Hello again Samuel!
Please download the project here:DOWNLOAD
Everything that you requested is in there now.
First, notice that the captions are draggable.
However, the resizable plugin that you were attempting to use will not make the text resizable. Think about it for a minute. The resizable function was being applied to the #subtitle div. So what is resizable? The div itself is resizable -- not the text. The size of text within a div has absolutely dependence upon the size of the div itself. You can make the div as big as you want or as small as you want. It will not change the size of the text.
This goes for all container elements. Changing the size of the element with resizable will not change the size of the text content within the element. So the resizable ui pluggin will not work for that purpose.
Therefore, I implemented two buttons. You can, of course, reposition the buttons, rename them, etc. You can use them to make the caption text larger or smaller.
For the font and colors, they change as you select new fonts/colors. Some of those fonts are not web-friendly fonts. And some of them have very little difference between them. But the font change is working. And so is the color changes.
I put a "None" button next to the background color. You can select a background color for the captions (although the captions have a transparent background by default). But there is no option to select "transparent" in a color selection. So I added that button for when you want to remove the background color after it has been added.
I removed the transcript box and added the 8 lines instead. Now, if you center the captions to the left or right margin of the video, the captions will trail off video because some of the lines are far too long to have the captions centered on the edge like that. You will see that when you select 8 lines, it repositions the captions to generally the area you specified.
Look at lines 247 and 248 of your player file to view the position settings for the 8 lines. Change these values in order to position it exactly where you want it.
I apologize that this took a little while. It was actually a fair amount of work. Let me now if you have any questions.
Please remember to rate my answer. And please remember that if you have any questions involving this code without adding additional code/features, you can always ask follow-up questions on this thread.
Thank you so much and have a wonderful day!