java - 使用 Okio 创建 WAV 文件

Question

我的系统需要使用 WAV 文件数组的字节创建单个 WAV 文件。目前它使用 Okio 在缓冲区上读取和写入数据，然后将数据写入最终文件。

我正在关注此文档和此堆栈溢出问题:

• http://tiny.systems/software/soundProgrammer/WavFormatDocs.pdf
• https://stackoverflow.com/a/12370312/2430555

还有...

• 奥基奥:1.10.0
• Kotlin :1.0.2-1
• Java:1.7

我创建了这段代码:

fun mixAudios() {

    try {

        //Create the file used to storage the mixed audio file.
        val file = File(directory, finalFileName)

        //Open the buffer for this file.
        val bufferedSink = Okio.buffer(Okio.appendingSink(file))

        //Data header of the file.
        val header = Buffer()

        //Data of the file.
        val data = Buffer()

        //Do a action for every audio.
        audios.forEach {

            //Try to read the file, if success, return the file.
            Okio.buffer(Okio.source(File(it.address)))?.let { file ->

                //Create a new buffer for every audio address.
                val buffer = Buffer()

                //Read every byte on the buffer.
                file.readAll(buffer)

                //Remove the first 44 items of the buffer.
                buffer.readByteArray(44)

                //Get the buffer and write every byte on the sink.
                data.writeAll(buffer)

                //Close the sink.
                buffer.close()
                file.close()
            }
        }

        //Count of bytes on the data buffer.
        val fileSize = data.size().toInt()

        //The data is ready to be written on the sink.
        data.close()

        val totalFileSize = fileSize + 36
        val byteRate = (SAMPLE_RATE * CHANNELS * BYTES_PER_SAMPLE) / 8

        //Write the header of the final file.
        header.writeUtf8("RIFF")

            //Write the total file size (with the header)
            .writeByte(totalFileSize and 0xff)
            .writeByte((totalFileSize shr 8) and 0xff)
            .writeByte((totalFileSize shr 16) and 0xff)
            .writeByte((totalFileSize shr 24) and 0xff)
    //      .writeIntLe(fileSize) //Inform the size of the chunk, including the header.

            .writeUtf8("WAVE") //Inform the type of file.
            .writeUtf8("fmt ") //Add the "fmt" letters
            .writeIntLe(samplingRate) //fmt chunk

            .writeByte(AUDIO_FORMAT_PCM) //This byte represents the audio format (PCM).
            .writeByte(0)

            .writeByte(CHANNELS) //This byte represents the channels of the audio.
            .writeByte(0)

            //Write the sample rate
            .writeByte(SAMPLE_RATE and 0xff)
            .writeByte((SAMPLE_RATE shr 8) and 0xff)
            .writeByte((SAMPLE_RATE shr 16) and 0xff)
            .writeByte((SAMPLE_RATE shr 24) and 0xff)
    //      .writeIntLe(SAMPLE_RATE) //The sample rate of the audio

            //Write the byte rate
            .writeByte(byteRate and 0xff)
            .writeByte((byteRate shr 8) and 0xff)
            .writeByte((byteRate shr 16) and 0xff)
            .writeByte((byteRate shr 24) and 0xff)
    //      .writeIntLe((SAMPLE_RATE * CHANNELS * BYTES_PER_SAMPLE) / 8) //Byte rate

            .writeByte(CHANNELS * BYTES_PER_SAMPLE / 8) //Block align
            .writeByte(0)

            .writeByte(BYTES_PER_SAMPLE) //Bytes per sample
            .writeByte(0)

            .writeUtf8("data") //File content size

            .writeByte(fileSize and 0xff)
            .writeByte((fileSize shr 8) and 0xff)
            .writeByte((fileSize shr 16) and 0xff)
            .writeByte((fileSize shr 24) and 0xff)
    //      .writeIntLe(fileSize)

            .close()

        with (bufferedSink) {
            writeAll(header)
            writeAll(data)
            close() //Close and write the file on the memory.
        }

        //Do the rest...

        } catch (e: Exception) {
        if (debugEnabled) {
            e.printStackTrace()
        }
      }
    }

文件已成功生成，但是当我尝试在任何媒体播放器上打开此音频时，它似乎已损坏。

当我尝试探索生成的音频文件的字节时，结果如下所示:

我不知道我写的标题是否正确，你能帮我解决这个问题吗？

谢谢!

Answer 1

您从哪里获取采样率的值？您正在编写 80 3E 00 00(即 16000)，但实际上应该是 10 00 00 00(即原始 PCM 格式的 16)。

此时，您应该在 header 中写入 fmt block 的大小。

希望这能解决您的问题