Merge "CDD: Add requirements for audio signal integrity" into qt-dev

3 files changed, 135 insertions, 4 deletions

diff --git a/5_multimedia/5_10_professional-audio.md b/5_multimedia/5_10_professional-audio.md
index e9f0f0b0..eaf0537b 100644
--- a/5_multimedia/5_10_professional-audio.md
+++ b/5_multimedia/5_10_professional-audio.md
@@ -45,8 +45,7 @@ when both are active.
 *    SHOULD document audio latency measurements over all paths.
 *    SHOULD minimize jitter in audio buffer completion callback entry times, as this
 affects usable percentage of full CPU bandwidth by the callback.
-*    SHOULD provide zero audio underruns (output) or overruns (input) under normal use
-at reported latency.
+*    SHOULD provide zero audio glitches under normal use at reported latency.
 *    SHOULD provide zero inter-channel latency difference.
 *    SHOULD minimize MIDI mean latency over all transports.
 *    SHOULD minimize MIDI latency variability under load (jitter) over all transports.
diff --git a/5_multimedia/5_6_audio-latency.md b/5_multimedia/5_6_audio-latency.md
index 8f04f1fb..bc14b838 100644
--- a/5_multimedia/5_6_audio-latency.md
+++ b/5_multimedia/5_6_audio-latency.md
@@ -42,6 +42,10 @@ within [Android NDK](https://developer.android.com/ndk/index.html).
 stream and the estimated time when that frame enters or leaves the
 audio processing pipeline on the associated endpoint.  See also
 [AudioTimestamp](https://developer.android.com/reference/android/media/AudioTimestamp).
+*   **glitch**. A temporary interruption or incorrect sample value in the audio signal,
+typically caused by a
+[buffer underrun](https://en.wikipedia.org/wiki/Buffer_underrun) for output,
+buffer overrun for input, or any other source of digital or analog noise.
 
 If device implementations declare `android.hardware.audio.output`, they
 MUST meet or exceed the following requirements:
diff --git a/7_hardware-compatibility/7_8_audio.md b/7_hardware-compatibility/7_8_audio.md
index b1ec1188..689963eb 100644
--- a/7_hardware-compatibility/7_8_audio.md
+++ b/7_hardware-compatibility/7_8_audio.md
@@ -114,5 +114,133 @@ If [`PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND`](
 http://developer.android.com/reference/android/media/AudioManager.html#PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND)
 is "true":
 
-*    [C-2-1] The speaker's mean response in 18.5 kHz - 20 kHz MUST be no lower
-than 40 dB below the response at 2 kHz.
+*    [C-2-1] The speaker's mean response in 18.5 kHz - 20 kHz MUST be no lower than 40 dB below the response at 2 kHz.
+
+### 7.8.4\. Signal Integrity
+
+Device implementations:
+*   SHOULD provide a glitch-free audio signal path for both input
+    and output streams on handheld devices, as defined by zero glitches
+    measured during a test of one minute per path.
+    Test using [OboeTester]
+    (https://github.com/google/oboe/tree/master/apps/OboeTester)
+    “Automated Glitch Test”.
+
+The test requires an [audio loopback dongle]
+(https://source.android.com/devices/audio/latency/loopback),
+used directly in a 3.5mm jack, and/or in combination with a USB-C to 3.5mm adapter.
+All audio output ports SHOULD be tested.
+
+OboeTester currently supports AAudio paths, so the
+following combinations SHOULD be tested for glitches using AAudio:
+
+<table>
+ <tr>
+  <th>Perf Mode
+  <th>Sharing
+  <th>Out Sample Rate
+  <th>In Chans
+  <th>Out Chans
+ </tr>
+ <tr>
+  <td>LOW_LATENCY</td>
+  <td>EXCLUSIVE</td>
+  <td>UNSPECIFIED</td>
+  <td>1</td>
+  <td>2</td>
+ </tr>
+ <tr>
+  <td>LOW_LATENCY</td>
+  <td>EXCLUSIVE</td>
+  <td>UNSPECIFIED</td>
+  <td>2</td>
+  <td>1</td>
+ </tr>
+ <tr>
+  <td>LOW_LATENCY</td>
+  <td>SHARED</td>
+  <td>UNSPECIFIED</td>
+  <td>1</td>
+  <td>2</td>
+ </tr>
+ <tr>
+  <td>LOW_LATENCY</td>
+  <td>SHARED</td>
+  <td>UNSPECIFIED</td>
+  <td>2</td>
+  <td>1</td>
+ </tr>
+ <tr>
+  <td>NONE</td>
+  <td>SHARED</td>
+  <td>48000</td>
+  <td>1</td>
+  <td>2</td>
+ </tr>
+ <tr>
+  <td>NONE</td>
+  <td>SHARED</td>
+  <td>48000</td>
+  <td>2</td>
+  <td>1</td>
+ </tr>
+ <tr>
+  <td>NONE</td>
+  <td>SHARED</td>
+  <td>44100</td>
+  <td>1</td>
+  <td>2</td>
+ </tr>
+ <tr>
+  <td>NONE</td>
+  <td>SHARED</td>
+  <td>44100</td>
+  <td>2</td>
+  <td>1</td>
+ </tr>
+ <tr>
+  <td>NONE</td>
+  <td>SHARED</td>
+  <td>16000</td>
+  <td>1</td>
+  <td>2</td>
+ </tr>
+ <tr>
+  <td>NONE</td>
+  <td>SHARED</td>
+  <td>16000</td>
+  <td>2</td>
+  <td>1</td>
+ </tr>
+</table>
+
+A reliable stream SHOULD meet the following criteria for Signal to Noise
+Ratio (SNR) and Total Harmonic Distortion (THD) for 2000 Hz sine.
+
+<table>
+ <tr>
+  <th>Transducer</th>
+  <th>THD</th>
+  <th>SNR</th>
+ </tr>
+ <tr>
+  <td>primary built-in speaker, measured using an external reference microphone</td>
+  <td>&lt; 3.0%</td>
+  <td>&gt;= 50 dB</td>
+ </tr>
+ <tr>
+  <td>primary built-in microphone, measured using an external reference speaker</td>
+  <td>&lt; 3.0%</td>
+  <td>&gt;= 50 dB</td>
+ </tr>
+ <tr>
+  <td>built-in analog 3.5 mm jacks, tested using loopback adapter</td>
+  <td>&lt; 1%</td>
+  <td>&gt;= 60 dB</td>
+ </tr>
+ <tr>
+  <td>USB adapters supplied with the phone, tested using loopback adapter</td>
+  <td>&lt; 1.0%</td>
+  <td>&gt;= 60 dB</td>
+ </tr>
+</table>