49 lines
2.0 KiB
C#
49 lines
2.0 KiB
C#
using System;
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using System.Runtime.InteropServices;
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namespace Discord.Audio.Opus
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{
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internal unsafe class OpusDecoder : OpusConverter
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{
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[DllImport("opus", EntryPoint = "opus_decoder_create", CallingConvention = CallingConvention.Cdecl)]
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private static extern IntPtr CreateDecoder(int Fs, int channels, out OpusError error);
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[DllImport("opus", EntryPoint = "opus_decoder_destroy", CallingConvention = CallingConvention.Cdecl)]
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private static extern void DestroyDecoder(IntPtr decoder);
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[DllImport("opus", EntryPoint = "opus_decode", CallingConvention = CallingConvention.Cdecl)]
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private static extern int Decode(IntPtr st, byte* data, int len, byte[] pcm, int frame_size, int decode_fec);
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public OpusDecoder(int samplingRate)
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: base(samplingRate)
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{
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OpusError error;
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_ptr = CreateDecoder(samplingRate, 2, out error);
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if (error != OpusError.OK)
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throw new InvalidOperationException($"Error occured while creating decoder: {error}");
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}
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/// <summary> Produces PCM samples from Opus-encoded audio. </summary>
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/// <param name="input">PCM samples to decode.</param>
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/// <param name="inputOffset">Offset of the frame in input.</param>
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/// <param name="output">Buffer to store the decoded frame.</param>
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public unsafe int DecodeFrame(byte[] input, int inputOffset, int inputCount, byte[] output)
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{
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int result = 0;
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fixed (byte* inPtr = input)
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result = Decode(_ptr, inPtr + inputOffset, inputCount, output, inputCount, 0);
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if (result < 0)
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throw new Exception(((OpusError)result).ToString());
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return result;
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}
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protected override void Dispose(bool disposing)
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{
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if (_ptr != IntPtr.Zero)
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{
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DestroyDecoder(_ptr);
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_ptr = IntPtr.Zero;
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}
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}
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}
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}
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