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@@ -14,7 +14,7 @@ alignment and other data. May take an "extended" form, with additional data
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the file or if it is a compressed format.
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.IP data
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The audio data itself. PCM audio data is always stored as interleaved samples.
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.SS Auxiliary WAV Chunks
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.SS Optional WAVE Chunks
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.IP JUNK
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A region of the file not currently in use. Clients sometimes add these before
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the
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@@ -39,32 +39,12 @@ four-character code identifying the form of the list, and is then followed
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by chunks of the standard key-length-data form, which may themselves be
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LISTs that themselves contain child chunks. WAVE files don't tend to have a
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very deep heirarchy of chunks, compared to AVI files.
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.SS Extensions for Large Files
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.IP RF64
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An RF64 file has affordances to hold chunks larger than four gigabytes.
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RF64 is designed so that a RIFF WAVE file can be in-place upgraded to an
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RF64 without having to rewrite any audio or metadata that may already be
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written. An RF64 file begins with an
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.I RF64 LIST
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form instead of a
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.I RIFF
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form. This is immediately followed by the obligatory...
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.IP ds64
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In RF64 files, the ds64 chunk begins the chunk list (in fact it must appear at
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a fixed offset) and provides a list of 64-bit chunk sizes for any chunks in the
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file that exceed four gigabytes. In an RF64 file, any chunk that exceeds the
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32 bit size restriction will set its length field (after the identifier) to
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.I 0xFFFFFFFF
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and will write its true size into the list in
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.IR ds64 .
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.SS RIFF Metadata
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The RIFF container format has a metadata system common to all RIFF files, WAVE
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being the most common at present, AVI being another very common format
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historically.
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.IP INFO
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A
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.I LIST
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form containing a flat list of chunks, each containing text metadata. The role
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.IP "LIST form INFO"
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A flat list of chunks, each containing text metadata. The role
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of the string, like "Artist", "Composer", "Comment", "Engineer" etc. are given
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by the four-character code: "Artist" is
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.IR IART ,
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@@ -77,10 +57,8 @@ Comment is
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etc.
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.IP cue
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A binary list of cues, which are timed points within the audio data.
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.IP adtl
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A
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.I LIST
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form containing text labels
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.IP "LIST form adtl"
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Contains text labels
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.RI ( labl )
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for the cues in the
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.I cue
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@@ -92,14 +70,14 @@ but hosts tend to use notes for longer text), and "length text"
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.I ltxt
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metadata records, which can give a cue a length, making it a range, and a text
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field that defines its own encoding.
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.IP cset
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.IP CSET
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Defines the character set for all text fields in
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.IR INFO ,
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.I adtl
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and other RIFF-defined text fields. By default, all of the text in RIFF
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metadata fields is Windows Latin 1/ISO 8859-1, though as time passes many
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clients have simply taken to sticking UTF-8 into these fields. The
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.I cset
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.I CSET
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cannot represent UTF-8 as a valid option for text encoding, it only speaks
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Windows codepages, and we've never seen one in a WAVE file in any event and
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it's vanishingly likely an audio app would recognize one if it saw it.
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@@ -136,14 +114,14 @@ and encoding properties of individual channels in the WAVE file, and if the
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WAVE file contains object-based audio, it will also give all of the positioning
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and panning automation envelopes.
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.IP bxml
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A gzip-compressed version of the
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This is defined by the ITU as a gzip-compressed version of the
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.I axml
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chunk.
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.IP sxml
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A hybrid binary/gzip-compressed-XML chunk that associates ADM
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This is a hybrid binary/gzip-compressed-XML chunk that associates ADM
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documents with timed ranges of a WAVE file.
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.SS Dolby Metadata
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Dolby metadata appears in Dolby Atmos Master ADM WAVE files.
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Dolby metadata is present in Dolby Atmos master ADM WAVE files.
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.IP dbmd
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Records hints for Dolby playback applications for downmixing, level
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normalization and other things.
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@@ -158,12 +136,10 @@ Region and cue point metadata.
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.IP elm1
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.IP minf
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.IP umid
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Doesn't actually hold a SMPTE UMID!
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.SH HISTORY
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The oldest document that defines the form of a Wave file is the
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.I Multimedia Programming Interface and Data Specifications 1.0
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of August 1991.
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.SH REFERENCES
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(Note: We're not including URLs in this list, the title and standard number
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should be sufficient to find almost all of these documents. The ITU, EBU and
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IETF standards documents are freely-available.)
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.SS Essential File Format
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.TP
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.B Multimedia Programming Interface and Data Specifications 1.0. Microsoft Corporation, 1991.
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@@ -193,16 +169,36 @@ WAVE file to be
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but this is never seen in practice.
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.TP
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.B RFC 2361 \- WAVE and AVI Codec Registries. IETF Network Working Group, 1998.
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Gives a throughly exhaustive list of all of the codecs that Microsoft had
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assigned to vendor WAVE files as of 1998. At the time, numerous hardware
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vendors, sound card and chip manufacturers, sound software developers and
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others all provided their own slightly-different adaptive PCM codecs, linear
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predictive compression codes, DCTs and other things, and Microsoft would issue
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these vendors WAVE codec magic numbers. Almost all of these are no longer in
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use, the only ones one ever encounters in the modern era are integer PCM
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(0x01), floating-point PCM (0x03) and the extended format marker (0xFFFFFFFF).
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There are over a hundred codecs assigned, however, a roll-call of failed
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software and hardware brands.
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Gives an exhaustive list of all of the codecs that Microsoft had assigned to
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vendor WAVE files as of 1998. At the time, numerous hardware vendors, sound
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card and chip manufacturers, sound software developers and others all provided
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their own slightly-different adaptive PCM codecs, linear predictive compression
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codes, DCTs and other things, and Microsoft would issue these vendors WAVE
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codec magic numbers. Almost all of these are no longer in use, the only ones
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one ever encounters in the modern era are integer PCM (0x01), floating-point
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PCM (0x03) and the extended format marker (0xFFFFFFFF). There are over a
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hundred codecs assigned, however, a roll-call of failed software and hardware
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brands.
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.SS Broadcast WAVE Format
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.TP
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.B EBU Tech 3285 \- Specification of the Broadcast Wave Format (BWF). EBU, 2011.
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Defines the elements of a Broadcast WAVE file, the
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.I bext
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metadata chunk structure, allowed sample formats and other things. Over the
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years the EBU has published numerous supplements covering extensions to the
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format, such as embedding SMPTE UMIDs, pre-calculated loudness data (EBU Tech
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3285 v2),
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.I peak
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waveform overview data (Suppl. 3), ADM metadata (Suppl. 5 and 7), Dolby master
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metadata (Suppl. 6), and other things.
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.TP
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.B SMPTE 330M-2011 \- Unique Material Identifier. SMPTE, 2011.
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Describes the format of the SMPTE UMID field, a 32- or 64-byte UUID used to
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identify media files. Broadcast-WAVE files conforming to
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.B "EBU 3285 v2"
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have a SMPTE UMID embedded in the
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.I bext
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chunk.
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.\" .UR https://datatracker.ietf.org/doc/html/rfc2361
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.\" RFC 2361
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.\" .UE
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@@ -1,6 +1,9 @@
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References
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==========
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A complete list of technical references and commentary is available as man page
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and is installed as wavinfo(7) when you install `wavinfo` via pip.
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Wave File Format
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----------------
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