发现wav文件的格式解析有点小问题，原因就是不同的软件录制的wav文件里面有一些多余的头，这样就无法保证头的大小为44字节了，所以解析的代码需要注意这一点。我发现早前版本的webrtc里的源码就没有考虑到这一点，在解析ffmpeg转换后的wav文件和苹果录制的wav文件时，就出了问题。请看源码：webrtc/src/common_audio/wav_header.cc文件里的函数ReadWavHeader实现。
本人改写如下：
复制代码
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105bool ReadWavHeader(ReadableWav* readable, int* num_channels, int* sample_rate, WavFormat* format, size_t* bytes_per_sample, size_t* num_samples) { WavHeader header; #if 0 if (readable->Read(&header, kWavHeaderSize - sizeof(header.data)) != kWavHeaderSize - sizeof(header.data)) return false; const uint32_t fmt_size = ReadLE32(header.fmt.header.Size); if (fmt_size != kFmtSubchunkSize) { // There is an optional two-byte extension field permitted to be present // with PCM, but which must be zero. int16_t ext_size; if (kFmtSubchunkSize + sizeof(ext_size) != fmt_size) return false; if (readable->Read(&ext_size, sizeof(ext_size)) != sizeof(ext_size)) return false; if (ext_size != 0) return false; } if (readable->Read(&header.data, sizeof(header.data)) != sizeof(header.data)) return false; #else while (true) { ChunkHeader unknown_header; if (readable->Read(&unknown_header, sizeof(unknown_header)) != sizeof(unknown_header)) return false; std::string fourccID = ReadFourCC(unknown_header.ID); if (fourccID == "RIFF") { header.riff.header = unknown_header; if (readable->Read(&header.riff.Format, sizeof(header.riff.Format)) != sizeof(header.riff.Format)) return false; } else if (fourccID == "fmt ") { header.fmt.header = unknown_header; if (readable->Read(&header.fmt.info, sizeof(header.fmt.info)) != sizeof(header.fmt.info)) return false; const uint32_t fmt_size = ReadLE32(header.fmt.header.Size); if (fmt_size != kFmtSubchunkSize) { // There is an optional two-byte extension field permitted to be present // with PCM, but which must be zero. int16_t ext_size; if (kFmtSubchunkSize + sizeof(ext_size) != fmt_size) return false; if (readable->Read(&ext_size, sizeof(ext_size)) != sizeof(ext_size)) return false; if (ext_size != 0) return false; } } else if (fourccID == "data") { header.data.header = unknown_header; break;//until find data } else// if (fourccID == "LIST")//skip junk/list/fllr if exists { const size_t bytes_in_payload = ReadLE32(unknown_header.Size); if (readable->Seek(bytes_in_payload, SEEK_CUR) != 0) return false; } } #endif // Parse needed fields. *format = static_cast<WavFormat>(ReadLE16(header.fmt.AudioFormat)); *num_channels = ReadLE16(header.fmt.NumChannels); *sample_rate = ReadLE32(header.fmt.SampleRate); *bytes_per_sample = ReadLE16(header.fmt.BitsPerSample) / 8; const size_t bytes_in_payload = ReadLE32(header.data.header.Size); if (*bytes_per_sample == 0) return false; *num_samples = bytes_in_payload / *bytes_per_sample; // Sanity check remaining fields. if (ReadFourCC(header.riff.header.ID) != "RIFF") return false; if (ReadFourCC(header.riff.Format) != "WAVE") return false; if (ReadFourCC(header.fmt.header.ID) != "fmt ") return false; if (ReadFourCC(header.data.header.ID) != "data") return false; if (ReadLE32(header.riff.header.Size) < RiffChunkSize(bytes_in_payload)) return false; if (ReadLE32(header.fmt.ByteRate) != ByteRate(*num_channels, *sample_rate, *bytes_per_sample)) return false; if (ReadLE16(header.fmt.BlockAlign) != BlockAlign(*num_channels, *bytes_per_sample)) return false; return CheckWavParameters(*num_channels, *sample_rate, *format, *bytes_per_sample, *num_samples); }
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以上就是腼腆枕头最近收集整理的关于webrtc中的wav文件格式解析的全部内容，更多相关webrtc中内容请搜索靠谱客的其他文章。
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