Universal Serial Bus Device Class Definition for Video Devices: MPEG2-TS Revision 10 August 1, 2003
USB Device Class Definition for Video Devices: MPEG2-TS Contributors Abdul R Ismail Akihiro Tanabe Anand Ganesh Andy Hodgson Anshuman Saxena Bertrand Lee Charng Lee David Goll Eric Luttmann Fernando Urbina Geert Knapen Hiro Kobayashi Jean-Michel Chardon Jeff Zhu Ken-ichiro Ayaki Mitsuo Niida Nobuo Kuchiki Olivier Lechenne Paul Thacker Remy Zimmermann Shinichi Hatae Steve Miller Tachio Ono Yoichi Hirata Intel Corp Canon Inc Microsoft Corp STMicroelectronics Texas Instruments Microsoft Corp Sunplus Technology Co, Ltd Microsoft Corp Cypress Semiconductor Corp Apple Computer Inc Philips Electronics Microsoft Corp Logitech Inc Microsoft Corp Fujifilm Canon Inc Sanyo Electric Co, Ltd Logitech Inc STMicroelectronics Logitech Inc Canon Inc STMicroelectronics Canon Inc Matsushita Electric Industrial Co, Ltd Revision 10 August 1, 2003 ii
USB Device Class Definition for Video Devices: MPEG2-TS Copyright 2001, 2002, 2003 USB Implementers Forum All rights reserved TELLECTUAL PROPERTY DISCLAIMER THIS SPECIFICATION IS PROVIDED AS IS WITH NO WARRANTIES WHATSOEVER CLUDG ANY WARRANTY OF MERCHANTABILITY, FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY OTHERWISE ARISG OF ANY PROPOSAL, SPECIFICATION, OR SAMPLE A LICENSE IS HEREBY GRANTED TO REPRODUCE AND DISTRIBUTE THIS SPECIFICATION FOR TERNAL USE ONLY NO OTHER LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY OTHER TELLECTUAL PROPERTY RIGHTS IS GRANTED OR TENDED HEREBY AUTHORS OF THIS SPECIFICATION DISCLAIM ALL LIABILITY, CLUDG LIABILITY FOR FRGEMENT OF PROPRIETARY RIGHTS, RELATG TO IMPLEMENTATION OF FORMATION THIS SPECIFICATION AUTHORS OF THIS SPECIFICATION ALSO DO NOT WARRANT OR REPRESENT THAT SUCH IMPLEMENTATION(S) WILL NOT FRGE SUCH RIGHTS All product names are trademarks, registered trademarks, or service marks of their respective owners Revision 10 August 1, 2003 iii
USB Device Class Definition for Video Devices: MPEG2-TS Table of Contents 1 Introduction 1 11 Purpose 1 12 Scope 1 13 Related Documents1 14 Terms and Abbreviations 1 2 Video Class-Specific Information 2 21 Compression Class 2 22 Stream 2 3 -Specific Information4 31 Descriptors 4 311 MPEG-2 TS Format Descriptor 4 32 Video Samples 4 33 RTP Protocol Compatibility 4 4 Examples 5 41 Isochronous Transfer 5 42 Isochronous Transfer 6 43 Bulk Transfer 7 44 Bulk Transfer 8 Revision 10 August 1, 2003 iv
USB Device Class Definition for Video Devices: MPEG2-TS List of Tables Table 2-1 Definition for MPEG2-TS Format 2 Table 3-1 MPEG2-TS Format Descriptor 4 Revision 10 August 1, 2003 v
USB Device Class Definition for Video Devices: MPEG2-TS List of Figures Figure 4-1 Example MPEG2-TS Isochronous Transfer, Endpoint 5 Figure 4-2 Example MPEG2-TS Isochronous Transfer, Endpoint 6 Figure 4-3 Example MPEG2-TS Bulk Transfer, Endpoint 7 Figure 4-4 Example MPEG2-TS Bulk Transfer, Endpoint 8 Revision 10 August 1, 2003 vi
USB Device Class Definition for Video Devices: MPEG2-TS 1 Introduction 11 Purpose This document defines the MPEG2-TS (Transport Stream) payload format for devices that are compliant with the USB Device Class Definition for Video Devices document 12 Scope The payload format and associated header information is fully specified by this document This includes: - USB Video Class stream header - -specific header - format - RTP protocol compatibility 13 Related Documents USB Specification Revision 20, April 27, 2000, wwwusborg USB Device Class Definition for Video Devices, wwwusborg MPEG2TS Packets definitions shall comply with ISO/IEC 13818 series ISO/IEC 13818-1: Information technology -- Generic coding of moving pictures and associated audio information: Part 1: Systems ISO/IEC 13818-2: Information