The QCP File Format and Associated Media Types R. Gellens Expires: November 2003 H. Garudadri Qualcomm 29 May 2003 The QCP File Format and Associated Media Types draft-gellens-qcp-01.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at The list of Internet-Draft Shadow Directories can be accessed at . Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract RFC 2658 specifies the streaming format for QCELP 13K vocoder data, but does not specify a storage format. Many implementations have been using the QCP file format for exchanging QCELP 13K data as well as EVRC and SMV data. (For example, Eudora, QuickTime(r), and cmda2000 handsets). Gellens [Page 1] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 This document specifies the QCP file format and updates the audio/qcelp media registration to specify this format for storage; and registers the audio/evrc-qcp and audio/smv-qcp media types for EVRC and SMV (respectively) data stored in this format. Gellens [Page 2] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 1. Conventions Used in this Document . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 3. QCP FILE FORMAT . . . . . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . 10 4.1. Update of Media Type Audio/qcelp . . . . . . . . . . . . 11 4.2. Update of Media Type Audio/vnd.qcelp . . . . . . . . . . 11 4.3. Registration of Audio/EVRC-QCP . . . . . . . . . . . . . 11 4.4. Registration of Audio/SMV-QCP . . . . . . . . . . . . . 12 5. Security Considerations . . . . . . . . . . . . . . . . . . . 13 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 7. Normative References . . . . . . . . . . . . . . . . . . . . 13 8. Informative References . . . . . . . . . . . . . . . . . . . 14 9. Editors' Addresses . . . . . . . . . . . . . . . . . . . . . 14 Intellectual Property Statement . . . . . . . . . . . . . . . 14 Full Copyright Statement . . . . . . . . . . . . . . . . . . . 15 1. Conventions Used in this Document The key words "REQUIRED", "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in this document are to be interpreted as described in "Key words for use in RFCs to Indicate Requirement Levels" [KEYWORDS]. 2. Introduction This document specifies the QCP format for storage of [QCELP] 13K, [EVRC], and [SMV] vocoder frames in files which may reside on network elements (e.g., media servers, Mulimedia Messaging System (MMS) centers, etc.) and third-generation cellular (3G) handsets, or be transmitted via email or other mechanisms. Vocoder frames read from a QCP file may be streamed using protocols and formats outside the scope of this document, delivered to an [EVRC], [SMV], or [QCELP] 13K decoder, or otherwise processed. The QCP format supports [QCELP] 13K as well as [EVRC] and [SMV] data. Note that this format is different from the EVRC and SMV storage format specified in [EVRC-SMV]. Gellens [Page 3] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 3. QCP FILE FORMAT The following describes the QCP file format using [ABNF]. A qcp file contains data frames generated by the [QCELP], [EVRC], or [SMV] vocoders. qcp-file = riff-qlcm fmt vrat [labl] [offs] data [cnfg] [text] riff-qlcm = RIFF riff-size QLCM fmt = FMT chunk-size major minor codec-info ; major and minor are set to the version of ; the QCP file format used to generate the ; file - currently, the following versions ; are defined: ; ; major = 2, minor = 0 ; used for SMV. ; major = 1, minor = 0 ; used for QCELP-13K and EVRC vrat = VRAT chunk-size var-rate-flag size-in-packets labl = LABL chunk-size label offs = OFFS chunk-size step-size num-offsets *offset ; number of repetitions of offset must equal ; num-offsets data = DATA chunk-size *packet [pad] ; repetitions of packet contain the actual ; packet data -- there should be as many ; packets as indicated by the size-in-packets ; element found elsewhere in this file format cnfg = CNFG chunk-size config text = TEXT chunk-size string [pad] ; string contains any information defined ; by the application riff-size = UINT32 ; riff-size should equal total size of file ; in bytes, excluding the size of RIFF and ; riff-size chunk-size = UINT32 Gellens [Page 4] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 ; chunk-size should equal the total size of ; the chunk described by the rule containing ; chunk-size, excluding the size of ; chunk-size itself and