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Untangling the knotty myths of video compression

Zena Hirsch
September 28, 2015 by Zena Hirsch Staff

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!

35 Comments

a&b

Soooo.... is there a way to maybe thing of making the Myth #5 possible by giving a file size-limit and bit rates limits... then we could avoid a second compression ?

Zena Hirsch Staff

There's a bit more to the playback requirements besides file size and/or bit rates. Even if we could provide the full list of requirements (which, by the way, changes frequently), we'd still have no way to confirm that a file meets each one of those specifications upon upload. That just isn't technically feasible, unfortunately.

a&b

I appreciate your fast response, but technically impossible... I don't believe into ipossible. It might be hard but not impossible.
What if there is a plugin that we could compress our Prores videos BEFORE uploading it to vimeo... or some kind of stand alone little "converter" using the same techniques you are using Online ?
That way we could even upload from that app/program so Vimeo will understand that it dosen't need to be compressed a second time.
:)

Could that be an option ?

Vivid Peak Creative Premium

Zena didn't say anything about it being impossible. Zena simply said it's not technically feasible. There's a significant difference between possibility and feasibility.

a&b

Thanks... hmmmm... you are really helping it right now. ! Next time I will read every definition of the dictionary to make sure of each words meaning.

Ricky Norris Plus

do you have any insight on grain with vimeos compression? I get some really nice images with film convert but it all gets squashed away in second compression

Zena Hirsch Staff

Hey Ricky, we don't explicitly filter out grain in our compression process. My advice would be to upload the least compressed source file possible (within the constraints of our weekly quota), so that we have the highest quality file possible to work with.

Gerry Sorensen Plus

I'm going to be recording my videos for upload in my new iPhone (just was released). Does the iPhone record with the H.264 / AAC you were speaking of? I will edit them in iMovie. I am a kindergarten level here and have no idea what I'm doing...

a&b

if you can export following the compression guides it should be fine.
look in the FAQ, there is something about it.

Justin Ruggles Staff

iMovie has a share to Vimeo option in the File menu, which is probably your simplest choice

WEIRD LIFE FILMS ▲ Plus

Hi Zena,

Is visual complexity (in myth 3) based off an algorithm? Or does someone at Vimeo have the pleasure of watching every video uploaded and allocating higher bit rates to some than others?
Are certain users given advantages over others? (IE: Pro vs. Plus vs. Regular?) Possibly something to consider for paying Vimeo users. Lookin' to keep that film grain nice and sharp!
Cheers!

Martyn Randles

Hi Zena, thanks for a great post :)
I've always kept a text document open on one of my spaces which contains the Vimeo compression guides (I'm a Mac man, not sure if PC's have this feature? ("ctrl" & "arrow"). I have always found this very helpful as my first exported video is always max quality, file size etc., which I then archive for myself. This gives me a good idea of the size of the file. Then the 2nd export is the one I aim to get uploaded to Vimeo & you're excellent compression guidelines have helped me to get great quality videos uploaded using my free account & 500mb weekly limit. I'm a final cut express4 user, running Mac OS 10.6.8 on iMac, can't upgrade yet as I can't afford to upgrade all my software, it's not broken so I'm not wasting cash I don't have spare & I'd rather save up & spend it on a Vimeo Plus account as I was lucky enough to get the chance to try a free trial & it's amazing, I'm just waiting for my birthday to treat myself :)

Martyn Randles

Hi Alex & all at Vimeo :)
Wow! I'm actually lost for words...thank you so very much for this most unexpected act of random kindness. You have moved me & touched my heart by this very kind gesture. I can't explain how it makes me feel as I'm in shock, but I'll try to pinch myself just to be sure that it's real...yep, you really have upgraded my account to Plus! Thank you so much, I shall have to plan a proper thank you now...but for now I'll just act like a complete idiot & say thank you again as I can't think past the massive smile you've put on my face & my cheeks are starting to hurt from smiling now :) thank you Vimeo, erm, I've already said that...I feel like I've won an Oscar :) lots of peace, love & goodness right back at you, martyn xxx

Alex Dao Staff

You're so very welcome, Martyn! All we ask is that you go forth and make some great videos :D

VideoTeppisti

Thanks for that, this thing was kinda necessary, one further question tho:
Will this details preservation higher bitrate take care of the filmconvert noise too? Cause normally h.264 phucking kills all that beauty...

VideoTeppisti

maybe I can make use of this:

"Hey Ricky, we don't explicitly filter out grain in our compression process. My advice would be to upload the least compressed source file possible (within the constraints of our weekly quota), so that we have the highest quality file possible to work with."

vrajcula Plus

Hi Zena - about to buy a HD video camera for my sports work. Will it make a big difference with the uploads to vimeo... will the final be crisper and cleaner?

