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GY/T 325-2019Technical requirements and measurement methods for AV-IT system in TV stations file-based producing and broadcasting networks (English PDF)

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Issued by

State Administration of Radio and Television

Level / Type

National · Recommended

Issue date

October 11, 2019

Implementation date

October 11, 2019

Scope

GY/T 325-2019 (Technical requirements and measurement methods for AV-IT system in TV stations file-based producing and broadcasting networks) is available as an English-translated PDF.

GY/T 325-2019 — This standard specifies the technical requirements and measurement methods for AV station's documented production and broadcasting network AV-IT system.

This standard applies to the R & D, production, acceptance, operation and maintenance of software and equipment in AV-IT systems.

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Document preview — GY/T 325-2019

National Standard of the People's Republic of China

Classification: M 61

Issued by: State Administration of Radio and Television

Foreword
1 Scope
2 Normative references
3 Terms, definitions and abbreviations
3.1 Terms and definitions
3.2 Acronyms
4 Program information exchange scenarios
4.1 Overview
4.2 Signal/File
4.3 File/Signal
4.4 File Streaming
4.5 Stream files
4.6 File/File
4.7 Flow signal
4.8 Signal Flow
4.9 Streams
5 Technical requirements
5.1 Input interface characteristics and data format
5.2 Output interface characteristics and data format
5.3 Encoding format
5.4 Package Format
5.5 Format conversion processing efficiency
5.6 File import processing efficiency
5.7 File Export Processing Efficiency
5.8 Composition/Packaging Processing Efficiency
5.9 Image Quality Evaluation
5.10 Video Channel Characteristics
5.11 Audio Channel Characteristics
5.12 Relative delay of audio and video
5.13 Channel Configuration
6 Measurement method
6.1 Input interface characteristics and data format
6.2 Output interface characteristics and data format
6.3 Encoding format
6.4 Package Format
6.5 Format conversion processing efficiency
6.6 File import processing efficiency
6.7 File Export Processing Efficiency
6.8 Composition/Packaging Processing Efficiency
6.9 Image Quality Evaluation
6.10 Video Channel Characteristics
6.11 Audio Channel Characteristics
6.12 Relative delay of audio and video
6.13 Channel Configuration
Appendix A (Normative Appendix) Format Conversion Processing Efficiency Test Materials
Appendix B (Normative Appendix) Composition/Packaging Processing Efficiency Test Materials
Appendix C (Normative Appendix) Image Quality Evaluation Materials
Appendix D (Normative Appendix) Video Channel Characteristics Test Materials
Appendix E (Normative Appendix) Audio Channel Characteristics Test Materials
Appendix F (Normative Appendix) Audio and Video Relative Delay Test Materials
Appendix G (Normative Appendix) Channel Configuration Check Material
References

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

Please note that some elements of this document may involve patents. The issuer of this document is not responsible for identifying these patents.

This standard is under the jurisdiction of the National Radio, Film and Television Standardization Technical Committee (SAC/TC 239).

This standard was drafted. China Central Radio and Television (CCTV), State Administration of Radio and Television Broadcasting and Television Planning Institute.

1 Scope

This standard specifies the technical requirements and measurement methods for AV station's documented production and broadcasting network AV-IT system.

This standard applies to the R & D, production, acceptance, operation and maintenance of software and equipment in AV-IT systems.

2 Normative references

The following documents are essential for the application of this document. For dated references, only the dated version applies to this document.

For undated references, the latest version (including all amendments) applies to this document.

GB/T 31001-2014 Test image for subjective evaluation of high definition television GY/T 134-1998 Digital TV image quality subjective evaluation method GY/T 157-2000 studio high-definition television digital video signal interface GY/T 158-2000 studio digital audio signal interface GY/T 170-2001 Cable Digital TV Broadcasting Channel Coding and Modulation Specification ETSI TS 102 034 V1.5.1 transmits DVB services based on MPEG-2 TS (Transport of MPEG-2 TS Based) over IP networks DVB Services over IP Based Networks)

3 Terms, definitions and abbreviations

3.1 Terms and definitions

The following terms and definitions apply to this document.

3.1.1

Processing efficiency the ratio of the length of the material to the time it takes to complete the AV-IT processing of the material, the unit is double speed.

3.2 Acronyms

The following abbreviations apply to this document.

