Ever create an awesome video that looks completely off after uploading? Then you know how important video compression is and how complex navigating the settings can be.
Every day, Vimeo’s transcoding team deals with the intricacies of handling hundreds of different video (and audio) formats and codecs. We rely on an array of external technologies, from software libraries to web browsers. The ever-shifting landscape of bugs, regressions, and improvements makes our goal of offering the most cutting-edge video quality both exciting and challenging.
The struggle isn’t just on our end, however. Many of our members wrestle with compression settings in order to achieve the best possible quality on Vimeo. Where such complexity abounds, misunderstandings tend to arise. Below, I’ve curated a few of the top myths surrounding video compression and its role in the Vimeo workflow. (If you’re needing more of a brush up on the basics, read this.)
Myth #1: All videos must be compressed according to Vimeo’s compression guidelines.
There is a common misconception that following our compression guidelines is required in order to upload videos to Vimeo. The truth is, following these guidelines is not mandatory — although in most cases, it is recommended.
So if they’re not required, why does Vimeo have compression guidelines at all?
- To speed up uploads by reducing file size.
- To reduce quota use (determined by the source’s file size).
- To guide members toward solid compression settings that will look great on Vimeo.
It’s important to understand the role of compression when uploading videos to Vimeo. Compressing a video before you upload it is usually necessary because uncompressed files are large and can take an unacceptably long time to upload. Additionally, the larger your source file, the more weekly quota it will consume. You can get the most out of your available space by compressing your file appropriately.
These compression guidelines are not meant to ensure compatibility with our transcoding system. Videos don’t need to be encoded with the H.264 / AAC codecs in order to be uploaded to Vimeo. But the benefits of using the guidelines are often worthwhile — saving you space and time and precious sanity!
Myth #2: Compressing your video leads to the best quality on Vimeo.
Our compression guidelines are not a guide to improving video quality; they are a guide to achieving the best quality given the constraints of technology and time. The compression settings recommended in our guidelines are lossy (meaning some quality loss will occur), but for reasons explained in myth #1, this is usually an acceptable trade-off.
After your video file lands on our servers, another round of transcoding takes place. When transcoding video, a higher quality input leads to higher quality output. It’s best to start with the highest quality source file possible. In a perfect world, Vimeo would have access to everyone’s uncompressed source files. In a more realistic world, we recommend uploading the least compressed file possible, given your uploading bandwidth and available quota.
Myth #3: Higher bit-rate source files lead to higher bit-rate playback files.
Many users, in search of the best possible quality, will unnecessarily inflate the bit rate of their source file prior to uploading. Then, they’re stumped to find that the playback files generated by Vimeo are no larger than those made from their uninflated source file. This is because the bit rate of our playback files is not based off of the source file’s bit rate. Instead, it is based on the visual complexity of the source file. Video with choppy water, moving particulate, or quick pans are more visually complex.
A video with tons of visual complexity (see example above) will require a higher bit rate than others. Bottom line: regardless of the source file’s bit rate, a visually complex video will always be assigned a higher bit rate than a video with less complexity.
Myth #4: All types of video compress equally well.
Compression is not “one size fits all.” Vimeo’s conversion process is customized for each uploaded source file. The bit rate of our transcoded videos is based on the source file’s visual complexity (see: myth #3). We allocate more bit rate to videos with higher visual complexity.
However, there are limits to how high the bit rate can go — especially when preparing videos for online streaming — so for some extremely complex videos, quality loss may be unavoidable. To mitigate this, it’s best to upload the highest quality source file available.
Myth #5: If you compress your video “correctly,” Vimeo won’t need to convert it.
All videos undergo conversion after they are uploaded to Vimeo, with no exceptions.
Many Vimeo members incorrectly believe that the compression guidelines are equivalent to our playback specifications. This isn’t the case. The files that we generate during conversion do not follow the same specifications described in the compression guidelines (although there are similarities between the two).
Even if your video was somehow perfectly aligned to our playback specifications, it would still be necessary to convert it after upload. Why? There are several reasons:
- We generate multiple playback versions of your video, including an SD file, an HD file, and others. Having multiple versions of the video ensures the best quality playback across different screen sizes and bandwidths.
- There is no easy way to be absolutely sure that any given video meets our playback specifications. Re-encoding the file ensures that it will always play back correctly.
- Vimeo’s playback specifications are constantly changing as we adapt to improving technologies and add support for new playback environments.
p>We’ve now tackled some major compression myths, but if anything is still unclear or if you have any questions, please don’t hesitate to add a comment below, dig into our help forums, or shoot a note to the handsome and competent support team. We want to hear from you! It’s the collaboration between filmmakers and our transcoding engineers that makes Vimeo videos the most beautiful on the Internet!