Multi-Media Compression
A Use-Case Scenario involving compressed video and image files.
I have a small Instagram account themed around my favorite beverage. I use this account to experiment with different types of media over the past year. Recently, I used it to test various compressed files to discover any new or hidden ways to post better quality content.
This project consisted of a research portion, a compression evaluation, and a final test.
Part One: The Research
I went searching online to find what types of media formats were supported by Instagram. Turns out, I was limited to a few kinds. According to this source, I could upload .JPG, .PNG, and .GIF files for images as long as they were smaller than 1080 pixels (px). For videos, I read that I could upload .MP4 and .MOV files with the same 1080 px resolution limitation. With this information, I created a plan to test multiple files in Photoshop and Encoder to find the best quality/size ratio.
Part Two: Compression Evaluation
Images
I used Photoshop to export multiple compressed photos and compared them to each other. Photoshop has three export options: Save As, Export As, and Save For Web. You’d think they’d combine these features into one, but they actually alter compressed images slightly depending on what you do, and they all have slightly different capabilities.
The Save As option allows you to save images in several formats and then gives you an option to change the quality of your image on a scale from 1 to 12. Save As is a great option if you want to save your image for a less common file format.
If you want a little more control over you compression, you can use the Export As feature. It gives you more options with how you want to export an image, like changing the image size. It doesn’t allow for exporting into as many formats as the Save As feature does, but you can use it to export .JPG, .GIF, .PNG, and .SVG files.
The last option you have is Save For Web. This also has limited file options, but you can compare quality right in the window. It’s by far my favorite feature about it.
You can adjust the quality of each picture and zoom in and out to compare quality. I highly recommend using this feature.
Video
Using Encoder, I compressed my original video file into several versions. I shot the video on my iPhone and edited it with an app called Splice, which compressed the file into 4k pixels. Unfortunately, due to my computer malfunctioning, I was only able to export 4 compressed files without Encoder crashing or the computer freezing. I compared these exported files on my Macbook, iPhone, and iPad. I came to the conclusion that, especially with video, finding the sweet spot between file size and quality can be attributed to many different aspects. The video file I found to have the best quality to size ratio was compressed at 1080px, a bit rate of 20Mbps, and a file size of 38.1MB.
Part Three: The Final Test
Now that I’d found which files had the best quality:size ratio, I tried to upload them to Instagram. I ran into some issues with posting my video from my computer. First, Instagram has a terrible desktop interface. I would get to a certain point in posting, and Instagram wouldn’t confirm that the video had been posted. When I clicked submit, nothing happened. So I had to upload with my phone. I tried to upload other video compressions, and they all uploaded perfectly fine. This seemed strange since some of the videos were much larger than 1080px and it was my first indication that Instagram was compressing my content.
With my images, I uploaded about 4 different compressions of the same image type (.JPG) and compared them on the app. To my dismay, none of them looked different from each other. This was another indicator that Instagram compressed my content again. I tried to upload .GIF and .PNG files, but Instagram rejected them outright.
Conclusion
I was sad to learn that Instagram compressed over my images and video after I’d spent the time finding the best versions of my media. I think they do this to prevent uploading and app loading issues, plus most users don’t want to post extremely high quality content. If I were to test this media again, I’d choose to use my own website where I had complete control over the content and I could measure load times and have more freedom to use more media formats.
Erin Hancock is a student in the Digital Media program at Utah Valley University, Orem Utah, studying Web & App Development. The following article relates to projects from the (DGM 2341 Course) and representative of the skills learned.