technology - Generic coding of moving pictures and associated audio information: Part 2: Video ISO/IEC 13818-3: Information technology - Generic coding of moving picture and associated audio information: Part 3: Audio ISO/IEC 13818-9: Information technology - Generic coding of moving pictures and associated audio information: Part 9: Extension for real time interface for systems decoders Pr ETS 300 468, Digital broadcasting systems for television, sound and data services Specification for service information (SI) in digital video broadcasting (DVB) systems 14 Terms and Abbreviations This section defines terms and abbreviations used throughout this document ADU UVC DVB SI ETS MPEG RTI TS TSP Term Description Application data unit USB Video Class Digital video broadcasting (in Europe) Service information European telecommunication standard Motion picture expert group Real time interface Transport stream Transport stream packet Revision 10 August 1, 2003 1
USB Device Class Definition for Video Devices: MPEG2-TS 2 Video Class-Specific Information 21 Compression Class The ISO/IEC JTC1/SC29 WG11 (also referred to as the MPEG committee) has defined the MPEG2 standard (ISO/IEC 13818); this document describes a packetization scheme to transport MPEG2-TS streams over error prone mediums The present specification adapts and describes this packetization for the USB Extensive use of the ISO/IEC standards terminology is used throughout this specification; the reader should consult the original references listed in section 13, "Related Documents", for the definitions of these terms Every USB payload transfer consists of the header block followed by a source data block The header block definition of the MPEG2TS payload format is described in section 22, "Stream " Based on the MPEG2-TS packet size, the length of the source data block is an integral multiple of 188 bytes The streaming data from multiple small TS packets are integrated into a single USB Video Class payload transfer The number of transport packets that are contained in a payload transfer is calculated based on the MPEG2-TS format descriptor s bpacketlength and bstridelength fields 22 Stream This section describes the stream header used for the MPEG2-TS payload format USB Video Class header definition for MPEG2-TS format Table 2-1 Definition for MPEG2-TS Format HLE Length BFH [0] EOH ERR STI RES SCR PTS EOF FID BFH[0]: Bit Field o FID: Frame ID o EOF: End of Frame o PTS: Presentation Time Stamp o SCR: Source Clock Reference o RES: Reserved o STI: Still Image o ERR: Error Bit o EOH: End of Revision 10 August 1, 2003 2
USB Device Class Definition for Video Devices: MPEG2-TS Length: Size: 1 [Byte] Value: 2 [Bytes] The header length value in MPEG2-TS class is fixed to 2 Bytes FID: Frame ID This tern has no meaning in MPEG2-TS format It shall be always set to zero EOF: End of Frame This term has no meaning in MPEG2-TS format It shall be always set to zero PTS: Presentation Time Stamp This term has no meaning in MPEG2-TS format It shall be always set to zero SCR: Source Clock Reference This term has no meaning in MPEG2-TS format It shall be always set to zero Revision 10 August 1, 2003 3
USB Device Class Definition for Video Devices: MPEG2-TS 3 -Specific Information 31 Descriptors 311 MPEG-2 TS Format Descriptor The MPEG2-TS Format Descriptor defines the characteristics of a specific MPEG2-TS stream A Terminal corresponding to a USB or endpoint, and the interface it belongs to, supports one or more format definitions MPEG2-TS format streams do not need to support the Presentation Time Stamp field in the stream header, as this information is already included in the transport stream MPEG2-TS Format Descriptors have no accompanying Frame Descriptors A MPEG2-TS