diff options
| author | Tim Mayberry <mojofunk@gmail.com> | 2015-11-30 19:21:58 +1000 |
|---|---|---|
| committer | Tim Mayberry <mojofunk@gmail.com> | 2015-12-02 10:24:08 +1000 |
| commit | e9be313c11cb0eafd7fcd2800748ae80be95787f (patch) | |
| tree | be378682147dec50527e1c342d3af83861d9f097 | |
| parent | b4fb1d610b3f4de49c30439de3b5628b8dbf875f (diff) | |
Fix latency compensation for audio data in portaudio backend
For drivers that correctly report latency values(ASIO) this should result a
much closer alignment of audio in a loopback test. Measurement and
adjustment may still be needed, especially for non-ASIO drivers.
Testing with the RME HDSP Multiface and Yamaha AG06 using ASIO drivers results
in maximum offset of a couple of samples.
| -rw-r--r-- | libs/backends/portaudio/portaudio_backend.cc | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/libs/backends/portaudio/portaudio_backend.cc b/libs/backends/portaudio/portaudio_backend.cc index 56e5caf8a2..8443da256a 100644 --- a/libs/backends/portaudio/portaudio_backend.cc +++ b/libs/backends/portaudio/portaudio_backend.cc @@ -1242,12 +1242,19 @@ PortAudioBackend::register_system_audio_ports() const uint32_t a_ins = _n_inputs; const uint32_t a_out = _n_outputs; - // XXX PA reported stream latencies don't match measurements - const uint32_t portaudio_reported_input_latency = _samples_per_period ; // _pcmio->capture_latency(); - const uint32_t portaudio_reported_output_latency = /* _samples_per_period + */ _pcmio->playback_latency(); + uint32_t capture_latency = 0; + uint32_t playback_latency = 0; + + // guard against erroneous latency values + if (_pcmio->capture_latency() > _samples_per_period) { + capture_latency = _pcmio->capture_latency() - _samples_per_period; + } + if (_pcmio->playback_latency() > _samples_per_period) { + playback_latency = _pcmio->playback_latency() - _samples_per_period; + } /* audio ports */ - lr.min = lr.max = portaudio_reported_input_latency + (_measure_latency ? 0 : _systemic_audio_input_latency); + lr.min = lr.max = capture_latency + (_measure_latency ? 0 : _systemic_audio_input_latency); for (uint32_t i = 0; i < a_ins; ++i) { char tmp[64]; snprintf(tmp, sizeof(tmp), "system:capture_%d", i+1); @@ -1260,7 +1267,7 @@ PortAudioBackend::register_system_audio_ports() _system_inputs.push_back (audio_port); } - lr.min = lr.max = portaudio_reported_output_latency + (_measure_latency ? 0 : _systemic_audio_output_latency); + lr.min = lr.max = playback_latency + (_measure_latency ? 0 : _systemic_audio_output_latency); for (uint32_t i = 0; i < a_out; ++i) { char tmp[64]; snprintf(tmp, sizeof(tmp), "system:playback_%d", i+1); |