When prompting for video generation you can optionally choose to add a start frame, or both a start and end frame. These are images which you may have generated in Pencil or uploaded from an external source.
Start and end frames can be combined with a prompt and, as their names suggest, they will form the starting and/or ending frame of your generated video. This article will focus on the use of both start and end frames and provide a few tips to help you make effective use of them.
In order to access the start and end frame canvases you need to select 'Image to video' on the left hand side of your workspace. By default you will just see the 'Start frame' canvas visible, but you can reveal the identical 'End frame' canvas by expanding it just above the 'Prompt' box.
You will see that you can add an image by dragging an external one in or by opening the Asset Library and selecting one from there.
Top Tips for choosing effective Start and End Frames
Assuming you will be including a prompt that describes what you want to the model to generate between your start and end frames (i.e. how you want it to get from the start frame to the end frame) there are some things you may wish to consider from an image point of view in order to maximise the chances of achieving your desired and hopefully seamless video, transitioning between the start and end frames.
Avoid crowded and complex backgrounds. The model may find it challenging to generate smooth and coherent movement if there are many elements in the frame.
Ensure your focal point is consistent: The model will have most success if your focal point (e.g. a person) is consistent in terms of:
dress/styling
approximate placement in the frame
approximate size within the frame
Avoid trying to make too many changes between your start and end frames. This process works most effectively when focusing on one or two simple, main movements occurring between the start and end frames.
Take advantage of seeds when generating your start and end frames using Pencil's Image Generation. Using seeds allows you to take an image that you like, and may want to use as your start frame, and further prompt a variation of that image, which may provide a useful end frame.
Example
In this simple example I generated a head and shoulders head-on shot of a man with a yellow background, which I wanted to use as my end frame:
I took the seed from that image and used it when prompting for my start frame, which gave me an extremely similar looking man with the same t-shirt and background, but with more of a profile shot.
I saved the images to the Asset Library and added them to my Video Generation project as Start and End frames:
Using the simple prompt:
"Man turns from a profile shot to face the camera directly and smiles broadly. Camera remain in fixed position."
I was able to generate the following short, smooth clip: