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下午好。抱歉，我的英语不太好。

几天来，我尝试将 WAV 转换为 MP3。为此，我使用 LAME。我可以通过命令提示符使用以下命令转换文件：

lame.exe-B128 - resample 8-mj \ "C: \ \ test.wav \" \ "C: \ \ test.mp3 \"

但我不想通过命令行（为了跨操作系统的可移植性），但我不能在 C++ 中做到这一点（通过 LAME 库）。

这是我的代码：

int main()
{
//...
//...
// extraction of PCM audio data file .wav in file.pcm
short read, write;

FILE *pcm = fopen("file.pcm", "rb");
FILE *mp3 = fopen("file.mp3", "wb");

const int PCM_SIZE = 18424;
const int MP3_SIZE = 13424;

short int pcm_buffer[PCM_SIZE];
unsigned char mp3_buffer[MP3_SIZE];

lame_t lame = lame_init();

if ( lame == NULL ) {
    cout<<"Unable to initialize MP3"<<endl;
    return -1;
}

lame_set_num_channels(lame, 1);
lame_set_in_samplerate(lame, 8000);
lame_set_out_samplerate(lame, 8000);
lame_set_brate(lame, 128);
lame_set_mode(lame, MONO);
lame_set_quality(lame, 2);
lame_set_bWriteVbrTag(lame, 0);
if (( lame_init_params(lame)) < 0) {
    cout << "Unable to initialize MP3 parameters"<<endl;
    return -1;
}

do {
    read = fread(pcm_buffer,sizeof(short), PCM_SIZE, pcm);
    if (read == 0)
        write = lame_encode_flush(lame, mp3_buffer, MP3_SIZE);
    else
        write = lame_encode_buffer_interleaved(lame, pcm_buffer, read, mp3_buffer, MP3_SIZE);
    fwrite(mp3_buffer, write, 1, mp3);
} while (read != 0);

lame_close(lame);
fclose(mp3);
fclose(pcm);

return 0;
}

我得到一个质量很差的 MP3 文件（并且持续时间比原始文件短）。

有什么想法可以解决这个问题吗？

这是我的信息。

Wav:
- Frequency= 8000
- BlocSize= 16
- Canal Nomber= 1 (mono)
- BytePerSec= 16000
- BytePerBloc= 2
- BitsPerSample= 16
- Bitrate= 128
- .wav size: 13466 (ie size of PCM: 13422)

谢谢你。

4

1 回答 1

3 
 @try
 {
int read, write;
FILE *pcm = fopen([cafFilePath cStringUsingEncoding:1], "rb");  //source
fseek(pcm, 4*1024, SEEK_CUR);                                   //skip file header

mp3 = fopen([mp3FilePath cStringUsingEncoding:1], "wb");  //output
const int PCM_SIZE = 8192*3;
const int MP3_SIZE = 8192*3;
short int pcm_buffer[PCM_SIZE*2];
unsigned char mp3_buffer[MP3_SIZE];

lame_t lame = lame_init();
lame_set_in_samplerate(lame, 11025*2);
lame_set_VBR(lame, vbr_default);
lame_init_params(lame);

int nTotalRead=0;

do {
    read = fread(pcm_buffer, 2*sizeof(short int), PCM_SIZE, pcm);

    nTotalRead+=read*4;

    if (read == 0)
        write = lame_encode_flush(lame, mp3_buffer, MP3_SIZE);
    else
        write = lame_encode_buffer_interleaved(lame,pcm_buffer, read, mp3_buffer, MP3_SIZE);
    // write = lame_encode_buffer(lame, pcm_buffer,pcm_buffer, read, mp3_buffer, MP3_SIZE);

    fwrite(mp3_buffer, write, 1, mp3);
} while (read != 0);

lame_close(lame);
fclose(mp3);
fclose(pcm);
}
@catch (NSException *exception)
{
    NSLog(@"%@",[exception description]);
}
于 2013-12-19T10:57:59.400 回答