shaobin0604
11/24/2011 - 11:18 AM
AACExtractor on Froyo
AACExtractor on Froyo
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//#define LOG_NDEBUG 0
#define LOG_TAG "AACExtractor"
#include <utils/Log.h>
#include "include/AACExtractor.h"
#include <media/stagefright/DataSource.h>
#include <media/stagefright/MediaBufferGroup.h>
#include <media/stagefright/MediaDebug.h>
#include <media/stagefright/MediaDefs.h>
#include <media/stagefright/MediaErrors.h>
#include <media/stagefright/MediaSource.h>
#include <media/stagefright/MetaData.h>
#include <utils/String8.h>
namespace android {
static sp<MetaData> MakeAACCodecSpecificData(
unsigned profile, unsigned sampling_freq_index,
unsigned channel_configuration);
class AACSource : public MediaSource {
public:
AACSource(const sp<DataSource> &source,
const sp<MetaData> &meta,
const Vector<uint64_t> &offset_vector,
int64_t frame_duration_us);
virtual status_t start(MetaData *params = NULL);
virtual status_t stop();
virtual sp<MetaData> getFormat();
virtual status_t read(
MediaBuffer **buffer, const ReadOptions *options = NULL);
protected:
virtual ~AACSource();
private:
static const size_t kMaxFrameSize;
sp<DataSource> mDataSource;
sp<MetaData> mMeta;
off64_t mOffset;
int64_t mCurrentTimeUs;
bool mStarted;
MediaBufferGroup *mGroup;
Vector<uint64_t> mOffsetVector;
int64_t mFrameDurationUs;
AACSource(const AACSource &);
AACSource &operator=(const AACSource &);
};
////////////////////////////////////////////////////////////////////////////////
// Returns the sample rate based on the sampling frequency index
uint32_t get_sample_rate(const uint8_t sf_index)
{
static const uint32_t sample_rates[] =
{
96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000
};
if (sf_index < sizeof(sample_rates) / sizeof(sample_rates[0])) {
return sample_rates[sf_index];
}
return 0;
}
// Returns the frame length in bytes as described in an ADTS header starting at the given offset,
// or 0 if the size can't be read due to an error in the header or a read failure.
// The returned value is the AAC frame size with the ADTS header length (regardless of
// the presence of the CRC).
// If headerSize is non-NULL, it will be used to return the size of the header of this ADTS frame.
static size_t getAdtsFrameLength(const sp<DataSource> &source, off64_t offset, size_t* headerSize) {
const size_t kAdtsHeaderLengthNoCrc = 7;
const size_t kAdtsHeaderLengthWithCrc = 9;
size_t frameSize = 0;
uint8_t syncword[2];
if (source->readAt(offset, &syncword, 2) != 2) {
return 0;
}
if ((syncword[0] != 0xff) || ((syncword[1] & 0xf6) != 0xf0)) {
return 0;
}
uint8_t protectionAbsent;
if (source->readAt(offset + 1, &protectionAbsent, 1) < 1) {
return 0;
}
protectionAbsent &= 0x1;
uint8_t header[3];
if (source->readAt(offset + 3, &header, 3) < 3) {
return 0;
}
frameSize = (header[0] & 0x3) << 11 | header[1] << 3 | header[2] >> 5;
// protectionAbsent is 0 if there is CRC
size_t headSize = protectionAbsent ? kAdtsHeaderLengthNoCrc : kAdtsHeaderLengthWithCrc;
if (headSize > frameSize) {
return 0;
}
if (headerSize != NULL) {
*headerSize = headSize;
}
return frameSize;
}
AACExtractor::AACExtractor(const sp<DataSource> &source)
: mDataSource(source),
mInitCheck(NO_INIT),
mFrameDurationUs(0) {
LOGD("+++++ AACExtractor");
String8 mimeType;
float confidence;
