It's better to be smaller, because even if your own mailbox supports a maximum single attachment of 40M, the enterprise you want to send may not be able to support such a large attachment, so make sure that the enterprise can receive it and try not to. The best way is to upload the video to the big video websites such as Tudou and Youku, then choose not to make it public, and finally link the video address inside to your resume. Those companies can see your work by opening your resume.