Files named C003.mp4 are commonly generated as raw video clips, and import issues in software like Adobe Premiere can often be resolved by renaming the file extension or transcoding with tools such as Shutter Encoder. Other interpretations of the "C003" code include JVT video coding standards, a specific Spanish public administration agreement, or Open Mobile Alliance technical documents. For troubleshooting video import errors, users can review advice at Adobe Community . Can't import MP4 files. - Adobe Community