AES/EBU Audio Engineering Society/European Broadcasting Union Union) ASI Asynchronous Serial Interface AVI Audio Video Interleaved DSCQS Double Stimulus Continuous Quality Scale HD-SDI High Definition-Serial Digital Interface MOV Movie Digital Video MPEG Moving Picture Experts Group MXF Material eXchange Format PCM Pulse Code Modulation PSNR Peak Signal to Noise Ratio TS Transport Stream UDP User Datagram Protocol

4 Program information exchange scenarios

4.1 Overview

In the production and broadcasting network system, video and audio programs appear in two forms. real-time and non-real-time. The main form of real-time morphology is real-time baseband Signal or real-time stream, the main manifestation of non-real-time form is static storage file or formatted static storage data.

In the production and broadcasting network system, different program forms or different forms of the same program form can be converted to each other. To achieve this conversion the technical system of the process is called the AV-IT system, which is generally responsible for performing transcoding and decoding of compressed video and audio, encoding of baseband video and audio, and media Format data encapsulation, decapsulation and up-down conversion, synthesis/packaging, etc.

The schematic diagram of the AV-IT system that realizes the mutual conversion between program information forms or forms is shown in Figure 1.

Encapsulation/Decapsulation Encapsulation Conversion interface Transcoding codec up and down Transform IT system AV-IT system up and down Transform Signal/Stream Processing Domain File processing domain AV system

Figure 1 Schematic of the AV-IT system that realizes the conversion of two kinds of program information

Program information processing in the form of real-time baseband signals can be completed in the signal processing domain, and program information processing in the form of real-time code streams can be performed at the stream.

It can be completed in the physical domain. Program information processing in the form of files can be completed in the file processing domain. At the same time, program information can be transferred to each other in three domains.

change. The conversion process of the program information in the signal/compressed code stream/file domain is shown in Figure 2.

File signal

Figure 2 Program information conversion between signal/compressed code stream/file domain

When the program information is converted between the three domains, in addition to the streaming, signal, and signal scenes, this standard specifies the information through the AV-IT system.

7 types of program information exchange. file, file, signal, file, stream, file, file, stream, signal Scenario measurement items and their technical requirements and measurement methods.

Note. "" is a program information form or program information form conversion symbol, which means that the program information is converted from the form or form on the left side of the conversion character to the right side of the conversion character.

4.2 Signal files

The program information processing sequence is. signal input, signal interface adaptation, up-down conversion (if included), encoding, packaging, file input Out, as shown in Figure 3.

File signal

Encapsulation

interface

coding

IT system

AV-IT system

up and down

Transform

Signal processing domain File processing domain AV system

Figure 3 Program information from signal to file

The measurement items, technical requirements and measurement methods of this process are shown in Table 1.

Table 1 Technical requirements and measurement methods of signal files

Serial number measurement item technical requirements chapter number

1 Input interface characteristics 5.1 6.1

2 Signal format (input) 5.1 6.1

3 Encoding format (output) 5.3 6.3

4 Package format (output) 5.4 6.4

5 File export processing efficiency 5.7 6.7

6 Image quality evaluation 5.9 6.9

7 Video channel characteristics 5.10 6.10

8 Audio channel characteristics 5.11 6.11

9 Relative delay of audio and video 5.12 6.12

10-channel configuration 5.13 6.13

4.3 File/Signal

The program information processing sequence is. file input, decapsulation, decoding, up-down conversion (if included), signal interface adaptation, signal Output, as shown in Figure 4.

File signal

Decapsulation

interface

decoding

IT system

AV-IT system

up and down

Transform

Signal processing domain File processing domain AV system

Figure 4 Program information from file to signal

The measurement items, technical requirements and measurement methods of this process are shown in Table 2.

Table 2 Technical requirements and measurement methods

Serial number measurement item technical requirements chapter number

1 Output interface characteristics 5.2 6.2

2 Signal format (output) 5.2 6.2

3 Encoding format (input) 5.3 6.3

4 Package format (input) 5.4 6.4

5 File import processing efficiency 5.6 6.6

6 Video channel characteristics 5.10 6.10

7 Audio channel characteristics 5.11 6.11

8 Audio and video relative delay 5.12 6.12 9-channel configuration 5.13 6.13

4.4 File Streaming

The program information processing sequence is. file input, decapsulation, decoding (if included), up-down conversion (if included), encoding (such as Including), encapsulation, stream interface adaptation, and compressed code stream output, as shown in Figure 5.

interface

up and down

Transform

IT system

AV-IT system

Stream processing domain File processing domain File signal AV system Decapsulation decoding coding Encapsulation

Figure 5 Program information from file to stream

The measurement items, technical requirements and measurement methods of this process are shown in Table 3.

