Optimising Video for Web & Mobile

Recently we've been confronted by a number of clients who haven't been used to encoding video (rather they have depended on server side encoding for their content).

Encoding is an art, not a science, and just like movies used to have graders, modern video production companies should have encoders who are skilled in optimising content for delivery over the internet to the web and mobile.

This is a field where drop downs in Final Cut Pro and a little knowledge are hugely dangerous things. The value of a well encoded video over a badly encoded one is immersurable.

And saying that 'YouTube does it well' is disengenious. YouTube encodes for a particular delivery profile, which does not necessarily optimise for mobile, set top boxes or platforms like Facebook.

But, as a broad guide, we would recommend using Handbrake, which has versions for Mac, PC and Linux.

After much recent experimenting we can barely see a difference between a 500Kbps and 2Mbps delivery using the following settings:

Container: MP4
Picture:
Width: 720
Height: 400
Cropping: none
Aspect Ratio: preserve
Anamorphic: none
Modulus: 16

Video Filters: None

Video: H.264 baseline using MPEG4 part 10 (not 2! And not Ffmpeg MPEG4 - this may result in either no video appearing in some browsers, or much lower quality)
Framerate: as source
2 pass encoding (takes more time but does make a difference of around 15% in quality we estimate)
Avg bitrate: 500Kbps

Audio: AAC (faac) Dolby II ProLogic 64Kbps 44.1 Mhz

Select web optimised or fast play or make sure Moov atom is at head, along with all metadata
Select streaming over download mode for scrubbing
Enable 5G Select No-DCT decimate for Android playback

This video will deliver HD over very poor bandwidth to most contemporary devices.

Codec Roundup

Perhaps the most confusing aspect of online video is the formats to use.

Here is a quick roundup of those currently available:

H.264 - also called 'MPEG4 and 'MP4'. This is a very long standing standard that has recently become de facto for the delivery of on demand content over the internet. It is a codec (MP4 is a 'wrapper' or 'format' and can also be played in other formats such as .FLV, MOV and even .WMV), and has good encoding, especially at high data rates. There are other advantages: this is the only format Google currently indexes (although they have recently announced that they will not play this format in future releases of their Chrome browser in order to favour their own 'WebM' codec). This format plays on iPads and iPhones and can be made to play on Android devices. It is also now largely supported by IPTV devices such as set top boxes. Overall, it is by far and away the best codec to use if you want widespread distribution. The downside is that it is 'owned' by a consortium of very large companies, although they recently agreed to make it freely available to all but the largest commercial users.

H.263, also called 3GP, is a codec that was developed for mobile devices. It is still used on older phones and on platforms supported by Blackberry and Nokia.

Ogg Theora - is a very old and largely unloved codec that is 'open source'. The quality is poor and support is patchy at best.

WebM - In 2009 Google purchased a company called On2, who were responsible for the codec at the core of the delivery of most Flash video (FLV). These codecs carry the VPx lable and VP6 and VP7 are what you will largely find as the formats of most current videos on the web. However, these are quickly being deprecated to H.264 (see above) and to VP8, or WebM, which is a codec that Google has ostensibly 'open sourced', but which is almost totally unsupported at the moment by anyone else.

VPx - On2 was the company that developed the core codecs used by Adobe Flash and as such has had a core role in the development of video over the internet. On2 was acquired by Google in 2009 and its codecs are no longer supported, although widely used.

VC1 - this is the core codec developed by Microsoft, and was, for a long time very popular since it was the only codec that came with a digital rights management specification. When Microsoft went on to develop the Silverlight development platform it deprecated VC1 and now sees H.264 as its core codec.

There are a number of other, largely proprietary, codecs available, for example those from Move Networks, whose assets were recently sold EchoStar, but none have achieved mainstream adoption.

Welcome to About Internet TV

This blog, or wiki, has been set up to provide a source of advice for anyone involved in setting up, using, or managing TV or video services over the internet.

The team at About Internet TV come from a broadcasting background, and we've been involved in delivering video over the internet since technology first made this possible in the nineties.

As a result we have a wealth of experience, and we hope that this will be of benefit to you.