Merge "Docs: Restructure Section 5.10" into oc-dev

am: aa1e1864e2

Change-Id: Ic56024fd1dbe6cb3379ddc855f361dec08988cc3

1 files changed, 85 insertions, 60 deletions

diff --git a/5_multimedia/5_10_professional-audio.md b/5_multimedia/5_10_professional-audio.md
index 3fcffd45..e90d0005 100644
--- a/5_multimedia/5_10_professional-audio.md
+++ b/5_multimedia/5_10_professional-audio.md
@@ -1,68 +1,93 @@
 ## 5.10\. Professional Audio
 
-If a device implementation meets _all_ of the following requirements, it is
-STRONGLY RECOMMENDED to report support for feature android.hardware.audio.pro
-via the
-[android.content.pm.PackageManager](http://developer.android.com/reference/android/content/pm/PackageManager.html)
-class.
+If device implementations report support for feature
+`android.hardware.audio.pro` via the
+[android.content.pm.PackageManager](
+http://developer.android.com/reference/android/content/pm/PackageManager.html)
+class, they:
 
-*   The device implementation MUST report support for feature
-android.hardware.audio.low_latency.
-*   The continuous round-trip audio latency, as defined in section 5.6 Audio
-Latency, MUST be 20 milliseconds or less and SHOULD be 10 milliseconds or less
-over at least one supported path.
-*   If the device includes a 4 conductor 3.5mm audio jack, the continuous
-round-trip audio latency MUST be 20 milliseconds or less over the audio jack
-path, and SHOULD be 10 milliseconds or less over the audio jack path.
-*   The device implementation MUST include a USB port(s) supporting USB host
-mode and USB peripheral mode.
-*   The USB host mode MUST implement the USB audio class.
-*   If the device omits a 4 conductor 3.5mm audio jack, the continuous
-round-trip audio latency MUST be 20 milliseconds or less, and SHOULD be
-10 milliseconds or less over the USB host mode port using USB audio class.
-*   If the device includes an HDMI port, the device implementation MUST support
-output in stereo and eight channels at 20-bit or 24-bit depth and 192 kHz
-without bit-depth loss or resampling.
-*   The device implementation MUST report support for feature
-android.software.midi.
-*   If the device includes a 4 conductor 3.5mm audio jack, the device
-implementation is STRONGLY RECOMMENDED to comply with section [Mobile device
-(jack) specifications](https://source.android.com/accessories/headset/specification.html#mobile_device_jack_specifications)
-of the [Wired Audio Headset Specification (v1.1)](https://source.android.com/accessories/headset/specification.html).
-
-Latencies and USB audio requirements MUST be met using the
+*    [C-1-1] MUST report support for feature
+`android.hardware.audio.low_latency`.
+*    [C-1-2] MUST have the continuous round-trip audio latency, as defined in
+[section 5.6 Audio Latency](#5_6_audio_latency), MUST be 20 milliseconds or less and SHOULD be
+10 milliseconds or less over at least one supported path.
+*    [C-1-3] MUST include a USB port(s) supporting USB host mode and USB
+peripheral mode.
+*    [C-1-4] MUST report support for feature `android.software.midi`.
+*    [C-1-5] MUST meet latencies and USB audio requirements using the
 [OpenSL ES](https://developer.android.com/ndk/guides/audio/opensl-for-android.html)
 PCM buffer queue API.
+*    SHOULD provide a sustainable level of CPU performance while audio is active.
+*    SHOULD minimize audio clock inaccuracy and drift relative to standard time.
+*    SHOULD minimize audio clock drift relative to the CPU `CLOCK_MONOTONIC` when both
+are active.
+*    SHOULD minimize audio latency over on-device transducers.
+*    SHOULD minimize audio latency over USB digital audio.
+*    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 inter-channel latency difference.
+*    SHOULD minimize MIDI mean latency over all transports.
+*    SHOULD minimize MIDI latency variability under load (jitter) over all transports.
+*    SHOULD provide accurate MIDI timestamps over all transports.
+*    SHOULD minimize audio signal noise over on-device transducers, including the
+period immediately after cold start.
+*    SHOULD provide zero audio clock difference between the input and output sides of
+corresponding end-points, when both are active. Examples of corresponding
+end-points include the on-device microphone and speaker, or the audio jack input
+and output.
+*    SHOULD handle audio buffer completion callbacks for the input and output sides
+of corresponding end-points on the same thread when both are active, and enter
+the output callback immediately after the return from the input callback.  Or
+if it is not feasible to handle the callbacks on the same thread, then enter the
+output callback shortly after entering the input callback to permit the
+application to have a consistent timing of the input and output sides.
+*    SHOULD minimize the phase difference between HAL audio buffering for the input
+and output sides of corresponding end-points.
+*    SHOULD minimize touch latency.
+*    SHOULD minimize touch latency variability under load (jitter).
+
+If device implementations meet all of the above requirements, they:
+
+*   [SR] STRONGLY RECOMMENDED to report support for feature
+`android.hardware.audio.pro` via the [`android.content.pm.PackageManager`](
+http://developer.android.com/reference/android/content/pm/PackageManager.html)
+class.
 
