WMV is a streaming media format introduced by Microsoft, which is an upgrade and extension of ASF (Advanced Streaming Format) format. Under the same video quality, WMV format is very small, which is very suitable for playing and transmitting on the Internet. AVI file encapsulates video and audio in one file, and allows audio and video playback to be synchronized. Similar to DVD video format, AVI files support multiple video streams and audio streams.
WMV is not only developed based on Microsoft's own technology. Since the seventh edition (WMV 1), Microsoft has started to use its own non-standard MPEG-4 Part 2. However, since the ninth edition of WMV is an independent standard of SMPTE (42 1M, also called VC- 1), it is reasonable to believe that the development of WMV does not have its own proprietary encoding and decoding technology like MPEG-4. At present, there are 16 companies enjoying the patent of VC-1(April 2006), and Microsoft is also one of the companies enjoying the patent of MPEG-4 AVC/H.264.
Microsoft's WMV is still very influential. However, due to Microsoft's own limitations, its WMV application development is not smooth. First, WM9 is a product of Microsoft and must rely on Windows. Windows means that the decoding part should also have a PC, at least the motherboard of the PC. This greatly increases the cost of set-top boxes, thus affecting the popularity of video on demand. Secondly, the video transmission delay of WMV technology is very large, usually 10 second. Because of this restriction, WMV can only browse WM9 video files on the computer at present.
Wmv-HD is a video compression format created by Microsoft, a software giant, and is generally adopted. WMV as a file suffix. Its compression ratio is even higher than MPEG-2 standard, and it is also a 2-hour HDTV program. If MPEG-2 is used, it can only be compressed to 30GB at most, while if a high compression rate encoder such as WMV-HD is used, it can be compressed to less than 15GB, and the image quality is not degraded.
Based on WMV9 standard, WMV-HD is the latest version of video compression technology series developed by Microsoft. Although WMV-HD is a unique standard of Microsoft, it is rapidly popularized in desktop systems because it strongly supports WMV series versions in the operating system. In terms of performance, the data compression ratio of WMV-HD is the same as that of H.264, and its application fields are also very similar. Therefore, in the struggle for the dominance of the new generation of mainstream video coding standards, the two sides launched a tit-for-tat struggle, focusing on the next generation of optical disc specification "HD DVD" and digital microwave broadcasting and television.
Generally speaking, HDTV files use. The wmv suffix is compressed by WMV-HD.
At present, the DVD Forum has preliminarily approved Microsoft's MPEG-2, H.264 and WMA-HD as the mandatory standards of the next generation DVD, namely HD-DVD technology.