31-08-2012, 03:23 PM
Overview, implementation and comparison of Audio Video Standard (AVS) China and H.264/MPEG -4 part 10
[attachment=33023]
Introduction
In real world applications compression is the most important part of the data transmission. Compression depends on the fact that the data is redundant in nature. It implies that up to some extent it was generated using some set of rules, and if those rules are known, the data can be accurately predicted. An encoder creates a compressed file that is ready for transmission or storage, retaining the information in the encoded data bits. Usually, video and audio files are large in nature so, compression becomes unavoidable in such conditions. The general block diagram explaining the scope of coding standardization is shown in Figure 1.
To play such a compressed file, an inverse algorithm is applied to produce a video that shows virtually the same content as the original source video. The time it takes to compress, send, decompress and display a file is called latency. The more advanced the compression algorithm, the higher the latency, given the same processing power. A pair of algorithms that works together is called a video codec (encoder/decoder). Video codecs that implement different standards are normally not compatible with each other; that is, video content that is compressed using one standard cannot be decompressed with a different standard. For instance, an MPEG-4 Part 2 decoder will not work with an H.264 encoder [2]. Different video compression standards use different methods to avoid data redundancy and therefore result in different bit rates, qualities and latency.
Encoder and decoder of AVS China
The AVS video coding standard is based on the classic hybrid DPCM-DCT coder which was first introduced by Jain and Jain in 1979 [24]. Temporal redundancy is removed by motion-compensated DPCM coding. Residual spatial redundancy is removed first by spatial prediction, and finally by transform coding. Statistical redundancy is removed by entropy coding.
Decoder
The decoder shown in Figure 4 accepts the constant rate signal from the storage or transmission and stores it temporarily in a rate buffer. The data is read out at a rate demanded by the decoding of each macroblock and picture. The signal is parsed to separate the quantization parameter, motion vectors and other side information from the coded data signal.
AVS video Jizhun profile
Jizhun profile is defined as the first profile in the national standards of AVS China-Part 2 [14], approved as national standard in 2006. This profile mainly focuses on digital video applications like commercial broadcasting and storage media, including high-definition applications. Basically it is preferred for high
coding efficiency on video sequences of higher resolutions, at the expense of moderate computational complexity.
AVS China Jiben profile
Jiben profile is defined in AVS-Part 7 [14] taking into account mainly mobility video applications with smaller picture resolution. Thus, computational complexity becomes a critical issue. Also the ability of error resilience is needed due to the wireless transporting environment. AVS-Part 7 reached to final committee draft at the end of 2004 [14].
AVS China Shenzhan profile
The profile AVS-Shenzhan focuses exclusively on standardizing the video surveillance applications. Especially, there are special features of sequences from video surveillance such as the random noise appearing in pictures, relatively lower encoding complexity affordable, and friendliness to events detection and searching required [14]. Hence corresponding techniques considering a proper process on these special features will be encouraged.
AVS China Jiaqiang profile
Jiaqiang profile is mainly focused to fulfill the needs of multimedia entertainment; one of the major concerns of this profile is movie compression for high-density storage [14]. Relatively higher computational complexity can be tolerated at the encoder side to provide higher video quality, with compatibility to AVS-Part 2 as well. Table 2 shows the summary of AVS China profiles.
[attachment=33023]
Introduction
In real world applications compression is the most important part of the data transmission. Compression depends on the fact that the data is redundant in nature. It implies that up to some extent it was generated using some set of rules, and if those rules are known, the data can be accurately predicted. An encoder creates a compressed file that is ready for transmission or storage, retaining the information in the encoded data bits. Usually, video and audio files are large in nature so, compression becomes unavoidable in such conditions. The general block diagram explaining the scope of coding standardization is shown in Figure 1.
To play such a compressed file, an inverse algorithm is applied to produce a video that shows virtually the same content as the original source video. The time it takes to compress, send, decompress and display a file is called latency. The more advanced the compression algorithm, the higher the latency, given the same processing power. A pair of algorithms that works together is called a video codec (encoder/decoder). Video codecs that implement different standards are normally not compatible with each other; that is, video content that is compressed using one standard cannot be decompressed with a different standard. For instance, an MPEG-4 Part 2 decoder will not work with an H.264 encoder [2]. Different video compression standards use different methods to avoid data redundancy and therefore result in different bit rates, qualities and latency.
Encoder and decoder of AVS China
The AVS video coding standard is based on the classic hybrid DPCM-DCT coder which was first introduced by Jain and Jain in 1979 [24]. Temporal redundancy is removed by motion-compensated DPCM coding. Residual spatial redundancy is removed first by spatial prediction, and finally by transform coding. Statistical redundancy is removed by entropy coding.
Decoder
The decoder shown in Figure 4 accepts the constant rate signal from the storage or transmission and stores it temporarily in a rate buffer. The data is read out at a rate demanded by the decoding of each macroblock and picture. The signal is parsed to separate the quantization parameter, motion vectors and other side information from the coded data signal.
AVS video Jizhun profile
Jizhun profile is defined as the first profile in the national standards of AVS China-Part 2 [14], approved as national standard in 2006. This profile mainly focuses on digital video applications like commercial broadcasting and storage media, including high-definition applications. Basically it is preferred for high
coding efficiency on video sequences of higher resolutions, at the expense of moderate computational complexity.
AVS China Jiben profile
Jiben profile is defined in AVS-Part 7 [14] taking into account mainly mobility video applications with smaller picture resolution. Thus, computational complexity becomes a critical issue. Also the ability of error resilience is needed due to the wireless transporting environment. AVS-Part 7 reached to final committee draft at the end of 2004 [14].
AVS China Shenzhan profile
The profile AVS-Shenzhan focuses exclusively on standardizing the video surveillance applications. Especially, there are special features of sequences from video surveillance such as the random noise appearing in pictures, relatively lower encoding complexity affordable, and friendliness to events detection and searching required [14]. Hence corresponding techniques considering a proper process on these special features will be encouraged.
AVS China Jiaqiang profile
Jiaqiang profile is mainly focused to fulfill the needs of multimedia entertainment; one of the major concerns of this profile is movie compression for high-density storage [14]. Relatively higher computational complexity can be tolerated at the encoder side to provide higher video quality, with compatibility to AVS-Part 2 as well. Table 2 shows the summary of AVS China profiles.