HTML and CSS Reference
This may look confusing, but as you can see, most codecs have come and gone, much like many other
technologies, and for the remainder of this section, I'll discuss only the codec technologies that remain apparent in
today's market of HTML5 video, which are MP4 (H.264), WebM (VP8), and OGV (Theora). I'll exclude VC-1 because at
the time of this writing, no browser supports this codec/wrapper variation.
I'll now discuss probably the most popular video codec on the modern Web, MPEG's H.264. The H.264 codec is a highly
optimized codec that offers supreme compression with little quality loss to the overall video. H.264 can provide great
lossy quality at relatively low bitrates. H.264 comes with many adjustable parameters and features—so many in fact that
if you look up H.264, you will be amazed at what this codec is capable of doing. However, you need to be specifically
aware of its profiles, which are baseline, main, and high. Certain devices such as older iPhones and iPod touches can
support only a baseline profile, where other high-end devices, such as your desktop computer and Blu-ray players,
support main to high profiles. The profile's level is measured in a scale between 1 and currently 5.2, and as the profile
level increases, the bitrate and usually the quality do as well.
■ to learn more about h.264 video, i suggest reading the works of Fabio Sonnati at
H.264 is pushed hard by Apple, Microsoft, and various other large companies, and it's currently supported by
Apple, Microsoft, and Google in their respective browsers, although Google has mentioned that it will stop the support
for the codec in support for its VP8 alternative (more on this in the following section). However, as of this writing,
Google still supports it in releases of Chrome. In addition, Mozilla has even discussed supporting H.264 because of the
lack of support for its supported open source codec, Ogg Theora (more on this in the following section). H.264 also
has royalty-free open source variations on its sophisticated encoding algorithms called X264 ( http://x264.nl ).
Apple, which is a major supporter of the H.264 codec because, it's the only codec supported in its Safari browser,
recommends the encoding settings shown in Figure 7-4 for serving to iDevices via Safari.