With HDTV and other resources, the emergence of high-definition, H.264 frequent the norm in front of us, HD-DVD and Blu-ray DVD plans are carried out using the standard programming. But since the second half of 2005, both the NVIDIA or ATI have to support H.264 hardware decode acceleration, as most boast about their own video technology. And the field of digital audio players have also brought us a wave of high-definition and H.264, digital audio players at home and abroad, many manufacturers have already begun to support such encoding video files, while the abundance of network resources has gradually enhanced. H.264 in the end is where the "sacred" mean? And traditions, such as RMVB encoder compared to what it advanced?
H.264, also part of MPEG-4 10th by ITU-T Video Coding Experts Group (VCEG) and ISO / IEC Moving Pictures Experts Group (MPEG) formed a joint video team of the joint (JVT, JointVideoTeam) proposed a high compression digital video codec standard. What is H.264? H.264 is a high-performance video codec technology. At present, the development of video codec technology, there are two organizations, one is "the ITU (ITU-T)", which developed the standards H.261, H.263, H.263 +, etc., and the other is " International Organization for Standardization (ISO) "It developed standards MPEG-1, MPEG-2, MPEG-4 and so on. And H.264 are the two organizations jointly established by the Joint Video Team (JVT) to develop a new digital video coding standard, so it is an ITU-T's H.264, it is ISO / IEC for MPEG-4 advanced video encoding (AdvancedVideoCoding, AVC), and it will be the MPEG-4 standard Part 10. Thus, MPEG-4AVC, MPEG-4Part10, or ISO/IEC14496-10, refer to H.264.
The biggest advantage of H.264 is a high data compression ratio, in the same conditions of image quality, H.264 is a compression ratio of MPEG-2 to 2 times higher than is MPEG-4 1.5 ~ 2 times. For example, if the size of the original documents for the 88GB, the use of MPEG-2 compression standard compressed into 3.5GB, for the 25:1 compression ratio, and the use of compression standard H.264 compressed into a 879MB, from 88GB to 879MB, H.264 compression ratio of 102:1 staggering! H.264 Why is there such a high compression ratio? Low bit rate (LowBitRate) played an important role, and MPEG-2 and MPEG-4ASP compared, such as compression technology, H.264 compression technology will go a long way to save the user's download time and data traffic charges. In particular, it is worth mentioning that, H.264 high compression ratio in the fluid also has high-quality images.
The advantages of H.264 algorithm
H.264 is a MPEG-4 technology based on the established, and its codec processes include five parts: frame and intra-prediction (Estimation), Transform (Transform) and inverse transform, quantization (Quantization) and anti-quantified loop filter (LoopFilter), entropy coding (EntropyCoding). H.264/MPEG-4AVC (H.264) in 1995 from MPEG-2 video compression standard issued after the latest and most promising video compression standard. H.264 is the ITU-T and ISO / IEC joint development team to develop the latest international video coding standard. The adoption of the standards under the same image quality of the compression efficiency standards than the previous 2 times more, so, H.264 is generally considered the most influential industry standards.
A, H.264 history of the development
H.264 in 1997, the ITU Video Coding Expert Group (VideoCodingExpertsGroup) when it was known as H.26L, in the ITU and ISO joint research was known as MPEG4Part10 (MPEG4AVC) or H.264 (JVT).
H.264, senior technical background
The main objective of the standard H.264 is: with other existing video coding standards, in the same bandwidth to provide better image quality.
And, H.264 and previous international standards such as H.263 and MPEG-4 compared to the advantages of the largest in the following four aspects:
1. Each video frame will be separated into components from the pixel block, the video frame encoding process of block-level can be achieved.
2. The use of redundant space method, some of the original video frame space prediction block, conversion, optimization and entropy coding (variable length coding).
3. Consecutive frames to block the use of temporary storage in different ways, so that only the frame of the continuous changes in the coding part. The algorithm uses motion compensation prediction and movement to complete. On certain blocks, in one or more have been frames encoded block the implementation of the search to determine the motion vectors, and thus behind the encoding and decoding blocks in the main forecast.
4. Redundancy using the remaining space on the video frame in the coding of residual block. For example: the source block and the corresponding projections of the different blocks, again using the conversion, optimization and entropy coding.
H.264 edge features and advanced
H.264 is the International Organization for Standardization (ISO) and the International Telecommunication Union (ITU) proposed the following common after the next-generation MPEG4 digital video compression format, that is, it retains the advantages of the past, compression technology and the best compression technology and other unmatched many advantages.
1. Low bit-stream (LowBitRate): and MPEG2 compression technology, such as MPEG4ASP and compared to the same image quality, the use of H.264 compression technology data of the MPEG2 is only 1 / 8, MPEG4 1 / 3.
Obviously, H.264 compression technology adoption will go a long way to save the user's download time and data traffic charges.
2. High-quality images: H.264 can provide continuous, smooth, high-quality images (DVD quality).
3. Fault-tolerant capability: H.264 offers a solution in an unstable network environment, such as error-prone packet loss of the necessary tools.
4. Adaptable network: H.264 adaptation layer provides a network (NetworkAdaptationLayer), the document makes H.264 can easily transfer in different networks (such as the Internet, CDMA, GPRS, WCDMA, CDMA2000, etc.).
Second, H.264 standards outlined
H.264 and previous standards, but also increases transform coding of DPCM hybrid coding mode. But it is a "return to basics" simplicity of design, do not have many options than H.263 + + much better compression performance; strengthened to adapt to a variety of channel capacity, the use of "network-friendly" structure and grammar is beneficial to the handling of error and packet loss; application of broad goals to meet the needs of different rates, different resolution and different transmission (storage) occasions demand.
Technically, it focused on the merits of the previous standards, and the absorption of the standard-setting experience. And H.263v2 (H.263 +) or MPEG-4 simple profile (SimpleProfile) compared to, H.264 encoding using methods similar to the above the best encoder, the bit rate, in most can save up to 50% of the rate. H.264 at all bit rate can continue to provide high video quality. H.264 to work in low-latency mode in order to adapt to real-time communication application (such as video conferencing), very good to work at the same time there is no delay in the application of restrictions, such as video storage and server-based video streaming applications . H.264 packet transmission network to provide packet loss to deal with the necessary tools, as well as error-prone wireless network tools to deal with bit error.
Level in the system, H.264 proposed a new concept in video coding layer (VideoCodingLayer, VCL) and network abstraction layer (NetworkAbstractionLayer, NAL) division between the conceptual, the former is the core of compressed video content statements , which is a specific type of network through the formulation of delivery, so the structure of the package to facilitate information and better information priority control.
Summary: H.264 = excellent + General
Many people dizzy terms, but sum up, very simple, H.264 is MPEG-4 standard, a project by virtue of its own superiority and versatility to become an internationally recognized standard.
