mpeg1技术基础：iso/iec 11172-1 官方文档解析

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"iso/iec 11172-1" 是一份关于 MPEG-1 标准的系统部分的官方文档，由国际标准化组织 ISO 和国际电工委员会 IEC 制定。这份文档对于理解 MPEG-1 的音视频编码技术至关重要，特别是对那些涉及 MPEG-1 技术的开发者和工程师来说是必备的参考资料。 MPEG-1（Moving Picture Experts Group 第 1 代）是一种数字音频和视频压缩标准，最初设计用于在大约 1.5 Mbit/s 的数据速率下在数字存储媒体上编码运动图像和关联音频。该标准在 1990 年代初期发布，旨在适应低带宽的 CD-ROM 和早期的网络环境。文档的主要内容分为几个部分： 1. 前言和介绍：这部分提供了标准的基本背景信息，包括标准的目的和应用范围。 2. 多路复用操作（Pack Layer）：这部分详细描述了如何将多个音频和视频流组合成一个单一的传输流，以便于在有限的带宽下高效传输。 3. 单个流操作（Packet Layer）：涵盖了解复用过程，即如何从传输流中分离出各个独立的音频和视频流。同时讨论了同步问题，确保数据正确无误地恢复，并且与压缩层的关系也在此处解释。 4. 系统参考解码器：定义了一个理想的解码器模型，它能够正确处理并解码按照 MPEG-1 标准编码的流。 5. 一般规范元素：这部分规定了标准的适用范围以及引用的相关标准和文档。 6. 技术规范元素：包含了一系列定义、符号和缩写，以及与比特流语法描述方法、解码器需求等相关技术细节。这些定义包括算术、逻辑、关系、位操作符、赋值等运算，以及字段语义的规范和多路复用流的限制。 7. 编码结构和参数：描述了 MPEG-1 编码的基本结构，如帧率、分辨率、比特率等关键参数。 8. 系统目标解码器：定义了解码器应具备的功能，以确保正确解码和播放 MPEG-1 流。 9. 系统流语法的规范：详细阐述了比特流的语法结构，帮助开发者理解如何解析和构建有效的 MPEG-1 数据包。 10. 字段语义定义：解释了比特流中各个字段的具体含义，有助于理解数据的含义和作用。 11. 对多路复用流的限制：设定了关于如何构建和传输符合标准的多路复用流的一系列规则，以保证互操作性和兼容性。 "iso/iec 11172-1" 提供了 MPEG-1 标准的系统层面的全面指南，涵盖了从编码到解码的整个过程，以及相关算法和技术规范，对于开发、实现或分析 MPEG-1 编码的多媒体系统具有极高的参考价值。

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decoding time-stamp; DTS: A field that may be present in a packet header that indicates the time that an

access unit is decoded in the system target decoder.

Dequantization [Audio]: Decoding of coded subband samples in order to recover the original quantized

values.

dequantization: The process of rescaling the quantized DCT coefficients after their representation in the

bitstream has been decoded and before they are presented to the inverse DCT.

digital storage media; DSM: A digital storage or transmission device or system.

discrete cosine transform; DCT: Either the forward discrete cosine transform or the inverse discrete

cosine transform. The DCT is an invertible, discrete orthogonal transformation. The inverse DCT is

defined in 2-Annex A of Part 2.

display order: The order in which the decoded pictures should be displayed. Normally this is the same

order in which they were presented at the input of the encoder.

editing: The process by which one or more compressed bitstreams are manipulated to produce a new

compressed bitstream. Conforming editted bitstreams must meet the requirements defined in this

International Standard.

elementary stream: A generic term for one of the coded video, coded audio or other coded bit streams.

encoder: An embodiment of an encoding process.

encoding process: A process, not specified in this International Standard, that reads a stream of input

pictures or audio samples and produces a valid coded bitstream as defined in this International

Standard.

Entropy coding: Variable length noiseless coding of the digital representation of a signal to reduce

redundancy.

fast forward: The process of displaying a sequence, or parts of a sequence, of pictures in display-order

faster than real-time.

FFT: Fast Fourier Transformation. A fast algorithm for performing a discrete Fourier transform (an

orthogonal transform).

Filterbank [audio]: A set of band-pass filters covering the entire audio frequency range.

Fixed segmentation: A subdivision of the digital representation of an audio signal in to fixed segments

of time.

forbidden: The term 'forbidden" when used in the clauses defining the coded bitstream indicates that

the value shall never be used. This is usually to avoid emulation of start codes.

forced updating: The process by which macroblocks are intra-coded from time-to-time to ensure that

mismatch errors between the inverse DCT processes in encoders and decoders cannot build up

excessively.

forward motion vector: A motion vector that is used for motion compensation from a reference picture

at an earlier time in display order.

Frame [audio]: A part of the audio signal that corresponds to a fixed number of audio PCM samples.

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future reference picture: The future reference picture is the reference picture that occurs at a later time

than the current picture in display order.

