New video compression standard to challenge the test technology – video encoding
In recent years, digital media development needs of high-quality video, depending on the transmission channel, encoder and decoder for digital signal processing quality, this paper introduces the new MTS4EA Video Elementary Stream Analyzer can be used for the next generation and current video compression technology provides a flexible, upgradeable test solution to support MPEG-4, H.26x series and 3GPP standards.
Recent years, digital communications media, including cable, satellite, Internet, DVD, etc., and their transmission capacity has made rapid development, although the capacity is constantly increasing, however, these programs can provide the media channel capacity only slightly with two or more orders of magnitude, which for transmission / storage of high-quality uncompressed video, that was too small.
Now more channels on the number of mobile video, high-quality video, high-definition video, more strong demand for digital communications media, the growth rate of capacity can not satisfy the growth needs of the consumer expectations. Video shows how much bandwidth is needed?
In cable transmission, a good quality standard definition (SD) video (resolution 720X480NTSC or 720x576PAL), approximately 10-12Mbps bandwidth. If the same bandwidth to transmit the number of three or more channels is not better? To be the case, will give consumers more choice, service providers will be to bring more revenue.
If high-definition (HD) television what then? Transmission of a channel with a resolution of 720's HD programming (that is, 1280X720, progressive scan format) is a channel bandwidth of about SD programming 2.6 times, while the transmission of a channel with a resolution of 1080i (ie 1920×1088, interlaced format – this is also the majority of television region prepared to make the choice) of HD programming, a channel bandwidth is about SD programming 6 times. Program suppliers may increase in the SD programming on HD programs, but consumers are less willing to watch only the programs (also not willing to pay more for the HD). It would appear, if not in technology transfer and receive additional investment, the only option is to use a better video compression scheme.
Video compression is not new; it early in 1980 will have a H.261 video compression standard, which is designed for video conferencing applications, and the bit rate of 64kbps, as shown in Figure 1 . In accordance with the H.261 video compression standard, and its smaller screen size, frame rate being limited, however, it reflects the image compression was able to handle the capacity and available bandwidth can be achieved.
The evolution of standards Over the years, the video compression algorithm / compression standards in parallel with the development process of the two international organizations: 1.H standard, which is by the ITU (International Telecommunication Union) standard developed. 2.MPEG standard, which is by the MPEG committee and later by the lSO (International Standards Organization) approved standards.
As is expected, the new video compression standard is superior to older video compression standards, for the same image sequences, respectively, and H.264/AVC MPEG-2 compression standard to compare the results shown in Figure 2, which has improved compression ratio. What makes MPEG-4 has not been widely adopted? MPEG-4 part video compression can provide a good quality, was clearly beyond the early standard, but it has not been more fully utilized.
Of commercial applications,, H.26/AVC but over it, this is why? Have several reasons:
1.MPEG-4 standard is actually a very large and complex standard, it is composed of many parts: video, sentence structure, audio, system, reference software, test bit stream, digital rights management. To make the various parts of the standard compatible, this is undoubtedly a very difficult task and, therefore, delay the standards process.
2. Solely on the MPEG-4 video (that lS014496-2MPEG-4 second part of the image) is concerned, it is also a very complex standard, so far, it also involves a number of commercial on how the problem.
3. Since the standard is very complex, it has many categories, including a considerable number of parts are unable to obtain commercial applications.
4. Standard in many parts of the compromise deal made in technology, such as sentence structure is not as clear as it should have, which cause is difficult to enforce, and there are interoperability problems.
5. There are some elements of the standard is not very clear, it is not open enough.
6. Standard, there are still some errors, such as the reference standard and the required software, under the bit stream between, there is sometimes inconsistency.
MPEG-4 in the development and standardization of the process, the compression technology continues to develop -H.264/VC undoubtedly has better compression performance. In commercial applications, an important aspect of which is licensing issues: the second part of MPEG-4, the complete license management needs too long to process. Having said that, although there are many people interested in the second part of MPEG-4, but there are more new jobs are turning to H.264/AVC, VC-1 also included.
What is driving the H.264/AVC and VC-l standard set up? H. 264/AVC is very attractive, because there are several reasons:
1. H. 264/AVC is currently able to apply the best compression method (also the latest compression method);
2. It is in line with international standards and ITU support by MPEG/lS0
3.H. 264/AVC is concentrated in the video section, therefore, its standardization is relatively easy, but also can be achieved in a relatively short period of time (it does not require the same standards and interoperability in many other parts of the problem);
4. On H. 264/AVC standard itself, it noted that its use of the system elements of the general problem – for example, only need to make some modifications, you can use MPEG-2 transport stream to transmit H. 264/AVC Video and MPEG-2 video.
As mentioned above, is used for MPEG-2 Transport Stream (TS) for the entire television broadcasting industry, H. 264/AVC is more attractive. Able to H. 264/AVC video embedded in the MPEG-2 transport stream, which indicates that it is backward compatible, be able to use already existing, large, cast
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