Toshiba Camileo BW10 - output .mp4

[croarta]

I just bought a new camera – Toshiba Camileo BW10
Output format is .mp4
I film with TV OUTPUT: TV type: 16:9 and HDMI: 1080I and I use HD-SHQ
Video and picutre is amazing on computer as .mp4 format. Once i convert it to .avi quality is still okay ( i have to convert it cuz moviemaker doesn't allow .mp4) BUT when i put the same .avi clip in windows moviemaker and save the clip /using option – save as best quality (large)– it's so baaad + I downloaded those codes and still quality is changed.
So my question is – is there any free edit program for video ( I don't need any speacial effects or magic lol) wtih main transiton and option for adding music on movie clip that keep the same quality as it's filmed. Is there any program that it's okay with .mp4 format?
Thx a lot!

[Baldrick]

One thread is enough. https://forum.videohelp.com/threads/325716-I-lost-quality-with-windows-moviemaker-HELP?...20#post2017020