Table 3 Technical requirements and measurement methods for document flow

Serial number measurement item technical requirements chapter number

1 Output interface characteristics 5.2 6.2

2 Encoding format (input) 5.3 6.3

3 Encoding format (output) 5.3 6.3

4 Package format (input) 5.4 6.4

5 Package Format (Stream Output) 5.4 6.4

6 File import processing efficiency 5.6 6.6

7 Image quality evaluation 5.9 6.9

8 Video channel characteristics 5.10 6.10

9 Audio channel characteristics 5.11 6.11

10 Relative delay of audio and video 5.12 6.12

11-channel configuration 5.13 6.13

4.5 Stream files

The program information processing sequence is. compressed stream input, stream interface adaptation, decapsulation, decoding (if included), up-down conversion (such as Including), encoding (if included), packaging, and file output, as shown in Figure 6.

interface

up and down

Transform

IT system

AV-IT system

Stream processing domain File processing domain File signal AV system Encapsulation coding decoding Decapsulation

Figure 6 Program information from stream to file

The measurement items, technical requirements and measurement methods of this process are shown in Table 4.

Table 4 Technical requirements and measurement methods for streaming documents

Serial number measurement item technical requirements chapter number

1 Input interface characteristics 5.1 6.1

2 Encoding format (input) 5.3 6.3

3 Encoding format (output) 5.3 6.3

4 Encapsulation Format (Stream Input) 5.4 6.4

5 Package format (output) 5.4 6.4

6 File export processing efficiency 5.7 6.7

7 Image quality evaluation 5.9 6.9

8 Video channel characteristics 5.10 6.10

9 Audio channel characteristics 5.11 6.11

10 Relative delay of audio and video 5.12 6.12 11-channel configuration 5.13 6.13

4.6 File/File

The program information processing sequence is. file input, decapsulation, decoding (if included), encoding (if included), packaging, file output Out, as shown in Figure 7.

interface

IT system

AV-IT system

Signal/Stream Processing Domain File A File Processing Domain File B File signal AV system Encapsulation encode decode Decapsulation

Figure 7 Program information from file to file

The measurement items, technical requirements and measurement methods of this process are shown in Table 5.

Table 5 Technical requirements and measurement methods of documents and documents

Serial number measurement item technical requirements chapter number

1 Encoding format (input) 5.3 6.3

2 Encoding format (output) 5.3 6.3

3 Package format (input) 5.4 6.4

4 Package format (output) 5.4 6.4

5 Format conversion processing efficiency 5.5 6.5

6 File import processing efficiency 5.6 6.6

7 File export processing efficiency 5.7 6.7

8 Synthesis/packet processing efficiency 5.8 6.8

9 Image quality evaluation 5.9 6.9

10 Video Channel Characteristics 5.10 6.10

11 Audio channel characteristics 5.11 6.11

12 Relative delay of audio and video 5.12 6.12

13-channel configuration 5.13 6.13

4.7 Flow signal

The program information processing sequence is. compression code stream input, stream interface adaptation, decapsulation, decoding, up-down conversion (if included), information no. interface adaptation, signal output, as shown in Figure 8.

File signal

interface

decoding

IT system

AV-IT Department

Up-down

Signal processing domain AV system Stream processing domain Decapsulation File domain

Figure 8 Program information from stream to signal

The measurement items, technical requirements and measurement methods of this process are shown in Table 6.

Table 6 Technical requirements and measurement methods for streaming signals

Serial number measurement item technical requirements chapter number

1 Input interface characteristics 5.1 6.1

2 Output interface characteristics 5.2 6.2

3 Signal format (output) 5.2 6.2

4 Encoding format (input) 5.3 6.3

5 Encapsulation Format (Stream Input) 5.4 6.4

6 Video channel characteristics 5.10 6.10

7 Audio channel characteristics 5.11 6.11

8 Audio and video relative delay 5.12 6.12 9-channel configuration 5.13 6.13

4.8 Signal Flow

The program information processing sequence is. signal input, signal interface adaptation, up-down conversion (if included), encoding, encapsulation, stream interface Adaptive, real-time stream output, as shown in Figure 9.

