Add local time sync ref (for AbletonLink etc.) selection to SoundManager #14164
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Moved pNewMainClockRef selection out of main loop and added proper handling of setups where only headphones or booth are configured. Simplified fallback mechanisms and removed redundant code. Added unit tests for new function selectLocalTimeSyncRef
JoergAtGithub
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I have probably not yet understand the issue. All of thy syncing is only amatter win which stream padding samples are added. Ony the Master is "clean" and does not need padding samples. The case that could be problematic is the case if the network clock is used and we have passing samples in the Master output. What does AbletonLink do in that case? Which clock is used for syncing AbletonLink devices? |
| AudioPathType::Booth}; | ||
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| SoundDevicePointer pNewLocalTimeSyncRef = nullptr; | ||
| for (const auto& pDevice : std::as_const(devices)) { |
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devices is already const. Did clazy complain?
| } | ||
| QList<AudioOutput> outputs = deviceOutputs[pDevice]; | ||
| for (const auto& type : priorityOrder) { | ||
| auto it = std::find_if(outputs.begin(), |
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I think we can use a const iterator here.
| return out.getType() == type; | ||
| }); | ||
| if (it != outputs.end()) { | ||
| pNewLocalTimeSyncRef = pDevice; |
| // The local time sync reference is the device that is used for the | ||
| // synchronization of processes outside the audio processing engine | ||
| // to the DAC timing of the local sounddevice the DJ hears. | ||
| // This sync reference shall be used for: |
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This comment is missleading. Because for my undertsanding we only have one clock everything is synced too.
pNewLocalTimeSyncRef is only a temporary, right?
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This PR is about selecting the sounddevice that is to be used as reference for external syncronisation. This is the sounddevice with the DAC that generates the sound the DJ hears.
Time syncronization has nothing to do with the clock and this comment section does not contain this term therefore.
Output Latency is specific for each sounddevice and contains various buffers inside and outside of Mixxx. All DAC channels of the same sound-device have the same output-latency, but different sound-devices may have different output-latency. Therefore we need to determine the sound-device that is the reference, before we can gather the correct output-latency.
Logically, the DJ always hears the sound via one of the local PortAudio devices and never via the stream broadcasted over the network. Accordingly, a soundDeviceNetwork can never be useful as a reference for synchronization.
This PR implements the algorithm for determining a synchronization sound-device, that is explicitly selected for time synchronization with functions outside of audio processing in the engine. The synchronization itself, will be added in a follow-up PR.
Everything the DJ hears and sees must be in sync with the local PortAudio sound device, taking into account the full output latency (including the latency contributed by the particular sound API). Even in cases where we use the network clock as reference for the interval of the audio buffer in the engine.
This PR: