gecko/content/media/AudioSegment.h
Robert O'Callahan 8bd04e7aec Bug 805254. Part 12: Simplify AudioSegment::WriteTo and related code now that the output format is known statically. r=kinetik
Also fixes what I think is a bug in InterleaveAndConvertBuffer converting S16 to S16.
Instead of clamping the volume, we should handle arbitrary volumes by falling back
to the float conversion path.
2012-10-25 23:09:41 +13:00

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3.8 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 "AudioSampleFormat.h"
#include "SharedBuffer.h"
class nsAudioStream;
namespace mozilla {
struct AudioChunk {
typedef mozilla::AudioSampleFormat SampleFormat;
// Generic methods
void SliceTo(TrackTicks aStart, TrackTicks aEnd)
{
NS_ASSERTION(aStart >= 0 && aStart < aEnd && aEnd <= mDuration,
"Slice out of bounds");
if (mBuffer) {
mOffset += int32_t(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
int32_t 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)
int32_t 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 mozilla::AudioSampleFormat SampleFormat;
AudioSegment() : MediaSegmentBase<AudioSegment, AudioChunk>(AUDIO), mChannels(0) {}
bool IsInitialized()
{
return mChannels > 0;
}
void Init(int32_t aChannels)
{
NS_ASSERTION(aChannels > 0, "Bad number of channels");
NS_ASSERTION(!IsInitialized(), "Already initialized");
mChannels = aChannels;
}
int32_t GetChannels()
{
NS_ASSERTION(IsInitialized(), "Not initialized");
return mChannels;
}
void AppendFrames(already_AddRefed<SharedBuffer> aBuffer, int32_t aBufferLength,
int32_t aStart, int32_t 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);
// Segment-generic methods not in MediaSegmentBase
void InitFrom(const AudioSegment& aOther)
{
NS_ASSERTION(mChannels == 0, "Channels already set");
mChannels = aOther.mChannels;
}
void CheckCompatible(const AudioSegment& aOther) const
{
NS_ASSERTION(aOther.mChannels == mChannels, "Non-matching channels");
}
static Type StaticType() { return AUDIO; }
protected:
int32_t mChannels;
};
}
#endif /* MOZILLA_AUDIOSEGMENT_H_ */