File signal

interface

coding

IT system

AV-IT system

Up-down

Signal processing domain AV system Stream processing domain Encapsulation File domain

Figure 9 Program information from signal to stream

The measurement items, technical requirements and measurement methods of this process are shown in Table 7.

Table 7 Technical requirements and measurement methods for signal flow

Serial number measurement item technical requirements chapter number

1 Input interface characteristics 5.1 6.1

2 Output interface characteristics 5.2 6.2

3 Signal format (input) 5.2 6.2

4 Encoding format (output) 5.3 6.3

5 Package Format (Stream Output) 5.4 6.4

6 Video channel characteristics 5.10 6.10

7 Audio channel characteristics 5.11 6.11

8 Audio and video relative delay 5.12 6.12 9-channel configuration 5.13 6.13

4.9 Stream

The program information processing sequence is. code stream input, stream interface adaptation, decapsulation, decoding (if included), encoding (if included), Encapsulation, stream interface adaptation, and real-time stream output, as shown in Figure 10.

file

signal

interface

coding

IT system

AV-IT system

Stream processing domain AV system Stream processing domain Encapsulation File domain decoding Decapsulation

Figure 10 Program information from stream to stream

5 Technical requirements

5.1 Input interface characteristics and data format the corresponding characteristics and data format requirements of the input interface are shown in Table 8.

Table 8 Input interface characteristics and data format

Serial Interface Type Technical Requirements

1 HD-SDI can receive signals and data according to GY/T 157-2000

2 ASI can receive signals and data according to GY/T 170-2001

3 TS over UDP can receive data in accordance with ETSI TS 102 034 V1.5.1

4 AES/EBU can receive data according to GY/T 158-2000

5.2 Output interface characteristics and data format the corresponding characteristics and data format requirements of the output interface are shown in Table 9.

Table 9 Output interface characteristics and data format

Serial Interface Type Technical Requirements

1 HD-SDI meets the requirements of GY/T 157-2000

2 ASI meets the requirements of GY/T 170-2001

3 TS over UDP meets the requirements of ETSI TS 102 034 V1.5.1

4 AES/EBU meets the requirements of GY/T 158-2000 5.3 encoding format the system under test shall be able to support the encoding format of Table 10 in the input link, and shall be able to generate one or more encoding grids in accordance with Table 10 in the output link.

formula.

Table 10 Encoding format

Serial number encoding format

1 AVC-Intra

2 DNxHD

3 ProRes 422

4 MPEG-2

5 Linear PCM

6 H.264 (optional)

7 H.265 (optional)

8 AVS (optional)

5.4 Package Format

The system under test should be able to decapsulate the format of Table 11 in the input link and generate one or more packaging grids in accordance with Table 11 in the output link.

formula.

Table 11 Package format

Serial number package format

1 MXF Op1a

2 MXF Op-Atom

3 AVI

4 TS

5 MOV

6 WAV

5.5 Format Conversion Processing Efficiency the test materials are shown in Appendix A. The format conversion processing efficiency should be no less than 2.1 times the speed.

5.6 File Import Processing Efficiency when importing files through the drive, the import efficiency should be no less than 2x.

5.7 File Export Processing Efficiency when exporting files through the drive, the export efficiency should be no less than 2 times faster.

5.8 Composition/Package Processing Efficiency the test materials are shown in Appendix B. The synthesis/packing processing efficiency should be no less than 4.2 times the speed.

5.9 Image Quality Evaluation the image quality evaluation may adopt a subjective evaluation method or a subjective evaluation objectification method, and a subjective evaluation method is preferred.

The image sequence is selected from GB/T 31001-2014, and the number of image sequences is >=4. The test materials are shown in Appendix C.

Subjective evaluation of image quality, using the DSCQS method specified in GY/T 134-1998, the number of evaluation personnel is >=15, and the evaluation results should >=75% of the image sequence relative to the source image sequence quality degradation percentage <=8%, the rest of the image sequence relative to the image of the source image sequence the percentage of quality reduction is <=12%.

