mirror of
https://github.com/BililiveRecorder/BililiveRecorder.git
synced 2024-12-25 11:54:43 +08:00
c12ea90b2b
结果就发到正式版里去了,发版之前最后一个加的、测试的最少的功能。 好淦哦
173 lines
6.0 KiB
C#
173 lines
6.0 KiB
C#
using System;
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using System.Buffers.Binary;
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using System.Collections.Generic;
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using System.IO;
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using System.Runtime.CompilerServices;
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using System.Text;
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using BililiveRecorder.Flv.Amf;
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namespace BililiveRecorder.Flv.Writer
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{
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/// <summary>
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/// 输出时用于生成 OnMetaData 中的 keyframes。直接建 object tree 再序列化太太太太慢了
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/// </summary>
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internal class KeyframesScriptDataValue : IScriptDataValue
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{
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/*
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* 最少能保存大约 6300 * 2 second = 3.5 hour 的关键帧索引
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* 如果以 5 秒计算则 6300 * 5 second = 8.75 hour
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*/
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private const int MaxDataCount = 6300;
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private const double MinInterval = 1900;
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private const string Keyframes = "keyframes";
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private const string Times = "times";
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private const string FilePositions = "filepositions";
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private const string Spacer = "spacer";
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private static readonly byte[] EndBytes = new byte[] { 0, 0, 9 };
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private static readonly byte[] TimesBytes = Encoding.UTF8.GetBytes(Times);
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private static readonly byte[] FilePositionsBytes = Encoding.UTF8.GetBytes(FilePositions);
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private static readonly byte[] SpacerBytes = Encoding.UTF8.GetBytes(Spacer);
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public ScriptDataType Type => ScriptDataType.Object;
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private readonly List<Data> KeyframesData = new();
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public void AddData(double time_in_ms, double filePosition)
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{
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var keyframesData = this.KeyframesData;
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if (keyframesData.Count < MaxDataCount && (keyframesData.Count == 0 || ((time_in_ms - keyframesData[keyframesData.Count - 1].Time) > MinInterval)))
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{
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keyframesData.Add(new Data(time: time_in_ms / 1000d, filePosition: filePosition));
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}
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}
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/// <summary>
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/// <see cref="ScriptDataObject.WriteTo(Stream)"/>
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/// <see cref="ScriptDataStrictArray.WriteTo(Stream)"/>
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/// <see cref="ScriptDataNumber.WriteTo(Stream)"/>
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/// </summary>
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/// <param name="stream"></param>
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public void WriteTo(Stream stream)
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{
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stream.WriteByte((byte)this.Type);
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var keyframesData = this.KeyframesData;
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var buffer = new byte[sizeof(double)];
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{
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// key
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WriteKey(stream, TimesBytes);
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// array
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WriteStrictArray(stream, (uint)keyframesData.Count);
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// value
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for (var i = 0; i < keyframesData.Count; i++)
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{
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stream.WriteByte((byte)ScriptDataType.Number);
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BinaryPrimitives.WriteInt64BigEndian(buffer, BitConverter.DoubleToInt64Bits(keyframesData[i].Time));
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stream.Write(buffer);
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}
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}
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{
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// key
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WriteKey(stream, FilePositionsBytes);
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// array
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WriteStrictArray(stream, (uint)keyframesData.Count);
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// value
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for (var i = 0; i < keyframesData.Count; i++)
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{
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stream.WriteByte((byte)ScriptDataType.Number);
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BinaryPrimitives.WriteInt64BigEndian(buffer, BitConverter.DoubleToInt64Bits(keyframesData[i].FilePosition));
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stream.Write(buffer);
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}
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}
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{
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// key
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WriteKey(stream, SpacerBytes);
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// array
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var count = 2u * (uint)(MaxDataCount - keyframesData.Count);
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WriteStrictArray(stream, count);
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// value
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BinaryPrimitives.WriteInt64BigEndian(buffer, BitConverter.DoubleToInt64Bits(double.NaN));
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for (var i = 0; i < count; i++)
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{
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stream.WriteByte((byte)ScriptDataType.Number);
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stream.Write(buffer);
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}
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}
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stream.Write(EndBytes);
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}
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public readonly struct Data
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{
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public readonly double Time;
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public readonly double FilePosition;
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public Data(double time, double filePosition)
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{
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this.Time = time;
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this.FilePosition = filePosition;
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}
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}
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/// <summary>
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/// <see cref="ScriptDataStrictArray.WriteTo(Stream)"/>
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/// </summary>
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/// <param name="stream"></param>
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static unsafe void WriteStrictArray(Stream stream, uint count)
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{
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stream.WriteByte((byte)ScriptDataType.StrictArray);
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var buffer = new byte[sizeof(uint)];
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BinaryPrimitives.WriteUInt32BigEndian(buffer, count);
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stream.Write(buffer);
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}
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/// <summary>
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/// <see cref="ScriptDataObject.WriteTo(Stream)"/>
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/// </summary>
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/// <param name="stream"></param>
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/// <param name="key"></param>
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static void WriteKey(Stream stream, string key)
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{
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var bytes = Encoding.UTF8.GetBytes(key);
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if (bytes.Length > ushort.MaxValue)
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throw new AmfException($"Cannot write more than {ushort.MaxValue} into ScriptDataString");
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var buffer = new byte[sizeof(ushort)];
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BinaryPrimitives.WriteUInt16BigEndian(buffer, (ushort)bytes.Length);
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stream.Write(buffer);
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stream.Write(bytes);
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static void WriteKey(Stream stream, byte[] bytes)
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{
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//if (bytes.Length > ushort.MaxValue)
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// throw new AmfException($"Cannot write more than {ushort.MaxValue} into ScriptDataString");
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var buffer = new byte[sizeof(ushort)];
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BinaryPrimitives.WriteUInt16BigEndian(buffer, (ushort)bytes.Length);
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stream.Write(buffer);
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stream.Write(bytes);
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}
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}
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}
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