This post is the second in a series of three about media streaming. Previously, we provided a non-technical introduction to media streaming. In this article, we assess what file formats are available to stream media with.
For audio, MP3 is generally the format of choice as it is ubiquitous and widely supported, although the OGG or Vorbis format is gaining popularity amongst vendors because there are no patents restricting it’s use (unlike MP3).
With video, however, the choices are more complicated due to rapid growth and progress in the whole area of video delivery via the internet. The following are the more well known streaming formats available:
- Flash Video (FLV)
- Windows Media Video (WMV)
- QuickTime
- RealMedia
- H.264/MPEG4
Flash Video (FLV)
A popular choice because of the wide support for the Flash player in most web browsers. Flash also has the advantage of working on both Macs and Windows PCs. Flash Video is probably the most ubiquitous streaming video format, due in no small part due to it’s adoption by larger sites such as YouTube.
Windows Media Video (WMV)
WMV is usually successful in corporate environments where Microsoft technologies proliferate on the desktop. Outside Windows environments, the results can be less reliable. The situation with WMV is currently undergoing rapid change as a result of the release of Silverlight (a Flash competitor playback technology). The Silverlight player will be much more widely supported by non-Windows PCs (e.g. Macs). A variation of WMV called VC-1 is natively supported by Silverlight and this will make format selection less straightforward than it has been up until now. A number of larger media providers are planning to or already have adopted Silverlight rather than Flash.
H.264/MPEG4
MPEG4 is one of the newer formats and is likely to become popular because the footage is higher quality than Flash Video, however, the file sizes also tend to be larger and consequently slower for users to download. That said, many media owners have invested heavily into MPEG4 and are keen to avoid the process of converting (or ‘transcoding’) to a lower quality preview format such as FLV. There a re a variety of derivative formats that are specialised for certain applications, e.g. 3GPP which is MPEG4 optimised for playback on mobile devices. To further complicate matters, the Flash Player now supports direct playback of H.264 video as well as FLV.
QuickTime
This format is popular on Macs because support is built in and also with more sophisticated Windows users is less widely supported. QuickTime is a reasonable choice where the audience is composed of video professionals (e.g. for a production oriented DAM or Media Asset Management system).
RealMedia
Real were an early entrant to the streaming market but are currently losing market share, partly due to the high costs of licensing the server technology required to deliver streaming media in the various RealMedia formats.
Conclusion
If you need to deliver streaming video in the next few months, a choice of FLV or WMV is probably the two most realistic options. Vendors of more versatile Media Asset Management systems should also be able to support both (with intelligent switching based on the capability of the end user’s computer).
If you are considering a system that will be deployed towards the end of 2008 and persist for a number of years after that, H.264 and WMV/VC-1 needs to be seriously considered. Again, more powerful video oriented Digital Asset Management solutions will anticipate both technologies and offer support them equally. Daydream’s FocusOPEN Digital Asset Manager can support Flash, WMV/VC-1, QuickTime, MPEG4/H.264 and deliver via either Flash or Silverlight players.
As described at the start of this post, the streaming video landscape is currently changing at rapid pace. When deciding what DAM to select for time based media, it is vital to work with a vendor that understands the environment, can explain the choices to you without excessive jargon and has the flexibility to switch between the different competing technologies.
In the next post, we consider the main competing technologies for playing back streaming video.