Fix and improve PHP, javascript bugs on video creation site

Hi, I've a site that creates videos from the browser, I need to fix some bugs and make some improvements. Understand how it works first: We can add text and images on a canvas preview, those become animated so are like a SLIDE, then once we are happy with it, we go and record then we use something to record it and then MERGE the audio and create an mp4 file (ffmpeg). - Can't create videos when using special characters on the canvas (preview works but not rendering), eg: "I've" , I have to use "I have" instead, the ' character is one problem. - There is an option to hide an animated image from the preview and final video, but for some reason when selected, it mutes the audio of the item we are using. - A few days ago 2 radio buttons got hiden, we need them back - A few days ago we were able to upload our own images, you can still do it but then we can't drag and drop or use the add button, to the preview canvas like before so something happened. - If there is audio on the project, we merge all the audio using the time when is suppose to be played and at the end if there is background music we merged using 20% volume, for some reason just 3 days ago, all the audio went down to 20% and at the end of the video the background music goes up again!! so we need to check ffmpeg or somethign else that got messed up! - Need to resize and move some buttons up on one of the tabs, just tidy up, easy. I will provide mock up. - Sort images listing, for some reason some images are not tidy , they should be tidy when showing the folder content. - I will change some text and replace it for other text, I will send it to you to copy and paste so I don't need to mees up wit hthe source, I could but not. - I will change 1 url in the source, you just need to copy and paste it. - Speed up a bit the writing efect, just move some numbers up inside JS code. - Keep some text in text area memory when going back to it, right now when going back to that box is gone, need to type all again. - Fix problem with folders using space, for some reason we have images folder with a space in them but the fornt end can't display the content of them unless I change the folder name and replace the space with a dash or no space. - On a previous version we used cron jobs to call for rendering, then we avoided the crons and call it to work straight forward and use up to 4 rendering calls at the time from users, for some reason that script got lost, damaged , right now we need to find a way to render the videos as fast as before, so SHELL scripting and other solutions are welcome. Please read this: -You must know well how to use and create SHELL scripts and cron jobs alternatives. -You must have a bitbucket account and use GIT well. It must looks like a lot but I'm just being detailed, so only apply if you read all and you really can talk about it, that means you know your way on php and javascript and can take a few hours to fix those issues, no time waster or non experienced developers, if you know your way you can get all done in around 5 to 6 hours.