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1 | 1 | ## A Magisk module for maximizing the digital audio fidelity by reducing jitters on audio outputs (USB DACs, Bluetooth a2dp, DLNA, etc.)
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| -So many music lovers abandon audio quality on smart phones and DAP's by believing its causes are delivered from analog components. However, the most crucial cuase of it is actually less than 50Hz jitter (i.e., the standard deviation of actual audio data rate with a low-pass filter; usually converting into time-domain) on digital audio outputs that generates very short reverb or foggy sound like distortion on analog audio outputs. Although more than 50Hz (less than 20msec interval) jitter can be easily reduced under the hearable level by PLL (Phase Locked Loop) in DAC's, the other (especially less than 10Hz or more than 100msec interval) modulates and distorts audio outputs by fluctuating the master clock in a DAC through the PLL. For further explanation, see my another magisk module ["Audio jitter silencer"](https://github.com/Magisk-Modules-Alt-Repo/audio-jitter-silencer). |
| 3 | +So many music lovers abandon audio quality on smart phones and DAP's by believing its causes are delivered from analog components. However, the most crucial cuase of it is actually shorter than 50 Hz jitter (i.e., the standard deviation of actual audio data rate with a low-pass filter; usually converting into time-domain) on digital audio outputs that generates very short reverb or foggy sound like distortion on analog audio outputs. Although more than 50 Hz (shorter than 20 msec. interval) jitter can be easily reduced under the hearable level by a PLL (Phase Locked Loop) in DAC's, the other (especially less than 10 Hz or longer than 100 msec. interval) modulates and distorts audio outputs by fluctuating the master clock in a DAC through the PLL. For further explanation, see my another magisk module ["Audio jitter silencer"](https://github.com/Magisk-Modules-Alt-Repo/audio-jitter-silencer). |
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| -For maximizing the audio fidelity, this module reduces less than 50Hz (more than 20msec interval) jitters on digital audio outputs by optimizing kenel tunables (CPU & GPU governors, thermal control, CPU hotplug, I/O scheduler, Virtual memory), Selinux mode, WIFI parameters, etc. as follows, |
| 5 | +For maximizing the audio fidelity, this module reduces less than 50 Hz (longer than 20 msec interval) jitters on digital audio outputs by optimizing kenel tunables (CPU & GPU governors, thermal control, CPU hotplug, I/O scheduler, Virtual memory), Selinux mode, WIFI parameters, etc. as follows, |
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7 | 7 | * For Reducing Jitters:
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8 | 8 | <ol type="1">
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@@ -64,7 +64,7 @@ For maximizing the audio fidelity, this module reduces less than 50Hz (more than
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65 | 65 | * Don't use Am@zon music using a much worse internal re-sampler which bypasses the mastering quality re-sampling in the OS mixer (audioFlinger). Other music streaming services don't use such an internal re-sampler, as far as I know.
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| -* This module has been tested on LineageOS and ArrowOS ROM's, and phh GSI's (Android 10 ~ 13, Qualcomm & MediaTek SoC, and Arm32 & Arm64 combinations). |
| 67 | +* This module has been tested on LineageOS and crDroid ROM's, and phh GSI's (Android 10 ~ 14, Qualcomm & MediaTek SoC, and Arm32 & Arm64 combinations). |
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69 | 69 | * Note: Entry class USB DAC's usually adopt an interface chip communicating with the adaptive mode or the synchronous one defined in the USB audio standard. As in these modes an Android host controller sends audio sampling rate clock signals to the DAC, jitter generated at the host side affects the audio quality of the DAC tremendously. Higher class DAC's communicate with the asynchronous mode (also defined in the standard) to a host controller, but they actually use a PLL to reduce jitter from the host not to stutter even in heavy jitter situations. As this result, they behave as the adaptive mode with a feedback loop to dynamically adjust the host side sampling clock signals while referring a DAC side clock in a real sense, so even with asynchronous mode they are more or less affected by host side jitter. You can see the mode of your USB DAC by opening "/proc/asound/card1/stream0" on your phone while playing music. Please see a word in parentheses at "Endpoint:" lines; "SYNC", "ADAPTIVE" or "ASYNC" means that your DAC uses "synchronous", "adaptive" or "asynchronous" mode to communicate to your phone, respectively. Moreover, almost all audio peripherals, e.g., bluetooth earphones, internal DAC's, network audio devices have a PLL in themselves and are affected by host side jitter for the same reason.
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