any elements that ; come before it in the rule, as well as ; the pad element, if present major = OCTET ; major version number of QCP format -- ; currently set as "2" -- however, "1" should ; be used instead for QCELP-13K and EVRC, to ; maintain compatibility with older software ; platforms minor = OCTET ; minor version number: currently set to "0" codec-info = codec-guid codec-version codec-name average-bps packet-size block-size sampling-rate sample-size variable-rate 5*UINT32 ; this identifies the codec used to encode ; the speech in this file, and any parameters ; needed in order to decode the speech ; the five UINT32 elements are reserved for ; use in future versions of this format, ; should be set to zero for now, and readers ; should allow non-zero values when reading ; files in this format var-rate-flag = UINT32 ; if zero, sizes of packets in data chunk are ; fixed at the value indicated by the ; packet-size field, found elsewhere in this ; file format ; if var-rate-flag is greater than zero but ; less than %xFFFF0000, packets are variable ; rate, and rate is determined by rate octet ; in each packet -- to determine the size of ; a packet, map the first octet (the rate ; octet) to the size of the rest of the ; packet, according to the rate-map ; information found elsewhere in this file ; values %xFFFF0001 and higher are reserved ; for use in future versions of this format Gellens [Page 5] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 size-in-packets = UINT32 ; this is the total number of packets in the ; data chunk in the file label = 48OCTET ; label is for generic storage for ; application use step-size = UINT32 ; difference in the times of sequential ; application stored in this chunk, in ; 100ms increments (step-size of 10 means ; 1 second) ; currently only a step-size of "10" is ; guaranteed to be supported by software ; capable of reading this file format num-offsets = UINT32 ; number of offsets in offs chunk -- must ; equal number of repetitions of offset ; element offset = UINT32 ; absolute octet offset in this QCP file ; where the beginning of the packet that is ; at a time index one step past the last ; offset is located -- step size is given ; in step-size packet = [rate-octet] (1*OCTET) ; the rate-octet element is present only if ; the var-rate-flag found elsewhere in the file ; indicates that the file contains ; variable-rate packets - if it is present, the ; octet is used to determine the size of the ; remainder of the packet (the number of octets ; which follow the rate-octet) ; No rate-octet is present if the var-rate-flag ; is set to zero, indicating a fixed size ; packet file - in this case, the number of ; octets in packet is equal to the value set ; in packet-size, found elsewhere in this ; file format ; It should be noted that there is always a ; codec rate octet in a packet, even if the ; var-rate-flag is zero, indicating fixed size Gellens [Page 6] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 ; packet files - in this case, although there ; is no rate-octet element in this syntax, the ; first octet in the packet is still considered ; the "rate" for the packet. ; Two examples follow to illustrate this. ; Example 1. Variable-rate QCELP ; var-rate-flag = %d1 ; variable-rate = %d5 %d34 %d4 %d16 %d3 %d7 %d2 ; %d3 %d1 %d0 %d0 ; packet = %d4 (34OCTET) ; packet = %d4 (34OCTET) ; packet = %d3 (16OCTET) ; packet = %d1 (3OCTET) ; Example 2. Fixed-rate, full-rate QCELP ; var-rate-flag = %d0 ; packet-size = %d35 ; packet = (35OCTET) ; first octet is %d4 ; packet = (35OCTET) ; first octet is %d4 ; packet = (35OCTET) ; first octet is %d4 ; packet = (35OCTET) ; first octet is %d4 pad = %x00 ; pad is present only if the number of bytes in ; the chunk described by the rule containing ; pad would otherwise be odd - if present, its ; size should NOT be included in the ; calculation for any chunk-size element also ; present in the chunk config = UINT16 ; config is a bitmapped configuration word, ; for application use string = *(%x01-FF) %x00 ; this is a zero-terminated string of octets -- ; although not limited to it, typically the ; string consists of us-ascii characters codec-guid = UINT32 UINT16 UINT16 8OCTET ; this is the unique identifier for the codec ; used to encode the packets in the data chunk ; The elements of this rule match the structure ; defined for a GUID in other specifications ; and formats. The first three elements are ; stored in little-endian octet order. Gellens [Page 7] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 ; When values for a GUID are expressed, the ; first three elements are expressed as a ; sequence of hexadecimal digits in normal ; network ordering (big-endian or most ; significant digit first) while the eight ; octet element is broken up into two groups, ; the first having four hexadecimal digits, ; and the second having twelve digits, all ; expressed in network ordering. ; For example, if the octets in a GUID as ; stored in a file are: ; %12 %34 %56 %78 %9A %BC %DE %F0 ; %0F %ED %CB %A9 %87 %65 %43 %21 ; then the GUID would have these values: ; UINT32 = %x78563412 ; UINT16 = %xBC9A ; UINT16 = %xF0DE ; 8OCTET = %x0F.ED.CB.A9.87.65.43.21 ; and the whole GUID would be expressed as: ; {78563412-BC9A-F0DE-0FED-CBA987654321} ; The following codec GUIDs are currently ; defined for QCP file format: ; ; QCELP-13K: ; {5E7F6D41-B115-11D0-BA91-00805FB4B97E} ; {5E7F6D42-B115-11D0-BA91-00805FB4B97E} ; EVRC: ; {E689D48D-9076-46B5-91EF-736A5100CEB4} ; SMV: ; {8D7C2B75-A797-ED49-985E-D53C8CC75F84} codec-version = UINT16 ; version number of codec used to encode the ; packets in the data chunk ; This value depends on the particular codec ; used to encode the packets. The following ; versions are currently defined: ; QCELP-13K: ; 1 or 2 ; EVRC, and SMV: ; 1 codec-name = 80OCTET Gellens [Page 8] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 ; the proper name of the codec, in us-ascii - ; unused octets after the name are set to zero average-bps = UINT16 ; average data rate, in bits per second, of ; the speech data represented in this file packet-size = UINT16 ; the size in octets of the largest possible ; packet in the data chunk block-size = UINT16 ; the number of samples encoded in every packet ; in the data chunk sampling-rate = UINT16 ; number of speech samples per second ; (typically 8000) sample-size = UINT16 ; number of bits per speech sample ; (typically 16) variable-rate = num-rates 8rate-map ; if num-rates is zero, and major version ; number of the QCP file is 2, then the ; rate-map elements are not used - instead, ; it is up to the decoder to determine the ; sizes of packets in the data chunk, even ; if var-rate-flag indicates the file uses ; variable rate packets ; otherwise, num-rates specifies how many ; different possible rate octets there are ; for the packets in the data chunk, and ; thus how many of the rate-map elements ; contain valid information num-rates = UINT32 ; this is the number of possible rate octets ; used in the packets in the data chunk rate-map = rate-size rate-octet ; this maps a possible rate octet for a packet ; to the size of the rest of the packet having ; that value for the rate octet rate-size = OCTET ; this is the size of a packet, excluding the Gellens [Page 9] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 ; rate octet rate-octet = OCTET ; this is the first octet of a packet in the ; data chunk, when the var-rate-flag set for ; the file indicates the file is variable rate UINT32 = 4OCTET ; this field contains a 32-bit integer stored ; as a sequence of four octets, in ; little-endian order (least significant ; octet first) UINT16 = 2OCTET ; this field contains a 16-bit integer stored ; as a sequence of two octets, in ; little-endian order (least significant ; octet first) OCTET = %x00-FF ; an octet, also called a byte - any possible ; combination of eight bits, forming a single ; integer or part of a larger integer having ; more than eight bits RIFF = %x52 %x49 %x46 %x46 QLCM = %x51 %x4C %x43 %x4D FMT = %x66 %x6D %x74 %x20 LABL = %x6C %x61 %x62 %x6C OFFS = %x6F %x66 %x66 %x73 DATA = %x64 %x61 %x74 %x61 CNFG = %x63 %x6E %x66 %x67 TEXT = %x74 %x65 %x78 %x74 Gellens [Page 10] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 4. IANA Considerations IANA is requested to update the audio/qcelp and audio/vnd.qcelp registrations and add the audio/evrc-qcp and audio/smv-qcp registrations as specified here. 4.1. Update of Media Type Audio/qcelp The audio/qcelp media registration should be updated to indicate that this specification is to be used for storage. 4.2. Update of Media Type Audio/vnd.qcelp The audio/vnd.qcelp media registration should be updated to indicate that use of this media type is deprecated, and note that the media type audio/qcelp should be used instead. 