If you do change the pixel aspect ratio to something other than square you will have to change the frame size as well to compensate. Typically it will be 1080 p or 4k and in the future, it may be 6k or 8k now for the pixel aspect ratio this can get a little complicated to explain so i would always just recommend keeping it as square pixels which mean each pixel is as high as it is wide and then that way you don’t have to worry about the pixel aspect ratio as it will always be square so then you just focus on the frame size.
Next in the video section, we have our frame size this is our resolution so right now we have it set up as 1920 horizontal by 1080 vertical this is known as 1080 p or full HD and you can enter the frame size for the footage you’re working with. The exception to that being if you filmed in slow motion if you filmed in slow motion you want to make sure that your sequence is set up to what your frame rate will be when you finally export the video.
This is where we select our frame rate so if you have footage filmed at 30 frames a second or 24 frames a second 25 or in our case 23.976 that’s what you’d want to select because you always want to match the frame rate with your source footage. However, I prefer to use the custom option, and that way I can customize it the way I want down below next for the time base. There are many different options in the editing mode up here. Let’s go to the top into the area folder and we’ll select the 1080 px folder and then in here we’ll choose the 23.976 preset and then we’ll go to the settings tab here in the settings tab this is where you can change all of the settings such as the time base the resolution the pixel aspect ratio, sample rate, and the preview format. It will work however I always recommend to create your own presets that way you know exactly what you’re working with and you also understand the reasons for the settings because ultimately that will make you a better editor over time.
Now in order to get this custom folder you need to use one of the existing presets that come with premiere pro and then from within the settings tab that’s where you can change the settings for whichever preset you choose and from there you can save your own custom preset that matches the source footage that you are working with I’m sure for new editors when they’re just starting out in premiere pro they pick one of these default presets and that’s totally fine. At the very bottom you’ll see that there is a custom folder. Then the new sequence panel window will open up and you’ll see that we have many different presets that come with premiere pro. So with premiere pro open let’s go up to file > new and then select new sequence.