As someone who does a fair amount of post-production and optimization of videos for the search engines, I often find that professionals in both camps – the videographer and the video search optimizer – don’t always work as closely together as they should.
It is common for me to receive compressed video files from firms that may do outstanding production work, but pay no attention to the recommended compression specs from popular video search engine sites. The end result has led to several bad situations. For instance, a video file which may have looked and sounded great in its original format was left with choppy video and garbled audio quality after being compressed for online viewing.
Other times, videos not properly compressed and bloated in size will take up huge amounts of transfer time or are too big to upload altogether. When the video search optimizer fails to understand the tradeoff between faster encoding operations and the best video quality, or how to communicate the proper specs to the video producers, he or she will certainly be the one to suffer – both with having a substandard video product to optimize, and having much less time before project deadline to complete the work.
Whatever production format a professional search optimizer works in – be it video, podcasts, or Web sites – it is important to have some knowledge and understanding of the production side. A search optimizer doesn’t have to be a video production expert, or even be directly involved in the creation of the video itself (although it’s an advantage to at least have some experience).
But all professional search optimizers working with video – whether utilizing a professional video editor or doing the editing themselves – should know how to achieve the best video quality and the smallest upload possible. It’s also advantageous to know not only the required uploading specs for each video search engine, but how to go even further than the stated requirements to achieve the best balance between file quality and the smallest upload possible. This is especially important when working with large files or a large number of files.
Core Production Elements
Listed below are some core production elements search optimizers should consider in advance when dealing with major video optimization projects:
- Video quality – How good does the video appear and sound on the intended interface? (This can be your Web site or a 3rd party site, including a video search engine.)
- Quantity of data – What is the total file size acceptable for upload? Is the bit rate acceptable to the video search engine and the intended audience so it doesn’t appear choppy or have to be buffered? (Buffering will cause pauses or drops in the video streaming.)
- Compression algorithms – How well is important video information kept, and how is information indiscernible to the viewer discarded?
- Delivery scheme – Does the video search engine link directly to the source you have up on a Web site or server, or will you need to upload the videos to the video search engine’s own server (which will likely go through a codec)?
- Time – Video compression can take a considerable amount of time, especially when you factor in larger file uploads and multiple file formats. With a sizeable video project, does your timetable allow you a good deal of hours, or even days, just for video compression?
Understanding Video File Optimization for YouTube
YouTube is an excellent example for understanding this process, and the best place to start. As the most popular and accessible video search engine today, it has an easy-to-use interface and allows for direct video uploads. (Meaning, it’s not a requirement to create a video RSS feed, hosting all of the videos on your own Web server.) The tradeoff is that YouTube doesn’t actually display the original video that you submit. It uses a video “codec,” which is software that compresses the digital video.
Therefore, no matter how you send it, some of the data in your originally submitted file is going to be lost. The question is how much, and that depends on how closely you can match the video compression settings on your own software to the YouTube codec. The only problem is, YouTube considers its codec to be “proprietary information” and will not give it out to anyone.
Not to worry. YouTube provides basic information on its site suggesting technical specs for users’ videos. Any basic compression software (such as QuickTime Pro), and even some free programs, can compress your video with YouTube’s short list of recommended settings, shown below:
- Format – MPEG4 (Divx, Xvid).
- Image size – 320×240 pixels
- Audio –MP3
- Frame rate (aka, “keyframe frequency”) – 30 frames per second
- File size – 100 megabytes (MB) maximum.
- Length – Ten minutes for general accounts. For accounts in the partnership program, there are no time restraints, but the length must still fall under 100 MB in video file size. (Currently, the partnership program is only available to YouTube’s professional partners and selected content creators).
“Best” Video File Optimization for YouTube
Video search optimizers can balance their video quality and shorten compression time on YouTube with the additional encoding parameters shown below, provided to me by a YouTube spokesperson.
Audio encoding
- Data rate – 64 kbps (kilobits per second). Generally, the data rate is probably your most important overall parameter for video file optimization. The data rate affects the final quality of your movie, the file size, and the playback method for effectively delivering the movie
- Channels – Mono. (Not stereo. If you have Web video, you’re not going to be listening to stereo. And if you are, you’re on a computer, so it’s really not going to be that discernable.)
- (Output) Sample rate – 44.100 kHZ with MP3. The sample rate is the number of audio samples per second that are contained in the final file. Higher sample rates produce better quality audio with correspondingly larger files. The MP3 default sample rate is 44.1 kHz, which is also the sample rate of audio CDs.
Video (encoding)
- Data rate – 192 kbps
- File format – MPEG4 with H.264 compression. The H.264 compression scheme is available on very affordable compression software such as Quicktime Pro, and pretty much on all up-to-date professional compression software products.
Working with Video Producers for Optimizing Online Videos
The tips below apply when optimizing for video search engines and also when hosting the video on your own server or Web site:
- Contact technical support – Contact customer service or technical support for both the compression software company and the video search engine. Request to have your file compression questions answered by the product manager or a software engineer. (Yes, it does help when you have the advantage of saying you’re writing a column for a major online publication.) While the video search engine people will very likely not share with you what codec they use, the software companies may be doing lots of testing on the video search platform, and can have a pretty good idea of how to help you set up a “pre-set” in their software, which will more closely mirror the video search engine codec.
- Review your compression software – If you are working with a videographer, find out what compression software he or she is using, and its capabilities. On the professional level, I work with both Sorenson Squeeze and Autodesk Cleaner, which are both outstanding products. (They also provide automated FTP upload as an option, which comes in especially handy when you need to run the job overnight.) If the job involves taking video off of a DVD or CD, I use and recommend Miraizon’s Cinematize Pro.
- Run it as a single task – Compression times can slow down significantly, or even stop altogether, when you run other applications often. The ideal setup is to have a stand-alone computer just for doing compression work. (Having a good graphics card, CPU, sizeable hard drive, and lots of RAM are highly recommended.) If you don’t have a stand-alone computer for the work, schedule the compression to run when the computer is not in use (like overnight).
- Do at least one file test – If you plan to upload only one video, test out a segment of the video – 10 percent of the total length, or 30 seconds minimum, is a good measurement. You certainly don’t want to compress a bunch of files and find out none of them are what you intend for file quality. See how long it takes an average file to upload. Factor in the compression time and the upload time for that piece, so you’ll be able to estimate the total time involved for your entire project.