Raspberry π

For a pause, put

import time

near the top, then insert

time.sleep(5.5)    # Pause 5.5 seconds

between the upload_video and update_status lines. It'll probably achieve nothing, but it's something I'd try out of curiosity.

For verifying that the upload_video step is successful:

response = api.upload_video(media=video, media_type='video/mp4')
api.update_status(status=tweetStr, media_ids=[response['media_id']])

On line one, you're uploading your file to Twitter, and the response (including a unique identifier for the media file you just uploaded) is stashed in the response variable. You need that ID because when you then send your tweet with update_status, you need to attach the file to your tweet, and you do that by passing the ID of the media file along with your tweet: media_ids=[response['media_id']]

To verify the media upload worked, I'd probably start by just printing out response['media_id'] and seeing if it looks sane. E.g.

video = open('5into15.mp4', 'rb')
response = api.upload_video(media=video, media_type='video/mp4')
print('media_id', response['media_id'])
api.update_status(status=tweetStr, media_ids=[response['media_id']])