Format Descriptor identifies the following, Table 3-1 MPEG2-TS Format Descriptor Offset Field Size Value Description 0 blength 1 Number Size of this Descriptor, in bytes: 7 1 bdescriptortype 1 Constant CS_TERFACE Descriptor type 2 bdescriptorsubtype 1 Constant VS_FORMAT_MPEG2TS Descriptor subtype 3 bformatindex 1 Number Index of this Format Descriptor 4 boffset 1 Number Offset to TSP packet within MPEG2 transport stride, in bytes If the stream contains only TSP packets, this field will be set to 0 5 bpacketlength 1 Number Length of TSP packet, in bytes 6 bstridelength 1 Number Length of MPEG2 transport stride If the stream contains only TSP packets, this will be equal to bpacketlength 32 Video Samples The scope of this specification is based on the ISO/IEC 13818 series Video sample information, such as aspect ration, picture position, quantization of audio sampling, number of audio channels, and so on, are described as a profile in the ISO/IEC 13818 series Therefore, this information is not included in this MPEG2-TS format specification 33 RTP Protocol Compatibility Please refer to the "RFC 2250 RTP Format for MPEG1/MPEG2 Video" (note that RFC 2250 is based on ISO/IEC 13818) Each specified source data block of this MPEG2-TS streaming format specification is equal to ISO/IEC 13818 as defined It means that there is no difference between an RFC2250 source data block, and a MPEG2-TS data block Therefore, it may remove only MPEG2-TS format in USB Video Class header block to convert from USB VC to RFC 3189 Revision 10 August 1, 2003 4
USB Device Class Definition for Video Devices: MPEG2-TS 4 Examples 41 Isochronous Transfer The following example shows the relationship between Transfers, the token and data packets when receiving isochronous transfers from the device This example shows high-speed, high-bandwidth transfers, but this is only illustrative and not a requirement of the MPEG2-TS payload format The actual bandwidth usage will vary according to the requirements of the device The base transmission rate (one TSP(188Bytes)/payload) in MPEG2-TS is 12032 Mbps SOF Packet DATA2 DATA1 DATA0 SOF Packet DATA2 DATA1 DATA0 Video Sample SOF Packet DATA1 DATA0 Figure 4-1 Example MPEG2-TS Isochronous Transfer, Endpoint Revision 10 August 1, 2003 5
USB Device Class Definition for Video Devices: MPEG2-TS 42 Isochronous Transfer The following example shows the relationship between Transfers, the token and data packets when sending isochronous transfers to the device This example shows high-speed, highbandwidth transfers, but this is only illustrative and not a requirement of the MPEG2-TS payload format The actual bandwidth usage will vary according to the requirements of the device SOF Packet MDATA MDATA DATA2 SOF Packet MDATA MDATA DATA2 Video Sample SOF Packet MDATA DATA1 Figure 4-2 Example MPEG2-TS Isochronous Transfer, Endpoint Revision 10 August 1, 2003 6
USB Device Class Definition for Video Devices: MPEG2-TS 43 Bulk Transfer The following example shows the relationship between Transfers, the token and data packets of the MPEG2-TS payload format when receiving bulk transfers from a device Handshake packets are not shown for the sake of clarity DATA0 DATA1 DATA0/1 DATA0 DATA1 DATA0/1 Video Sample DATA0 DATA1 Figure 4-3 Example MPEG2-TS Bulk Transfer, Endpoint Revision 10 August 1, 2003 7
USB Device Class Definition for Video Devices: MPEG2-TS 44 Bulk Transfer The following example shows the relationship between Transfers, the token and data packets of the MPEG2-TS payload format when sending bulk transfers to the device Handshake packets are not shown for the sake of clarity DATA0 DATA1 DATA0/1 DATA0 DATA1 DATA0/1 DATA0 DATA1 Figure 4-4 Example MPEG2-TS Bulk Transfer, Endpoint Revision 10 August 1, 2003 8