如何使用javascript将音频文件从.vox格式转换为.mp3格式 [英] How to convert the audio file from .vox format to the .mp3 format using javascript
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问题描述
我有一个.vox格式的音频文件，我希望通过java脚本将其转换为.mp3格式我已经获得了转换代码，但该代码在类文件中意味着在后面结束代码，但我不希望那个通过java脚本我想转换文件。请帮助我。
我尝试过：
I have an audio file which it is in the .vox format and i want to convert that into the .mp3 format through java script i already got the code for the conversion but that code is in class file means that was in back end code,but i don't want that one through java script i want to convert the file.please help me.
What I have tried:
public static void Decode(string inputFile, out string outputFile)
{
outputFile = String.Format("{0}\\{1}.wav", Path.GetDirectoryName(inputFile), Path.GetFileNameWithoutExtension(inputFile));
using (FileStream inputStream = File.Open(@"C:\Users\w-887\Documents\ForUploading\31044316.vox", FileMode.Open))
using (BinaryReader reader = new BinaryReader(inputStream))
using (FileStream outputStream = File.Create(@"C:\Users\w-887\Documents\ForUploading\31044316.mp4"))
using (BinaryWriter writer = new BinaryWriter(outputStream))
{
// Note that 32-bit integer values always take up 4 bytes.
// Note that 16-bit integer values (shorts) always take up 2 bytes.
// Note that HEX values resolve as 32-bit integers unless casted as something else, such as short values.
// ChunkID: "RIFF"
writer.Write(0x46464952);
// ChunkSize: The size of the entire file in bytes minus 8 bytes for the two fields not included in this count: ChunkID and ChunkSize.
writer.Write((int)(reader.BaseStream.Length * 4) + 36);
// Format: "WAVE"
writer.Write(0x45564157);
// Subchunk1ID: "fmt " (with the space).
writer.Write(0x20746D66);
// Subchunk1Size: 16 for PCM.
writer.Write(16);
// AudioFormat: 1 for PCM.
writer.Write((short)1);
// NumChannels: 1 for Mono. 2 for Stereo.
writer.Write((short)1);
// SampleRate: 8000 is usually the default for VOX.
writer.Write(8000);
// ByteRate: SampleRate * NumChannels * BitsPerSample / 8.
writer.Write(12000);
// BlockAlign: NumChannels * BitsPerSample / 8. I rounded this up to 2. It sounds best this way.
writer.Write((short)2);
// BitsPerSample: I will set this as 12 (12 bits per raw output sample as per the VOX specification).
writer.Write((short)12);
// Subchunk2ID: "data"
writer.Write(0x61746164);
// Subchunk2Size: NumSamples * NumChannels * BitsPerSample / 8. You can also think of this as the size of the read of the subchunk following this number.
writer.Write((int)(reader.BaseStream.Length * 4));
// Write the data stream to the file in linear audio.
while (reader.BaseStream.Position != reader.BaseStream.Length)
{
byte b = reader.ReadByte();
float firstDifference = GetDifference((byte)(b / 16));
signal += firstDifference;
writer.Write(TruncateSignalIfNeeded());
float secondDifference = GetDifference((byte)(b % 16));
signal += secondDifference;
writer.Write(TruncateSignalIfNeeded());
}
}
// Response.ContentType = ContentType;
//Response.AppendHeader("Content-Disposition", ("attachment; filename=" + Path.GetFileName(filePath)));
//Response.WriteFile(filePath);
//Response.End()
}
static short TruncateSignalIfNeeded()
{
// Keep signal truncated to 12 bits since, as per the VOX spec, each 4 bit input has 12 output bits.
// Note that 12 bits is 0b111111111111. That's 0xFFF in HEX. That's also 4095 in decimal.
// The sound wave is a signed signal, so factoring in 1 unused bit for the sign, that's 4095/2 rounded down to 2047.
if (signal > 2047)
{
signal = 2047;
}
if (signal < -2047)
{
signal = -2047;
}
return (short)signal;
}
static float GetDifference(byte nibble)
{
int stepSize = GetNextStepSize(nibble);
float difference = ((stepSize * GetBit(nibble, 2)) + ((stepSize / 2) * GetBit(nibble, 1)) + (stepSize / 4 * GetBit(nibble, 0)) + (stepSize / 8));
if (GetBit(nibble, 3) == 1)
{
difference = -difference;
}
return difference;
}
static byte GetBit(byte b, int zeroBasedBitNumber)
{
// Shift the bits to the right by the number of the bit you want to get and then logic AND it with 1 to clear bits trailing to the left of your desired bit.
return (byte)((b >> zeroBasedBitNumber) & 1);
}
static int GetNextStepSize(byte nibble)
{
if (!computedNextStepSizeOnce)
{
computedNextStepSizeOnce = true;
return possibleStepSizes[0];
}
else
{
int magnitude = GetMagnitude(nibble);
if (previousStepSizeIndex + magnitude > 48)
{
previousStepSizeIndex = previousStepSizeIndex + magnitude;
return possibleStepSizes[48];
}
else if (previousStepSizeIndex + magnitude > 0)
{
previousStepSizeIndex = previousStepSizeIndex + magnitude;
return possibleStepSizes[previousStepSizeIndex];
}
else
{
return possibleStepSizes[0];
}
}
}
static int GetMagnitude(byte nibble)
{
if (nibble == 15 || nibble == 7)
return 8;
else if (nibble == 14 || nibble == 6)
return 6;
else if (nibble == 13 || nibble == 5)
return 4;
else if (nibble == 12 || nibble == 4)
return 2;
else
return -1;
}
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