if (!SniffAAC(mDataSource, &mimeType, &confidence)) {
return;
}
uint8_t profile, sf_index, channel, header[2];
if (mDataSource->readAt(2, &header, 2) < 2) {
return;
}
profile = (header[0] >> 6) & 0x3;
sf_index = (header[0] >> 2) & 0xf;
uint32_t sr = get_sample_rate(sf_index);
if (sr == 0) {
return;
}
channel = (header[0] & 0x1) << 2 | (header[1] >> 6);
mMeta = MakeAACCodecSpecificData(profile, sf_index, channel);
off_t offset = 0;
off_t streamSize, numFrames = 0;
size_t frameSize = 0;
int64_t duration = 0;
if (mDataSource->getSize(&streamSize) == OK) {
while (offset < streamSize) {
if ((frameSize = getAdtsFrameLength(source, offset, NULL)) == 0) {
return;
}
mOffsetVector.push(offset);
offset += frameSize;
numFrames ++;
}
// Round up and get the duration
mFrameDurationUs = (1024 * 1000000ll + (sr - 1)) / sr;
duration = numFrames * mFrameDurationUs;
mMeta->setInt64(kKeyDuration, duration);
}
mInitCheck = OK;
LOGD("----- AACExtractor");
}
AACExtractor::~AACExtractor() {
}
sp<MetaData> AACExtractor::getMetaData() {
sp<MetaData> meta = new MetaData;
if (mInitCheck != OK) {
return meta;
}
meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_AAC_ADTS);
return meta;
}
size_t AACExtractor::countTracks() {
return mInitCheck == OK ? 1 : 0;
}
sp<MediaSource> AACExtractor::getTrack(size_t index) {
if (mInitCheck != OK || index != 0) {
return NULL;
}
return new AACSource(mDataSource, mMeta, mOffsetVector, mFrameDurationUs);
}
sp<MetaData> AACExtractor::getTrackMetaData(size_t index, uint32_t flags) {
if (mInitCheck != OK || index != 0) {
return NULL;
}
return mMeta;
}
////////////////////////////////////////////////////////////////////////////////
// 8192 = 2^13, 13bit AAC frame size (in bytes)
const size_t AACSource::kMaxFrameSize = 8192;
AACSource::AACSource(
const sp<DataSource> &source, const sp<MetaData> &meta,
const Vector<uint64_t> &offset_vector,
int64_t frame_duration_us)
: mDataSource(source),
mMeta(meta),
mOffset(0),
mCurrentTimeUs(0),
mStarted(false),
mGroup(NULL),
mOffsetVector(offset_vector),
mFrameDurationUs(frame_duration_us) {
}
AACSource::~AACSource() {
if (mStarted) {
stop();
}
}
status_t AACSource::start(MetaData *params) {
CHECK(!mStarted);
mOffset = 0;
mCurrentTimeUs = 0;
mGroup = new MediaBufferGroup;
mGroup->add_buffer(new MediaBuffer(kMaxFrameSize));
mStarted = true;
return OK;
}
status_t AACSource::stop() {
CHECK(mStarted);
delete mGroup;
mGroup = NULL;
mStarted = false;
return OK;
}
sp<MetaData> AACSource::getFormat() {
return mMeta;
}
status_t AACSource::read(
MediaBuffer **out, const ReadOptions *options) {
*out = NULL;
LOGV("+++++ read");
int64_t seekTimeUs;
if (options && options->getSeekTo(&seekTimeUs)) {
if (mFrameDurationUs > 0) {
int64_t seekFrame = seekTimeUs / mFrameDurationUs;
mCurrentTimeUs = seekFrame * mFrameDurationUs;
mOffset = mOffsetVector.itemAt(seekFrame);
}
}
size_t frameSize, frameSizeWithoutHeader, headerSize;
if ((frameSize = getAdtsFrameLength(mDataSource, mOffset, &headerSize)) == 0) {
return ERROR_END_OF_STREAM;
}
MediaBuffer *buffer;
status_t err = mGroup->acquire_buffer(&buffer);
if (err != OK) {
return err;
}
frameSizeWithoutHeader = frameSize - headerSize;
if (mDataSource->readAt(mOffset + headerSize, buffer->data(),
frameSizeWithoutHeader) != (ssize_t)frameSizeWithoutHeader) {
buffer->release();
