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ALSA: allow to measure & set systemic audio latency w/o restart. 

(MIDI needs a bit more work)
This commit is contained in:
Robin Gareus 2015-12-04 17:45:49 +01:00
parent 2529b9db96
commit ac075560bd
2 changed files with 58 additions and 3 deletions
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56
libs/backends/alsa/alsa_audiobackend.cc
View File

@ -483,6 +483,9 @@ int
AlsaAudioBackend::set_systemic_input_latency (uint32_t sl)
{
_systemic_audio_input_latency = sl;
if (_run) {
update_systemic_audio_latencies();
}
return 0;
}
@ -490,6 +493,9 @@ int
AlsaAudioBackend::set_systemic_output_latency (uint32_t sl)
{
_systemic_audio_output_latency = sl;
if (_run) {
update_systemic_audio_latencies();
}
return 0;
}
@ -499,6 +505,9 @@ AlsaAudioBackend::set_systemic_midi_input_latency (std::string const device, uin
struct AlsaMidiDeviceInfo * nfo = midi_device_info(device);
if (!nfo) return -1;
nfo->systemic_input_latency = sl;
if (_run && nfo->enabled) {
update_systemic_midi_latencies ();
}
return 0;
}
@ -508,9 +517,49 @@ AlsaAudioBackend::set_systemic_midi_output_latency (std::string const device, ui
struct AlsaMidiDeviceInfo * nfo = midi_device_info(device);
if (!nfo) return -1;
nfo->systemic_output_latency = sl;
if (_run && nfo->enabled) {
update_systemic_midi_latencies ();
}
return 0;
}
void
AlsaAudioBackend::update_systemic_audio_latencies ()
{
const uint32_t lcpp = (_periods_per_cycle - 2) * _samples_per_period;
LatencyRange lr;
lr.min = lr.max = lcpp + (_measure_latency ? 0 : _systemic_audio_input_latency);
for (std::vector<AlsaPort*>::const_iterator it = _system_outputs.begin (); it != _system_outputs.end (); ++it) {
set_latency_range (*it, true, lr);
}
lr.min = lr.max = (_measure_latency ? 0 : _systemic_audio_output_latency);
for (std::vector<AlsaPort*>::const_iterator it = _system_inputs.begin (); it != _system_inputs.end (); ++it) {
set_latency_range (*it, false, lr);
}
update_latencies ();
}
void
AlsaAudioBackend::update_systemic_midi_latencies ()
{
#if 0
// TODO, need a way to associate the port with the corresponding AlsaMidiDeviceInfo
for (std::vector<AlsaPort*>::iterator it = _system_midi_out.begin (); it != _system_midi_out.end (); ++it) {
LatencyRange lr;
lr.min = lr.max = (_measure_latency ? 0 : nfo->systemic_output_latency);
set_latency_range (*it, false, lr);
}
for (std::vector<AlsaPort*>::const_iterator it = _system_midi_in.begin (); it != _system_midi_in.end (); ++it) {
LatencyRange lr;
lr.min = lr.max = (_measure_latency ? 0 : nfo->systemic_input_latency);
set_latency_range (*it, true, lr);
}
#endif
update_latencies ();
}
/* Retrieving parameters */
std::string
AlsaAudioBackend::device_name () const
@ -679,6 +728,7 @@ AlsaAudioBackend::set_midi_device_enabled (std::string const device, bool enable
struct AlsaMidiDeviceInfo * nfo = midi_device_info(device);
if (!nfo) return -1;
nfo->enabled = enable;
// TODO - trigger update when already running
return 0;
}
@ -1236,7 +1286,7 @@ AlsaAudioBackend::register_system_audio_ports()
const int a_ins = _n_inputs;
const int a_out = _n_outputs;
// TODO set latency depending on _periods_per_cycle and _samples_per_period
const uint32_t lcpp = (_periods_per_cycle - 2) * _samples_per_period;
/* audio ports */
lr.min = lr.max = (_measure_latency ? 0 : _systemic_audio_input_latency);
@ -1249,7 +1299,7 @@ AlsaAudioBackend::register_system_audio_ports()
_system_inputs.push_back(static_cast<AlsaPort*>(p));
}
lr.min = lr.max = (_measure_latency ? 0 : _systemic_audio_output_latency);
lr.min = lr.max = lcpp + (_measure_latency ? 0 : _systemic_audio_output_latency);
for (int i = 1; i <= a_out; ++i) {
char tmp[64];
snprintf(tmp, sizeof(tmp), "system:playback_%d", i);
@ -1311,7 +1361,7 @@ AlsaAudioBackend::register_system_midi_ports()
}
LatencyRange lr;
lr.min = lr.max = (_measure_latency ? 0 : nfo->systemic_output_latency);
set_latency_range (p, false, lr);
set_latency_range (p, true, lr);
static_cast<AlsaMidiPort*>(p)->set_n_periods(_periods_per_cycle); // TODO check MIDI alignment
_system_midi_out.push_back(static_cast<AlsaPort*>(p));
_rmidi_out.push_back (mout);

5
libs/backends/alsa/alsa_audiobackend.h
View File

@ -184,6 +184,8 @@ class AlsaAudioBackend : public AudioBackend {
bool can_change_sample_rate_when_running () const;
bool can_change_buffer_size_when_running () const;
bool can_change_systemic_latency_when_running () const { return true; }
int set_device_name (const std::string&);
int set_input_device_name (const std::string&);
int set_output_device_name (const std::string&);
@ -443,6 +445,9 @@ class AlsaAudioBackend : public AudioBackend {
return NULL;
}
void update_systemic_audio_latencies ();
void update_systemic_midi_latencies ();
}; // class AlsaAudioBackend
} // namespace