4.3. Registration of Audio/EVRC-QCP Media Type Name: audio Media Subtype Name: evrc-qcp Required Parameter: none Optional parameters: none Encoding considerations: The storage format specified in this document may be used with any transport mechanism. Security considerations: See Section 5 "Security Considerations" of this document. Public specification: this document Additional information: no Magic number: First four octets: RIFF Octets 9-12: QLCM (Note: octets 5-8 constitute the riff-size field, which is the size of the file minus the RIFF header. Since this could be anything, it isn't fixed and thus can't be used as part of the magic number.) File extensions: qcp, QCP Macintosh file type code: none Object identifier or OID: none Gellens [Page 11] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 Intended usage: COMMON. This file format is already in wide use in Internet email user agents, multimedia authoring and playing software, and cdma2000 handsets. Person & email address to contact for further information: Harinath Garudadri hgarudad@qualcomm.com Change controller: The IETF 4.4. Registration of Audio/SMV-QCP Media Type Name: audio Media Subtype Name: smv-qcp Required Parameter: none Optional parameters: none Encoding considerations: The storage format specified in this document may be used with any transport mechanism. Security considerations: See Section 5 "Security Considerations" of this document. Public specification: this document Additional information: no Magic number: First four octets: RIFF Octets 9-12: QLCM (Note: octets 5-8 constitute the riff-size field, which is the size of the file minus the RIFF header. Since this could be anything, it isn't fixed and thus can't be used as part of the magic number.) File extensions: qcp, QCP Macintosh file type code: none Object identifier or OID: none Gellens [Page 12] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 Intended usage: COMMON. This file format is already in wide use in Internet email user agents, multimedia authoring and playing software, and cdma2000 handsets. Person & email address to contact for further information: Harinath Garudadri hgarudad@qualcomm.com Change controller: The IETF 5. Security Considerations This document specifies a file format only, not a streaming protocol payload format nor a transfer method. As such, it introduces no security risks aside from those associated with any audio codec or media file format (for example, denial of service by transmitting a file larger than the receiver can handle). Note that those security concerns should be understood before using the file format specified here. 6. Acknowledgements Richard Walters created the ABNF notation for this specification and proof-read the text, among other helpful tasks. The qcp file format was originally developed by others within Qualcomm. The editor would like to thank Chuck Han and Livingstone Song for their contributions leading to this specification. 7. Normative References [ABNF] Crocker, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. [KEYWORDS] Bradner, "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [QCELP] 3GPP2 C.S0020 "High Rate Speech Service Option 17 for Wideband Spread Spectrum Communications Systems". Gellens [Page 13] Expires November 2003 Internet Draft The QCP File Format and Associated Media Types May 2003 [EVRC] 3GPP2 C.S0014 "Enhanced Variable Rate Codec, Speech Service Option 3 for Wideband Spread Spectrum Digital Systems ". (Used to be TIA/EIA/IS-127) [PureVoice] McKay, "RTP Payload Format for PureVoice(tm) Audio", RFC 2658, August 1999. [SMV] 3GPP2 C.S0030 "Selectable Mode Vocoder, Service Option for Wideband Spread Spectrum Communication Systems". 8. Informative References [EVRC-SMV] "RTP Payload Format for Enhanced Variable Rate Codecs (EVRC) and Selectable Mode Vocoders (SMV)", Li, draft-ietf-avt-evrc-smv-03.txt (approved for publication as an RFC). 9. Editors' Addresses Randall Gellens randy@qualcomm.com QUALCOMM Incorporated 5775 Morehouse Drive San Diego, CA 92121 USA Harinath Garudadri hgarudad@qualcomm.com QUALCOMM Incorporated 5775 Morehouse Drive San Diego, CA 92121 USA Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. 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