/// <summary>
/// 重采样--指针
/// </summary>
/// <param name="channelDataSegment">重采样数据段信息</param>
private void PrimitiveResample(ChannelDataSegment channelDataSegment)
{
try
{
int sample = channelDataSegment.Sample;
int length = channelDataSegment.EndIndex - channelDataSegment.BegeinIndex;
int segmentTargetCount = length / sample;
if (length % sample != 0)
{
segmentTargetCount += 1;
}
segmentTargetCount = segmentTargetCount * 2;
short[] result = new short[segmentTargetCount];
short[] srcData = channelDataSegment.SrcData;
if (length <= segmentTargetCount)
{
if (length != result.Length)
{
result = new short[length];
}
Array.Copy(srcData, channelDataSegment.BegeinIndex, result, 0, result.Length);
}
else
{
short lMaxValue, lMinValue;
short tmpValue;
int position = 0;
int i, innerEndIndex;
int endIndex = channelDataSegment.EndIndex;
int currentEndIndex;
if (channelDataSegment.Flag)
{
currentEndIndex = endIndex - sample;
}
else
{
currentEndIndex = endIndex;
}
for (i = channelDataSegment.BegeinIndex; i < currentEndIndex; i += sample)
{
innerEndIndex = i + sample;
lMaxValue = srcData[i];
lMinValue = lMaxValue;
for (int j = i + 1; j < innerEndIndex; j++)
{
tmpValue = srcData[j];
if (tmpValue > lMaxValue)
{
lMaxValue = tmpValue;
}
else if (tmpValue < lMinValue)
{
lMinValue = tmpValue;
}
}
result[position] = lMinValue;
result[position + 1] = lMaxValue;
position += 2;
}
if (channelDataSegment.Flag)
{
//最后 一次
innerEndIndex = i;
if (innerEndIndex > endIndex)
{
innerEndIndex = endIndex;
}
i -= sample;
position -= 2;
lMaxValue = srcData[i];
lMinValue = lMaxValue;
for (int j = i + 1; j < innerEndIndex; j++)
{
tmpValue = srcData[j];
if (tmpValue > lMaxValue)
{
lMaxValue = tmpValue;
}
else if (tmpValue < lMinValue)
{
lMinValue = tmpValue;
}
}
if (position >= 0)
{
result[position] = lMinValue;
result[position + 1] = lMaxValue;
}
}
}
channelDataSegment.Result = result;
}
catch (Exception ex)
{
Loger.Error(ex);
}
}
/// <summary>
/// 对声道FFT数据进行重采样
/// </summary>
/// <param name="targetCount">目标数据个数</param>
/// <param name="begeinIndex">原始数据起始索引</param>
/// <param name="endIndex">原始数据结束索引</param>
/// <returns>FFT中最大值</returns>
internal short[] PrimitiveResample(int targetCount, int begeinIndex, int endIndex)
{
if (this._pcmData == null || targetCount >= this._pcmData.Length)
{
return(this._pcmData);
}
int srcCount = endIndex - begeinIndex;//原始数据个数
if (srcCount <= 0)
{
return(new short[0]);
}
int sampleCount; //采样数据个数
bool addinFlag = targetCount > srcCount; //是否需要重采样添加数据
if (addinFlag)
{
sampleCount = (int)srcCount;
}
else
{
sampleCount = targetCount;
}
int sampleSegmentCount = sampleCount / 2; //采样段数,因为是一段数据中取出最大值和最小值,所以目标点数除以2
if (sampleCount % 2 != 0) //如果目标数据个数为奇数,则采样个数+1
{
sampleSegmentCount++;
}
short[] result;
int reSample = srcCount / sampleSegmentCount; //采样率
if (reSample == 0) //如果采样率为0,则总的数据个数少于目标个数,则直接将原始数据拷贝到目标数组
{
result = new short[sampleCount];
Array.Copy(this._pcmData, begeinIndex, result, 0, result.Length);
return(result);
}
if (srcCount % sampleSegmentCount != 0)
{
reSample++;
}
int processorCount = Environment.ProcessorCount; //CPU核心数
int coreSampleSegmentCount = sampleSegmentCount / processorCount; //每一核分配到的采样段个数
if (sampleSegmentCount % processorCount != 0)
{
coreSampleSegmentCount++;
}
//计算数据段大小
int segDataSize = coreSampleSegmentCount * reSample;//采样数据段大小
//拆分数据段
List <ChannelDataSegment> segments = new List <ChannelDataSegment>();
int startIndex = begeinIndex;
for (int i = 0; i < processorCount; i++)
{
ChannelDataSegment channelDataSegment = new ChannelDataSegment();
channelDataSegment.SrcData = this._pcmData;
channelDataSegment.Sample = reSample;
//计算索引位置
channelDataSegment.BegeinIndex = startIndex;
channelDataSegment.EndIndex = startIndex + segDataSize;
if (channelDataSegment.EndIndex > endIndex)
{
channelDataSegment.Flag = true;
channelDataSegment.EndIndex = endIndex;
}
else
{
channelDataSegment.Flag = false;
}
segments.Add(channelDataSegment);
//更新起始索引位置
startIndex = channelDataSegment.EndIndex;
}
//并行处理
Parallel.ForEach(segments, this.PrimitiveResample);
//foreach (var segment in segments)
//{
// this.RepeatSample(segment);
//}
//拼接数据
var resultLength = segments.Sum((item) => { return(item.Result.Length); });
result = new short[resultLength];
int dstIndex = 0;
foreach (var segment in segments)
{
Array.Copy(segment.Result, 0, result, dstIndex, segment.Result.Length);
dstIndex += segment.Result.Length;
}
return(result);
}