-Device implementations that meet these requirements via
-the OpenSL ES PCM buffer queue API are STRONGLY RECOMMENDED to also meet the
-same requirements via the
+If device implementations meet the requirements via the OpenSL ES PCM buffer
+queue API, they:
+
+*    [SR] STRONGLY RECOMMENDED to also meet the same requirements via the
 [AAudio](https://developer.android.com/ndk/guides/audio/aaudio/aaudio.html) API.
 
-In addition, a device implementation that reports support for this feature SHOULD:
-
-*   Provide a sustainable level of CPU performance while audio is active.
-*   Minimize audio clock inaccuracy and drift relative to standard time.
-*   Minimize audio clock drift relative to the CPU `CLOCK_MONOTONIC` when both are active.
-*   Minimize audio latency over on-device transducers.
-*   Minimize audio latency over USB digital audio.
-*   Document audio latency measurements over all paths.
-*   Minimize jitter in audio buffer completion callback entry times, as this affects usable percentage of full CPU bandwidth by the callback.
-*   Provide zero audio underruns (output) or overruns (input) under normal use at reported latency.
-*   Provide zero inter-channel latency difference.
-*   Minimize MIDI mean latency over all transports.
-*   Minimize MIDI latency variability under load (jitter) over all transports.
-*   Provide accurate MIDI timestamps over all transports.
-*   Minimize audio signal noise over on-device transducers, including the period immediately after cold start.
-*   Provide zero audio clock difference between the input and output sides of corresponding
-    end-points, when both are active.  Examples of corresponding end-points include
-    the on-device microphone and speaker, or the audio jack input and output.
-*   Handle audio buffer completion callbacks for the input and output sides of corresponding
-    end-points on the same thread when both are active, and enter the output callback immediately
-    after the return from the input callback.  Or if it is not feasible to handle the callbacks
-    on the same thread, then enter the output callback shortly after entering the input callback
-    to permit the application to have a consistent timing of the input and output sides.
-*   Minimize the phase difference between HAL audio buffering for the input and output
-    sides of corresponding end-points.
-*   Minimize touch latency.
-*   Minimize touch latency variability under load (jitter).
+If device implementations include a 4 conductor 3.5mm audio jack, they:
+
+*   [C-2-1] MUST have the continuous round-trip audio latency to be 20
+milliseconds or less over the audio jack path.
+*   [SR] STRONGLY RECOMMENDED to comply with
+section [Mobile device (jack) specifications](
+https://source.android.com/devices/accessories/headset/jack-headset-spec)
+of the [Wired Audio Headset Specification (v1.1)](
+https://source.android.com/devices/accessories/headset/plug-headset-spec).
+*   The continuous round-trip audio latency SHOULD be 10 milliseconds
+or less over the audio jack path.
+
+If device implementations omit a 4 conductor 3.5mm audio jack, they:
+
+*   [C-3-1] MUST have a continuous round-trip audio latency of 20
+milliseconds or less.
+*   The continuous round-trip audio latency SHOULD be 10 milliseconds
+or less over the USB host mode port using USB audio class.
+
+
+If device implementations include a USB port(s) supporting USB host mode, they:
+
+*   [C-4-1] MUST implement the USB audio class.
+
+
+If device implementations include an HDMI port, they:
+
+*   [C-5-1] MUST support output in stereo and eight channels at 20-bit or
+24-bit depth and 192 kHz without bit-depth loss or resampling.