Michael "Blue" Markowski

Hello Zena… This explanation of Vimeo's compression policies was very useful & informative… Thanks… MM

Georgios Cherouvim Plus

Very insightful article.
It was asked before and I am curious myself, as to how the bitrate is adjusted from your end based on the visual complexity of the video (myth 3).
I have a short animation that I am about to release online, for which I've done several tests to make it look as good as possible through vimeo. Unfortunately it has a short part where the image breaks into separate lines, giving the codec a very hard time and makes the image look very blocky.
Is it maybe possible to increase the bitrate in specific segrments?

helmingstay Plus

This. The lack of publicly available details on vimeo's backend bitrate allocation algorithm makes this a difficult process for creators - a long cycle of trial & error: compress, upload, view, repeat.

Live Streaming Pros Premium

I really hate that there's nothing online that really helps explain the actual settings from camera to upload for best results. Everyone seems to give some information, but not in depth. I have my cameras set one way to record...and then I have to change all those settings to export and upload...do you guys have something available that shows the best camera settings for the best outcome to then edit and upload?

Compression is one of the hardest things we deal with as a video production team. We have people complaining about our file sizes for their iPods, so we have to release 2 versions of every video...one for our old school iTunes subscribers, and one for our HD crowd...I just want to be able to give them the best quality at the smallest size and I struggle finding that.

Thanks for the post!!! :)

Fried Canvas Studio

Ca you improve a little bit the quality? so we can export almost uncompressed and Vimeo compress less...can we do that? what about 4k like youtube? I have diffeent accounts here...can you please answer this?

Thank you very much!

Thanks!

Alistair Eagle Plus

Zena, can't you just provide an upload option button that just plays back the file as uploaded and nothing else? I always upload a light-weight 1080p h.264 file. I don't want my clients to see anything but this file. Why waste the resources to reconvert it to different formats? If I use too much of my data it will be my problem. Then I don't have to wait for an unneeded "conversion"

Bret Battey Plus

This is a very important article. It clarified items I have been unsure about (and, as it turns out, misled about) for years. However, I only found this article via a Google search. I think it deserves a very visible link from the page that most users are going to get to by using the Vimeo menus: vimeo.com/help/compression

Rush Videos PRO

Bret, we found this by way of Google search as well for Vimeo compression. What we're unsure of is if Vimeo transcodes or compresses the video again, even after we follow compression guidelines, then why not just upload full res and let Vimeo do the lifting if you have a Pro account.

Mars Roberge

In general, how large is a 4k compressed feature film on Vimeo? Also, Vimeo keeps mentioning 4k in reference to the smaller UHD 4K but does it accept the true 4096 x 2160 size? I'm trying to figure out if I can upload a 4k film with a plus account instead of having to go to a Pro one.

Mars Roberge Plus

Hey Everyone. I've recently purchased a Vimeo Plus account so I could upload a 4k feature as a screener to festivals. I'm allowed 5 GB of space. Is this even possible??? My 4k 444 Prores uncompressed film (1 hour 54 minutes) came out to 5.83 TB. This is true 4k (not UHD). Then, using Media Encoder's 4k Youtube settings (they don't have a Vimeo 4k setting yet), it made the film 33 GB. A nice compression but still WAY too big for 5GB of Vimeo Plus space. I then took the 4k 444 Uncompressed ProRes and made an HQ ProRes 422 UHD file which was 500 GB. After using the 4k streaming setting from Media Encoder on the UHD version, it actually made it 0.1 GB larger than the original compressed for web file. Any suggestions? Help!

Anthony Donovan Plus

wow good luck Mars, hope someone answers. From the old FCP7 I recently completed a documentary ready to submit to festivals, but 182 GB .mov file and a 128 GB .mov file of same (LT) Pro Res. I just bought Roxio Toast Pro, I know that's not very Pro, but I felt I can't do the learning curve of Premiere just now.... I heard they have presets.... to Vimeo, to burn Blu-ray.
We'll see what Roxio Toast does... I'm stumped...

mauborba Plus

Vimeo is going down. Lot's of upgrades and all in the wrong areas. The streaming system is glitchy at best and the quality still sucks. Stop making excuses and go to work.

joel booska

I'll be honest, Vimeo has a long way to go as far as accesibility goes. Streaming player, without fail, always stutters and chokes, no matter my speed, system/device, location. Any project with a mere 60% addition of film grain is still a clustered mess of compression blotching, and to get great results it seems you have to just break outm the beauty dish and white backgrounds for exposure to soak your frame. Sometimes I think I should just keep the files at home and run em thru a projector, at least then I don;t have to pay a premium for a service that can't possibly offer near compression free streaming and the coding to deliver that stream unflawed, like the supposedly less spec'd out youtube can. Ugh.

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