HD terminology
Change-Id: I4bedfa902b65ee98683c400e6bda7bdeecc495d8
diff --git a/src/devices/audio/terminology.jd b/src/devices/audio/terminology.jd
index ba2eb19..1e232b0 100644
--- a/src/devices/audio/terminology.jd
+++ b/src/devices/audio/terminology.jd
@@ -54,6 +54,15 @@
Compare to "gain."
</dd>
+<dt>audiophile</dt>
+<dd>
+An <a href="http://en.wikipedia.org/wiki/Audiophile">audiophile</a>
+is an individual who is concerned with a superior music
+reproduction experience, especially someone willing to make tradeoffs
+(of expense, component size, room design, etc.) beyond what an ordinary
+person might choose.
+</dd>
+
<dt>bits per sample or bit depth</dt>
<dd>
Number of bits of information per sample.
@@ -73,6 +82,24 @@
Compare to "upmixing."
</dd>
+<dt>DSD</dt>
+<dd>
+A proprietary audio encoding based on
+<a href="http://en.wikipedia.org/wiki/Pulse-density_modulation">pulse-density modulation</a>.
+Whereas PCM encodes a waveform as a sequence of individual audio samples of multiple bits,
+DSD encodes a waveform as a sequence of bits at a very high sample rate.
+For DSD, there is no concept of "samples" in the conventional PCM sense.
+Both PCM and DSD represent multiple channels by independent sequences.
+DSD is better suited to content distribution than as an internal representation for processing,
+as it can be difficult to apply traditional DSP algorithms to DSD.
+DSD is used in
+<a href="http://en.wikipedia.org/wiki/Super_Audio_CD">Super Audio CD</a>
+(SACD), and in DSD over PCM (DoP) for USB.
+See the Wikipedia article
+<a href="http://en.wikipedia.org/wiki/Direct_Stream_Digital">Digital Stream Digital<a/>
+for more information.
+</dd>
+
<dt>duck</dt>
<dd>
To temporarily reduce the volume of one stream, when another stream
@@ -99,16 +126,47 @@
Compare to "attenuation."
</dd>
+<dt>HD audio</dt>
+<dd>
+High Definition audio, a synonym for "high-resolution audio".
+Not to be confused with Intel High Definition Audio.
+</dd>
+
<dt>Hz</dt>
<dd>
The units for sample rate or frame rate.
</dd>
+<dt>high-resolution audio</dt>
+<dd>
+There is no standard definition, but high-resolution usually means any representation
+with greater bit-depth and sample rate than CDs (which are stereo 16-bit PCM at 44.1 kHz),
+and with no lossy data compression applied.
+Equivalent to "HD audio". See the Wikipedia article
+<a href="http://en.wikipedia.org/wiki/High-resolution_audio">high-resolution audio</a>
+for more information.
+</dd>
+
<dt>latency</dt>
<dd>
Time delay as a signal passes through a system.
</dd>
+<dt>lossless</dt>
+<dd>
+A <a href="http://en.wikipedia.org/wiki/Lossless_compression">lossless data compression</a>
+algorithm preserves bit accuracy across encoding and decoding.
+The result of decoding any previously encoded data is equivalent to the original data.
+Examples of lossless audio content distribution formats include
+<a href="http://en.wikipedia.org/wiki/Compact_disc">CDs</a>, PCM within
+<a href="http://en.wikipedia.org/wiki/WAV">WAV</a>, and
+<a href="http://en.wikipedia.org/wiki/FLAC">FLAC</a>.
+Note that the authoring process may reduce the bit depth or sample rate from that of the
+<a href="http://en.wikipedia.org/wiki/Audio_mastering">masters</a>.
+Distribution formats that preserve the resolution and bit accuracy of masters
+are the subject of "high-resolution audio".
+</dd>
+
<dt>mono</dt>
<dd>
One channel.
