i want to send a video from iPhone but resolution is poor

Hello Mark,

Thank you for the details of the issue you are experiencing when sending a video from your iPhone.

When sending a video using email, iMessage, or MMS on your iPhone, the quality of the video will be reduced so that the message can be transmitted. If you need to share the video with a higher resolution, you can upload your video to YouTube, which will support the HD resolution:

When sharing your finished iMovie video via email, iMessage, or MMS (iPhone 4 or later), the Camera Roll scales down and compresses the video in order to improve upload performance. If you exported your movie from iMovie in HD resolution when sharing to YouTube, you can select whether to share a standard definition or HD version of the video.

Regardless of how you share your finished movie, the original full-resolution version remains in the Camera Roll, and you can transfer this version back to your computer when you connect your device. To do this, follow the guidelines in Copying personal photos and videos from iPhone, iPad, or iPod touch to your computer.

Find the full article here:

iMovie for iOS: Why are videos shared through the Camera Roll lower resolution?

http://support.apple.com/kb/HT4237

Thank you for using Apple Support Communities.

Best,

Sheila M.