mirror of
https://github.com/arcodange-org/mediabunny.git
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34 lines
1.3 KiB
TypeScript
34 lines
1.3 KiB
TypeScript
/*!
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* Copyright (c) 2026-present, Vanilagy and contributors
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/.
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*/
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/** Sample rates the core can be encoded at (Table 5-5) */
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export const DTS_SAMPLE_RATES = [8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000];
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/** Channel counts DTS has a speaker layout for; 3 and 7 have no mapping */
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export const DTS_CHANNEL_COUNTS = [1, 2, 4, 5, 6];
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const DTS_MAX_FRAME_SIZE = 16384;
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/**
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* The DTS encoder needs each frame to be big enough to hold the per-channel side info and rejects the whole
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* configuration when it isn't, so this mirrors the check from FFmpeg's dcaenc.c.
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*/
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export const dtsBitrateFits = (bitrate: number, sampleRate: number, numberOfChannels: number) => {
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if (bitrate < 32000 || bitrate > 3840000) {
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return false;
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}
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const hasLfe = numberOfChannels === 6;
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const fullbandChannels = numberOfChannels - (hasLfe ? 1 : 0);
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const frameBits = 32 * Math.ceil(Math.ceil(bitrate * 512 / sampleRate) / 32);
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const minFrameBits = 132 + (493 + 28 * 32) * fullbandChannels + (hasLfe ? 72 : 0);
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return frameBits >= minFrameBits && frameBits <= 8 * DTS_MAX_FRAME_SIZE;
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};
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