diff options
| -rw-r--r-- | src/StatsServer.cpp | 12 | ||||
| -rw-r--r-- | src/StatsServer.h | 47 |
2 files changed, 56 insertions, 3 deletions
diff --git a/src/StatsServer.cpp b/src/StatsServer.cpp index eb30ebd..38c4607 100644 --- a/src/StatsServer.cpp +++ b/src/StatsServer.cpp @@ -360,6 +360,9 @@ std::string InputStat::encodeStateJSON() case Unstable: ss << "\"Unstable\""; break; + case Silence: + ss << "\"Silent\""; + break; case Streaming: ss << "\"Streaming\""; break; @@ -400,7 +403,14 @@ input_state_t InputStat::determineState(void) state = Unstable; } else { - state = Streaming; + /* The input is streaming, check if the audio level is too low */ + + if (m_silence_counter > INPUT_AUDIO_LEVEL_SILENCE_COUNT) { + state = Silence; + } + else { + state = Streaming; + } } return state; diff --git a/src/StatsServer.h b/src/StatsServer.h index 1a2993a..731d8ca 100644 --- a/src/StatsServer.h +++ b/src/StatsServer.h @@ -55,6 +55,7 @@ #include <map> #include <boost/thread.hpp> #include <ctime> +#include <math.h> #define MIN_FILL_BUFFER_UNDEF (-1) @@ -66,9 +67,14 @@ enum input_state_t /* The input is waiting for data, all buffers are empty */ NoData, - /* The input is running, but has seen many underruns or overruns */ + /* The input is running, but has seen many underruns or overruns recently */ Unstable, + /* The input is running, but the audio level is too low, or has + * been too low recently + */ + Silence, + /* The input is running stable */ Streaming }; @@ -88,6 +94,21 @@ enum input_state_t */ #define INPUT_NODATA_TIMEOUT 30 // seconds +/* For silence detection, we count the number of occurrences the audio level + * falls below a threshold. + * + * The counter is decreased for each frame that has good audio level. + * + * The counter saturates, and this value defines for how long the + * input will be considered silent after a cut. + * + * If the count reaches a certain value, the input changes state + * to Silence. + */ +#define INPUT_AUDIO_LEVEL_THRESHOLD -50 // dB +#define INPUT_AUDIO_LEVEL_SILENCE_COUNT 100 // superframes (120ms) +#define INPUT_AUDIO_LEVEL_COUNT_SATURATION 500 // superframes (120ms) + /* An example of how the state changes work. * The timeout is set to expire in 30 minutes * at each under-/overrun. @@ -136,6 +157,7 @@ class InputStat m_time_last_buffer_nonempty = 0; m_buffer_empty = true; m_glitch_counter = 0; + m_silence_counter = 0; reset(); } @@ -186,7 +208,27 @@ class InputStat } // State - // TODO add silence detection + + // using the smallest of the two channels + // allows us to detect if only one channel + // is silent. + int minpeak = peak_left < peak_right ? peak_left : peak_right; + + const int16_t int16_max = std::numeric_limits<int16_t>::max(); + int peak_dB = minpeak ? + round(20*log10((double)minpeak / int16_max)) : + -90; + + if (peak_dB < INPUT_AUDIO_LEVEL_THRESHOLD) { + if (m_silence_counter < INPUT_AUDIO_LEVEL_COUNT_SATURATION) { + m_silence_counter++; + } + } + else { + if (m_silence_counter > 0) { + m_silence_counter--; + } + } } void notifyUnderrun(void) @@ -236,6 +278,7 @@ class InputStat /************* STATE ***************/ /* Variables used for determining the input state */ int m_glitch_counter; // saturating counter + int m_silence_counter; // saturating counter time_t m_time_last_event; time_t m_time_last_buffer_nonempty; bool m_buffer_empty; |