ulaw_codec_registration.src.html

<pre class='metadata'>
Title: u-law PCM WebCodecs Registration
Repository: w3c/webcodecs
Status: NOTE-ED
Shortname: webcodecs-ulaw-codec-registration
Level: none
Group: mediawg
ED: https://w3c.github.io/webcodecs/ulaw_codec_registration.html
TR: https://www.w3.org/TR/webcodecs-ulaw-codec-registration/
Editor: Chris Cunningham, w3cid 114832, Google Inc. https://www.google.com/
Editor: Paul Adenot, w3cid 62410, Mozilla https://www.mozilla.org/
Editor: Bernard Aboba, w3cid 65611, Microsoft Corporation https://www.microsoft.com/

Abstract: This registration is entered into the [[webcodecs-codec-registry]].
    It describes, for u-law encoded PCM, the (1) fully qualified codec strings,
    (2) the codec-specific {{EncodedAudioChunk}}
    [=EncodedAudioChunk/[[internal data]]=] bytes, (3) the
    {{AudioDecoderConfig.description}} bytes, and (4) the values of
    {{EncodedAudioChunk}} [=EncodedAudioChunk/[[type]]=].

    The registration is not intended to include any information on whether a
    codec format is encumbered by intellectual property claims. Implementers and
    authors are advised to seek appropriate legal counsel in this matter if they
    intend to implement or use a specific codec format. Implementers of
    WebCodecs are not required to support the u-law PCM codec.

    This registration is non-normative.

Markup Shorthands:css no, markdown yes, dfn yes
!Participate: <a href="https://github.com/w3c/webcodecs">Git Repository.</a>
!Participate: <a href="https://github.com/w3c/webcodecs/issues/new">File an issue.</a>
!Version History: <a href="https://github.com/w3c/webcodecs/commits">https://github.com/w3c/webcodecs/commits</a>
</pre>

<pre class='anchors'>
spec: WEBCODECS; urlPrefix: https://w3c.github.io/webcodecs/#
    type: attribute
        text: AudioDecoderConfig.description; url: dom-audiodecoderconfig-description
    type: dfn
        for: EncodedAudioChunkType; text: key; url: dom-encodedaudiochunktype-key
        for: EncodedAudioChunk; text: [[internal data]]; url: dom-encodedaudiochunk-internal-data-slot
        for: EncodedAudioChunk; text: [[type]]; url: dom-encodedaudiochunk-type-slot
    type: interface
        text: EncodedAudioChunk; url: encodedaudiochunk
    type: dictionary
        text: AudioDecoderConfig; url: dictdef-audiodecoderconfig
        text: AudioEncoderConfig; url: dictdef-audioencoderconfig
</pre>

<pre class='biblio'>
{
  "ITU-G.711": {
    "href": "https://www.itu.int/rec/T-REC-G.711/",
    "title": "G.711 : Pulse code modulation (PCM) of voice frequencies",
    "publisher": "ITU",
    "date": "November 1988"
  }
}
</pre>

Fully qualified codec strings {#fully-qualified-codec-strings}
==============================================================

The codec string is `"ulaw"`.

EncodedAudioChunk data {#encodedaudiochunk-data}
================================================

{{EncodedAudioChunk}} [=EncodedAudioChunk/[[internal data]]=] is expected to be
a sequence of bytes of arbitrary length, where each byte is a u-law
encoded PCM sample as defined by Table 2a and 2b in [[ITU-G.711]].

AudioDecoderConfig description {#audiodecoderconfig-description}
================================================================

An {{AudioDecoderConfig.description}} is expected to be omitted from the
{{AudioDecoderConfig}}.

EncodedAudioChunk type {#encodedaudiochunk-type}
================================================

The [=EncodedAudioChunk/[[type]]=] for an {{EncodedAudioChunk}} containing
u-law PCM is always "[=EncodedAudioChunkType/key=]".

Privacy and Security Considerations {#privacy-and-security-considerations}
==========================================================================

Please refer to the [[WEBCODECS#privacy-considerations|Privacy Considerations]]
and [[WEBCODECS#security-considerations|Security Considerations]] sections in
[[WEBCODECS]].