Width : 320 pixels
Height : 240 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 66.667 fps
Original frame rate : 20.000 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive

Step 1 - Original T1.FLV
Step 2 - Run original T1.FLV thru FLVExtract
Step 3 - End result is T1.264
Step 4 - Use mp4box.exe -add "P:\T1.264" "P:\New.mp4"
Step 5 - Use Avidemux to edit New.mp4

Now, with the above FLV, once I run it through FLVExtract, its NOT showing the actual frame rate of 20.00 (but showing frame rate of 66.667 in both actual and average) and hence (I guess) MP4Box wouldn't/couldn't process it (it actually crashed MP4Box when I "mp4box.exe -add "P:\T1.264" "P:\New.mp4"

What else can I do/use to correct the above FLV file before sending it to MP4Box?