[PiSink] Allow audio output latency to be set in settings

[pisink] testing: Reduce audio output latency to 50ms

addons/resource.language.en_gb/resources/strings.po

@@ -22047,3 +22047,17 @@ msgstr ""
 msgctxt "#38206"
 msgid "Max"
 msgstr ""
+
+msgctxt "#38191"
+msgid "Audio output latency"
+msgstr ""
+
+#: system/settings/rbp.xml
+msgctxt "#38192"
+msgid "Increase this to protect against underruns, reduce to have lower latency gui sounds"
+msgstr ""
+
+#: system/settings/rbp.xml
+msgctxt "#38193"
+msgid "%i ms"
+msgstr ""

system/settings/rbp.xml

@@ -108,6 +108,18 @@
         <setting id="audiooutput.audiodevice">
           <default>PI:HDMI</default>
         </setting>
+        <setting id="audiooutput.latency" type="integer" label="38191" help="38192">
+          <level>3</level>
+          <default>50</default>
+          <constraints>
+            <minimum>50</minimum>
+            <step>50</step>
+            <maximum>300</maximum>
+          </constraints>
+          <control type="spinner" format="string">
+            <formatlabel>38193</formatlabel>
+          </control>
+        </setting>
         <setting id="audiooutput.plladjust" type="integer" label="38200" help="38201">
           <level>3</level>
           <default>0</default>

xbmc/cores/AudioEngine/Sinks/AESinkPi.cpp

@@ -25,7 +25,6 @@
 #define CLASSNAME "CAESinkPi"
 
 #define NUM_OMX_BUFFERS 2
-#define AUDIO_PLAYBUFFER (0.1) // 100ms
 
 #ifdef OMX_SKIP64BIT
 static inline OMX_TICKS ToOMXTime(int64_t pts)
@@ -45,6 +44,7 @@ CAEDeviceInfo CAESinkPi::m_info;
 
 CAESinkPi::CAESinkPi() :
     m_sinkbuffer_sec_per_byte(0),
+    m_latency(0),
     m_Initialized(false),
     m_submitted(0),
     m_omx_output(NULL),
@@ -213,6 +213,9 @@ bool CAESinkPi::Initialize(AEAudioFormat &format, std::string &device)
   m_initDevice = device;
   m_initFormat = format;
 
+  m_latency = CServiceBroker::GetSettingsComponent()->GetSettings()->GetInt("audiooutput.latency") * 1e-3;
+  m_latency = std::max(m_latency, 50e-3);
+
   const std::string audioDevice = CServiceBroker::GetSettingsComponent()->GetSettings()->GetString(CSettings::SETTING_AUDIOOUTPUT_AUDIODEVICE);
 
   if (m_passthrough || audioDevice == "PI:HDMI")
@@ -238,7 +241,7 @@ bool CAESinkPi::Initialize(AEAudioFormat &format, std::string &device)
   unsigned int sample_size = CAEUtil::DataFormatToBits(format.m_dataFormat) >> 3;
   format.m_frameSize     = sample_size * channels;
   format.m_sampleRate    = std::max(8000U, std::min(192000U, format.m_sampleRate));
-  format.m_frames        = format.m_sampleRate * AUDIO_PLAYBUFFER / NUM_OMX_BUFFERS;
+  format.m_frames        = format.m_sampleRate * m_latency / NUM_OMX_BUFFERS;
 
   m_format = format;
   m_sinkbuffer_sec_per_byte = 1.0 / (double)(m_format.m_frameSize * m_format.m_sampleRate);
@@ -456,7 +459,7 @@ void CAESinkPi::GetDelay(AEDelayStatus& status)
 
 double CAESinkPi::GetCacheTotal()
 {
-  return AUDIO_PLAYBUFFER;
+  return m_latency;
 }
 
 unsigned int CAESinkPi::AddPackets(uint8_t **data, unsigned int frames, unsigned int offset)
@@ -509,8 +512,8 @@ unsigned int CAESinkPi::AddPackets(uint8_t **data, unsigned int frames, unsigned
   m_submitted++;
   GetDelay(status);
   delay = status.GetDelay();
-  if (delay > AUDIO_PLAYBUFFER)
-    KODI::TIME::Sleep(static_cast<int>(1000.0f * (delay - AUDIO_PLAYBUFFER)));
+  if (delay > m_latency)
+    KODI::TIME::Sleep(static_cast<int>(1000.0f * (delay - m_latency)));
   return frames;
 }
 

xbmc/cores/AudioEngine/Sinks/AESinkPi.h

@@ -42,6 +42,7 @@ class CAESinkPi : public IAESink
   AEAudioFormat        m_initFormat;
   AEAudioFormat        m_format;
   double               m_sinkbuffer_sec_per_byte;
+  double               m_latency;
   static CAEDeviceInfo m_info;
   bool                 m_Initialized;
   uint32_t             m_submitted;