gecko/content/media/AudioSegment.h
2012-07-30 17:20:58 +03:00

153 lines
4.6 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#ifndef MOZILLA_AUDIOSEGMENT_H_
#define MOZILLA_AUDIOSEGMENT_H_
#include "MediaSegment.h"
#include "nsISupportsImpl.h"
#include "nsAudioStream.h"
#include "SharedBuffer.h"
namespace mozilla {
struct AudioChunk {
typedef nsAudioStream::SampleFormat SampleFormat;
// Generic methods
void SliceTo(TrackTicks aStart, TrackTicks aEnd)
{
NS_ASSERTION(aStart >= 0 && aStart < aEnd && aEnd <= mDuration,
"Slice out of bounds");
if (mBuffer) {
mOffset += PRInt32(aStart);
}
mDuration = aEnd - aStart;
}
TrackTicks GetDuration() const { return mDuration; }
bool CanCombineWithFollowing(const AudioChunk& aOther) const
{
if (aOther.mBuffer != mBuffer) {
return false;
}
if (mBuffer) {
NS_ASSERTION(aOther.mBufferFormat == mBufferFormat && aOther.mBufferLength == mBufferLength,
"Wrong metadata about buffer");
return aOther.mOffset == mOffset + mDuration && aOther.mVolume == mVolume;
}
return true;
}
bool IsNull() const { return mBuffer == nullptr; }
void SetNull(TrackTicks aDuration)
{
mBuffer = nullptr;
mDuration = aDuration;
mOffset = 0;
mVolume = 1.0f;
}
TrackTicks mDuration; // in frames within the buffer
nsRefPtr<SharedBuffer> mBuffer; // null means data is all zeroes
PRInt32 mBufferLength; // number of frames in mBuffer (only meaningful if mBuffer is nonnull)
SampleFormat mBufferFormat; // format of frames in mBuffer (only meaningful if mBuffer is nonnull)
PRInt32 mOffset; // in frames within the buffer (zero if mBuffer is null)
float mVolume; // volume multiplier to apply (1.0f if mBuffer is nonnull)
};
/**
* A list of audio samples consisting of a sequence of slices of SharedBuffers.
* The audio rate is determined by the track, not stored in this class.
*/
class AudioSegment : public MediaSegmentBase<AudioSegment, AudioChunk> {
public:
typedef nsAudioStream::SampleFormat SampleFormat;
static int GetSampleSize(SampleFormat aFormat)
{
switch (aFormat) {
case nsAudioStream::FORMAT_U8: return 1;
case nsAudioStream::FORMAT_S16_LE: return 2;
case nsAudioStream::FORMAT_FLOAT32: return 4;
}
NS_ERROR("Bad format");
return 0;
}
AudioSegment() : MediaSegmentBase<AudioSegment, AudioChunk>(AUDIO), mChannels(0) {}
bool IsInitialized()
{
return mChannels > 0;
}
void Init(PRInt32 aChannels)
{
NS_ASSERTION(aChannels > 0, "Bad number of channels");
NS_ASSERTION(!IsInitialized(), "Already initialized");
mChannels = aChannels;
}
PRInt32 GetChannels()
{
NS_ASSERTION(IsInitialized(), "Not initialized");
return mChannels;
}
/**
* Returns the format of the first audio frame that has data, or
* FORMAT_FLOAT32 if there is none.
*/
SampleFormat GetFirstFrameFormat()
{
for (ChunkIterator ci(*this); !ci.IsEnded(); ci.Next()) {
if (ci->mBuffer) {
return ci->mBufferFormat;
}
}
return nsAudioStream::FORMAT_FLOAT32;
}
void AppendFrames(already_AddRefed<SharedBuffer> aBuffer, PRInt32 aBufferLength,
PRInt32 aStart, PRInt32 aEnd, SampleFormat aFormat)
{
NS_ASSERTION(mChannels > 0, "Not initialized");
AudioChunk* chunk = AppendChunk(aEnd - aStart);
chunk->mBuffer = aBuffer;
chunk->mBufferFormat = aFormat;
chunk->mBufferLength = aBufferLength;
chunk->mOffset = aStart;
chunk->mVolume = 1.0f;
}
void ApplyVolume(float aVolume);
/**
* aOutput must have a matching number of channels, but we will automatically
* convert sample formats.
*/
void WriteTo(nsAudioStream* aOutput);
using MediaSegmentBase<AudioSegment, AudioChunk>::AppendFrom;
void AppendFrom(AudioSegment* aSource)
{
NS_ASSERTION(aSource->mChannels == mChannels, "Non-matching channels");
MediaSegmentBase<AudioSegment, AudioChunk>::AppendFrom(aSource);
}
// Segment-generic methods not in MediaSegmentBase
void InitFrom(const AudioSegment& aOther)
{
NS_ASSERTION(mChannels == 0, "Channels already set");
mChannels = aOther.mChannels;
}
void SliceFrom(const AudioSegment& aOther, TrackTicks aStart, TrackTicks aEnd)
{
InitFrom(aOther);
BaseSliceFrom(aOther, aStart, aEnd);
}
static Type StaticType() { return AUDIO; }
protected:
PRInt32 mChannels;
};
}
#endif /* MOZILLA_AUDIOSEGMENT_H_ */