pjs/content/media/wave/nsWaveReader.h

95 строки
2.9 KiB
C
Исходник Обычный вид История

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
2012-05-21 15:12:37 +04:00
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#if !defined(nsWaveReader_h_)
#define nsWaveReader_h_
#include "nsBuiltinDecoderReader.h"
class nsBuiltinDecoder;
class nsTimeRanges;
class nsWaveReader : public nsBuiltinDecoderReader
{
public:
nsWaveReader(nsBuiltinDecoder* aDecoder);
~nsWaveReader();
virtual nsresult Init(nsBuiltinDecoderReader* aCloneDonor);
virtual bool DecodeAudioData();
virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
PRInt64 aTimeThreshold);
virtual bool HasAudio()
{
return true;
}
virtual bool HasVideo()
{
return false;
}
virtual nsresult ReadMetadata(nsVideoInfo* aInfo);
virtual nsresult Seek(PRInt64 aTime, PRInt64 aStartTime, PRInt64 aEndTime, PRInt64 aCurrentTime);
virtual nsresult GetBuffered(nsTimeRanges* aBuffered, PRInt64 aStartTime);
// To seek in a buffered range, we just have to seek the stream.
virtual bool IsSeekableInBufferedRanges() {
return true;
}
private:
bool ReadAll(char* aBuf, PRInt64 aSize, PRInt64* aBytesRead = nsnull);
bool LoadRIFFChunk();
bool ScanForwardUntil(PRUint32 aWantedChunk, PRUint32* aChunkSize);
bool LoadFormatChunk();
bool FindDataOffset();
// Returns the number of seconds that aBytes represents based on the
// current audio parameters. e.g. 176400 bytes is 1 second at 16-bit
// stereo 44.1kHz. The time is rounded to the nearest microsecond.
double BytesToTime(PRInt64 aBytes) const;
// Returns the number of bytes that aTime represents based on the current
// audio parameters. e.g. 1 second is 176400 bytes at 16-bit stereo
// 44.1kHz.
PRInt64 TimeToBytes(double aTime) const;
// Rounds aBytes down to the nearest complete audio frame. Assumes
// beginning of byte range is already frame aligned by caller.
PRInt64 RoundDownToFrame(PRInt64 aBytes) const;
PRInt64 GetDataLength();
PRInt64 GetPosition();
/*
Metadata extracted from the WAVE header. Used to initialize the audio
stream, and for byte<->time domain conversions.
*/
// Number of samples per second. Limited to range [100, 96000] in LoadFormatChunk.
PRUint32 mSampleRate;
// Number of channels. Limited to range [1, 2] in LoadFormatChunk.
PRUint32 mChannels;
// Size of a single audio frame, which includes a sample for each channel
// (interleaved).
PRUint32 mFrameSize;
// The sample format of the PCM data.
nsAudioStream::SampleFormat mSampleFormat;
// Size of PCM data stored in the WAVE as reported by the data chunk in
// the media.
PRInt64 mWaveLength;
// Start offset of the PCM data in the media stream. Extends mWaveLength
// bytes.
PRInt64 mWavePCMOffset;
};
#endif