449dbea456
This removes downscaling (halving-add) when multiple voices are being mixed. To avoid clipping, and get similar behavior to before, set the "level" of each voice to (1/voice_count). Slow paths that were applicable to only M0 chips were removed. As a side effect, the internal volume representation is now 0 .. 0x8000 (inclusive), which additionally makes a level of exactly 0.5 representable. Testing performed, on PyGamer: For all 4 data cases, for stereo and mono, for 1 and 2 voices, play pure sign waves represented as RawSamples and view the result on a scope and through headphones. Also, scope the amount of time spent in background tasks. Code size: growth of +272 bytes Performance (time in background task when mixing 2 stereo 16-bit voices): 76us per down from 135us (once per ~2.9ms long term average) (Decrease from 4.7% to 2.4% of all CPU time)
47 lines
1.7 KiB
C
47 lines
1.7 KiB
C
/*
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* This file is part of the Micro Python project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2018 DeanM for Adafruit Industries
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef SHARED_MODULE_AUDIOMIXER_MIXERVOICE_H_
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#define SHARED_MODULE_AUDIOMIXER_MIXERVOICE_H_
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#include "py/obj.h"
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#include "shared-module/audiomixer/__init__.h"
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#include "shared-module/audiomixer/Mixer.h"
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typedef struct {
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mp_obj_base_t base;
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audiomixer_mixer_obj_t *parent;
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mp_obj_t sample;
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bool loop;
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bool more_data;
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uint32_t* remaining_buffer;
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uint32_t buffer_length;
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uint16_t level;
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} audiomixer_mixervoice_obj_t;
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#endif /* SHARED_MODULE_AUDIOMIXER_MIXERVOICE_H_ */
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