It seems to me that the original post on this thread got sort of hijacked. The point was that VLC saves a 0-byte file when you are saving to an FLV file, even when you are simply changing the wrapper to FLV. I can confirm this happens in v1.0.5 Goldeneye running under Windows XP Pro x64. I have an M4V file encoded by Handbrake (which VLC is perfectly happy to play); yet, when I use VLC Convert/Save to save it as an FLV with "Keep original video track" and "Keep original audio track" checked, the result is a 0-byte output file.
(1) The VLC docs say that VLC _plays_ FLV files via FFmpeg. So, you have to have FFmpeg installed for FLV PLAYBACK support:
http://wiki.videolan.org/Common_Problem ... .28.flv.29
(2) If you look at FFmpeg's file format support, you find out that it does NOT support OUTPUT to FLV:
http://www.ffmpeg.org/general.html#SEC4
So, it sure looks to me that VLC does NOT support FLV output, and therefore the FLV choice in the "Encapsulation" tab shouldn't even exist. It confused the hell out of me until I did the above research. An app should not provide an option which really does not exist, and then output an empty file with no error message. It's terribly confusing to the end user. THIS is the issue that the original thread poster brought up.
Note: Since I can imagine someone posting "what encoding were you trying to convert?" even though I'm just changing the file format, here's what's in the MP4 file (from Mediainfo):
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L2.2
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format version : Version 4
Format profile : LC
Format settings, SBR : No
Codec ID : 40