YouTube Supported Video File Formats: For some reason, it's a little hard to find the list of supported video file formats for YouTube. This is what I finally found in their help library:
- WebM files - Vp8 video codec and Vorbis Audio codecs
- .MPEG4, 3GPP and MOV files - Typically supporting h264, mpeg4 video codecs, and AAC audio codec
- .AVI - Many video cameras output this format - typically the video codec is MJPEG and audio is PCM
- .MPEGPS - Typically supporting MPEG2 video codec and MP2 audio
- .WMV
- .FLV - Adobe-FLV1 video codec, MP3 audio
Source - Supported YouTube file formats - YouTube Help