How to convert .h261 videos to .m2ts format.
Converting H.261 Videos directly to Blu-ray BDAV Video Files (.f4v to .m2ts conversion) should be possible and quite straightforward.
Use one of several currently available video editing programs or converters, such as Freemake Video Converter or FFmpeg.
Program for multimedia streaming and conversion
One of the most popular and successful free video conversion softwares