Granules [Layer II]: 96 subband samples, 3 consecutive subband samples for all 32 subbands that are

considered together before quantisation

Granules [Layer III]: 576 frequency lines that carry their own side information.

group of pictures: A series of one or more pictures intended to assist random access. The group of

pictures is one of the layers in the coding syntax defined in Part 2 of this International Standard.

Hann window: A time function applied sample-by-sample to a block of audio samples before Fourier

transformation.

Huffman coding: A specific method for entropy coding.

Hybrid filterbank [audio]: A serial combination of subband filterbank and MDCT.

IMDCT: Inverse Modified Discrete Cosine Transform.

Intensity stereo: A method of exploiting stereo irrelevance or redundancy in stereophonic audio

programmes based on retaining at high frequencies only the energy envelope of the right and left

channels.

interlace: The property of conventional television pictures where alternating lines of the picture

represent different instances in time.

intra coding: Compression coding of a block or picture that uses information only from that block or

picture.

intra-coded picture; I-picture: A picture coded using information only from itself.

ISO 11172 (multiplexed) stream: A bitstream composed of zero or more elementary streams combined

in the manner defined in Part 1 of this International Standard.

Joint stereo coding: Any method that exploits stereophonic irrelevance or stereophonic redundancy.

Joint stereo mode: A mode of the audio coding algorithm using joint stereo coding.

layer [audio]: One of the levels in the coding hierarchy of the audio system defined in this International

Standard.

layer [video and systems]: One of the levels in the data hierarchy of the video and system

specifications defined in Parts 1 and 2 of this International Standard.

luminance (component): A matrix, block or sample of pels representing a monochrome representation of

the signal and related to the primary colours in the manner defined in CCIR Rec 601. The symbol used

for luminance is Y.

macroblock: The four 8 by 8 blocks of luminance data and the two corresponding 8 by 8 blocks of

chrominance data coming from a 16 by 16 section of the luminance component of the picture.

Macroblock is sometimes used to refer to the pel data and sometimes to the coded representation of the

pel and other data elements defined in the macroblock layer of the syntax defined in Part 2 of this

International Standard. The usage is clear from the context.

Mapping [audio]: Conversion of an audio signal from time to frequency domain by subband filtering

and/or by MDCT.

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Masking threshold [audio]: A function in frequency and time below which an audio signal cannot be

perceived by the human auditory system.

Masking: property of the human auditory system by which an audio signal cannot be perceived in the

presence of another audio signal .

MDCT: Modified Discrete Cosine Transform.

motion compensation: The use of motion vectors to improve the efficiency of the prediction of pel

values. The prediction uses motion vectors to provide offsets into the past and/or future reference

frames containing previously decoded pels that are used to form the prediction.

motion vector estimation: The process of estimating motion vectors during the encoding process.

motion vector: A two-dimensional vector used for motion compensation that provides an offset from

the coordinate position in the current picture to the coordinates in a reference picture.

MS stereo: A method of exploiting stereo irrelevance or redundancy in stereophonic audio programmes

based on coding the sum and difference signal instead of the left and right channels.

non-intra coding: Coding of a block or picture that uses information both from itself and from blocks

and pictures occurring at other times.

Non-tonal component: A noise-like component of an audio signal.

Nyquist sampling: Sampling at or above twice the maximum bandwidth of a signal.

pack: A pack consists of a pack header followed by one or more packets. It is a layer in the system

coding syntax described in Part 1 of this standard.

packet data: Contiguous bytes of data from an elementary stream present in a packet.

packet header: The data structure used to convey information about the elementary stream data

contained in the packet data.

packet: A packet consists of a header followed by a number of contiguous bytes from an elementary

data stream. It is a layer in the system coding syntax described in Part 1 of this International Standard.

Padding: A method to adjust the average length of an audio frame in time to the duration of the

corresponding PCM samples, by conditionally adding a slot to the audio frame.

past reference picture: The past reference picture is the reference picture that occurs at an earlier time

than the current picture in display order.

pel aspect ratio: The ratio of the nominal vertical height of pel on the display to its nominal horizontal

width.

pel: An 8-bit sample of luminance or chrominance data.

picture period: The reciprocal of the picture rate.

picture rate: The nominal rate at which pictures should be output from the decoding process.

picture: Source or reconstructed image data. A picture consists of three rectangular matrices of 8-bit

numbers representing the luminance and two chrominance signals. The Picture layer is one of the

layers in the coding syntax defined in Part 2 of this International Standard. NOTE: the term "picture" is

always used in this standard in preference to the terms field or frame.

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mpeg1技术基础：iso/iec 11172-1 官方文档解析

ISO_IEC_11172-2 MPEG1标准

ISO_IEC_11172-1 System 标准

ISO 11172-1

ISO/IEC 11172-1：编码与存储的动态图像与音频系统（1.5Mbps）

ISO_IEC_11172_3_cn.rar_11172-3_IEC_ISO/IEC_ISO/IEC 11172_iso

ISO/IEC 11172-3 英文版

mp3标准ISO/IEC 11172-3

ISO/IEC 11172-3 标准英文版

MP3标准——ISO/IEC 11172-3 13818-3

iso/iec 11172-3

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