048c5029f5
I discovered the hard way that Adobe Audition writes an 18 byte format header with an extra (zero) extension size field. Although: https://ccrma.stanford.edu/courses/422/projects/WaveFormat/ indicates this field shouldn't exist for PCM, the documentation here: http://www-mmsp.ece.mcgill.ca/documents/AudioFormats/WAVE/WAVE.html doesn't list it as strictly forbidden, only that it _must_ exist for non-PCM formats. Audition can write metadata to the file after the audio data, which is also not forbidden. We now ensure to read only up to the audio payload length to avoid reading the metadata. R=aluebs@webrtc.org, kwiberg@webrtc.org Review URL: https://webrtc-codereview.appspot.com/33629004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@7915 4adac7df-926f-26a2-2b94-8c16560cd09d
65 lines
2.2 KiB
C++
65 lines
2.2 KiB
C++
/*
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* Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_COMMON_AUDIO_WAV_HEADER_H_
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#define WEBRTC_COMMON_AUDIO_WAV_HEADER_H_
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#include <stddef.h>
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#include <stdint.h>
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namespace webrtc {
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static const size_t kWavHeaderSize = 44;
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class ReadableWav {
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public:
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// Returns the number of bytes read.
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size_t virtual Read(void* buf, size_t num_bytes) = 0;
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virtual ~ReadableWav() {}
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};
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enum WavFormat {
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kWavFormatPcm = 1, // PCM, each sample of size bytes_per_sample
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kWavFormatALaw = 6, // 8-bit ITU-T G.711 A-law
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kWavFormatMuLaw = 7, // 8-bit ITU-T G.711 mu-law
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};
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// Return true if the given parameters will make a well-formed WAV header.
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bool CheckWavParameters(int num_channels,
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int sample_rate,
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WavFormat format,
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int bytes_per_sample,
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uint32_t num_samples);
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// Write a kWavHeaderSize bytes long WAV header to buf. The payload that
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// follows the header is supposed to have the specified number of interleaved
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// channels and contain the specified total number of samples of the specified
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// type. CHECKs the input parameters for validity.
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void WriteWavHeader(uint8_t* buf,
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int num_channels,
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int sample_rate,
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WavFormat format,
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int bytes_per_sample,
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uint32_t num_samples);
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// Read a WAV header from an implemented ReadableWav and parse the values into
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// the provided output parameters. ReadableWav is used because the header can
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// be variably sized. Returns false if the header is invalid.
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bool ReadWavHeader(ReadableWav* readable,
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int* num_channels,
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int* sample_rate,
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WavFormat* format,
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int* bytes_per_sample,
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uint32_t* num_samples);
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} // namespace webrtc
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#endif // WEBRTC_COMMON_AUDIO_WAV_HEADER_H_
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