When there are more than three image quality evaluations, a subjective evaluation method can be adopted. After calculating the image quality score, you should the lowest score is verified by subjective evaluation. If it meets the subjective evaluation requirements for image quality, all image quality is considered full Meet image quality requirements.

When there is no subjective evaluation condition, an objective method of subjective evaluation of image quality can be adopted, and the quality score of the measured image should reach "damage Injuries are perceptible but not obvious. "The indicators used for different objective evaluations are different. If PSNR is used, the score should not be lower than 34dB.

5.10 Video Channel Characteristics the video channel characteristics shall meet the requirements of Table 12.

Table 12 Video channel characteristics

Measurement item

Technical index

Y Cb Cr

1 intervention gain ± 0.1 ± 0.1 ± 0.1

2 Amplitude-frequency characteristics Frequency range 0 ~ 30MHz 0 ~ 15MHz 0 ~ 15MHz Amplitude tolerance ± 0.2dB ± 0.2dB ± 0.2dB

3 Non-linear distortion <=1.5% <=1.5% <=1.5%

5.11 Audio Channel Characteristics in addition to the low-frequency enhancement channel, the audio channel characteristics of other channels shall meet the requirements of Table 13.

Table 13 Audio channel characteristics

Technical index of measurement item

1 Total harmonic distortion

2 Amplitude frequency response (20Hz ~ 20kHz) -0.5dB ~ 0.5dB

3 Noise signal output level (unweighted) <=-93dBFS (16bit);

<=-117dBFS (20bit or 24bit) 4 channel level difference <=0.5dB 5 channel phase difference

5.12 Relative Delay of Audio and Video the relative delay of audio and video should be -20ms to 22.5ms. A positive value indicates that the sound is ahead of the image.

5.13 channel configuration the number and order of the output channels of the system under test should be consistent with the configuration requirements.

6 Measurement method

6.1 Input interface characteristics and data format

6.1.1 HD-SDI measurement

6.1.1.1 Measurement block diagram the measurement block diagram is shown in Figure 11.

System under test

HD-SDI

Video Tester Playout Server Test material output signal

Figure 11 HD-SDI input interface characteristics and data format measurement block diagram

6.1.1.2 Measurement procedure the measurement steps are as follows.

a) Connect the test system according to Figure 11, convert the materials in Appendix D into HD-SDI signals and input them to the system under test;

b) Configure the process parameters, set the output encoding format to MPEG-2, and optionally package it

c) implementation of processing;

d) Use a video tester to test the output signal of the system under test (if the output is a stream or a file, it needs to be collected and played back as an HD-SDI signal) Video channel characteristics and recording.

6.1.2 ASI

6.1.2.1 Measurement block diagram the measurement block diagram is shown in Figure 12.

System under test

ASI

Video tester

Broadcast server

Encoder

Test material output signal

Figure 12 ASI input interface characteristics and data format measurement block diagram

6.1.2.2 Measurement procedure the measurement steps are as follows.

a) Connect the test system according to Figure 12, convert the materials in Appendix D into ASI signals and input them into the system under test

b) Configure the process parameters, set the output encoding format to MPEG-2, and optionally package it

c) implementation of processing;

6.1.3 TS over UDP

6.1.3.1 Measurement block diagram the measurement block diagram is shown in Figure 13.

System under test

TS over UDP

Video tester

Playout server

Encoder

Test material output signal

Figure 13 TS over UDP input interface characteristics and data format measurement block diagram

6.1.3.2 Measurement procedure the measurement steps are as follows.

a) Connect the test system according to Figure 13, convert the material in Appendix D into TS over UDP media stream and input it to the system under test;

b) Configure the process parameters, set the output encoding format to MPEG-2, and optionally package it

c) implementation of processing;

6.1.4 AES/EBU

6.1.4.1 Measurement block diagram the measurement block diagram is shown in Figure 14.

System under test

AES

Video tester

Playout server

De-embedder

Output signal test material

Figure 14 AES/EBU input interface characteristics and data format measurement block diagram

6.1.4.2 Measurement procedure the measurement steps are as follows.

a) Con...

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 31 pages — is available in the English PDF.

Referenced standards

Normative references

GB/T 31001-2014Test materials to be used in subjective assessment for high definition television

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