Well going over what I do know, I recorded 5 videos all 12 seconds long and in all resolution options given. I wasn't even allowed to send them to myself via mms because the file size is too large. However in recording mode there's a "limit for mms" option which give a horrid resolution result but allowed me to send a 15 second video to myself. Under the the regular sms/mms settings I'm not seeing anything that changes length or size... Only manual or auto retrieve options. If you're getting videos sent to you from multiple people and they're all 8 seconds exactly then it's definitely your device. If it's just one person sending the videos to you then have them send a video to their self and see if they get the full video or 8 seconds. If they get 8 seconds then it's their setting they need to adjust but if they get the full video, again it's definitely your device. I'd say take it from there first then post results.