buffer = NULL;
return ERROR_IO;
}
buffer->set_range(0, frameSizeWithoutHeader);
buffer->meta_data()->setInt64(kKeyTime, mCurrentTimeUs);
buffer->meta_data()->setInt32(kKeyIsSyncFrame, 1);
mOffset += frameSize;
mCurrentTimeUs += mFrameDurationUs;
*out = buffer;
LOGV("----- read");
return OK;
}
static sp<MetaData> MakeAACCodecSpecificData(
unsigned profile, unsigned sampling_freq_index,
unsigned channel_configuration) {
sp<MetaData> meta = new MetaData;
meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_AAC);
//CHECK_LE(sampling_freq_index, 11u);
static const int32_t kSamplingFreq[] = {
96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050,
16000, 12000, 11025, 8000
};
meta->setInt32(kKeySampleRate, kSamplingFreq[sampling_freq_index]);
meta->setInt32(kKeyChannelCount, channel_configuration);
static const uint8_t kStaticESDS[] = {
0x03, 22,
0x00, 0x00, // ES_ID
0x00, // streamDependenceFlag, URL_Flag, OCRstreamFlag
0x04, 17,
0x40, // Audio ISO/IEC 14496-3
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x05, 2,
// AudioSpecificInfo follows
// oooo offf fccc c000
// o - audioObjectType
// f - samplingFreqIndex
// c - channelConfig
};
#if 1
size_t csdSize = sizeof(kStaticESDS) + 2;
uint8_t* csdData = (uint8_t*)malloc(csdSize);
memcpy(csdData, kStaticESDS, sizeof(kStaticESDS));
csdData[sizeof(kStaticESDS)] =
((profile + 1) << 3) | (sampling_freq_index >> 1);
csdData[sizeof(kStaticESDS) + 1] =
((sampling_freq_index << 7) & 0x80) | (channel_configuration << 3);
meta->setData(kKeyESDS, 0, csdData, csdSize);
free(csdData);
#else
// ABuffer is defined in android-2.3
sp<ABuffer> csd = new ABuffer(sizeof(kStaticESDS) + 2);
memcpy(csd->data(), kStaticESDS, sizeof(kStaticESDS));
csd->data()[sizeof(kStaticESDS)] =
((profile + 1) << 3) | (sampling_freq_index >> 1);
csd->data()[sizeof(kStaticESDS) + 1] =
((sampling_freq_index << 7) & 0x80) | (channel_configuration << 3);
meta->setData(kKeyESDS, 0, csd->data(), csd->size());
#endif
return meta;
}
////////////////////////////////////////////////////////////////////////////////
bool SniffAAC(
const sp<DataSource> &source, String8 *mimeType, float *confidence) {
uint8_t header[2];
if (source->readAt(0, &header, 2) != 2) {
return false;
}
// ADTS syncword
if ((header[0] == 0xff) && ((header[1] & 0xf6) == 0xf0)) {
*mimeType = MEDIA_MIMETYPE_AUDIO_AAC_ADTS;
*confidence = 0.2;
return true;
}
return false;
}
} // namespace android
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef AAC_EXTRACTOR_H_
#define AAC_EXTRACTOR_H_
#include <media/stagefright/MediaExtractor.h>
#include <utils/Vector.h>
namespace android {
struct AMessage;
class String8;
class AACExtractor : public MediaExtractor {
public:
AACExtractor(const sp<DataSource> &source);
virtual size_t countTracks();
virtual sp<MediaSource> getTrack(size_t index);
virtual sp<MetaData> getTrackMetaData(size_t index, uint32_t flags);
virtual sp<MetaData> getMetaData();
protected:
virtual ~AACExtractor();
private:
sp<DataSource> mDataSource;
sp<MetaData> mMeta;
status_t mInitCheck;
Vector<uint64_t> mOffsetVector;
int64_t mFrameDurationUs;
AACExtractor(const AACExtractor &);
AACExtractor &operator=(const AACExtractor &);
};
bool SniffAAC(
const sp<DataSource> &source, String8 *mimeType, float *confidence);
} // namespace android
#endif // AAC_EXTRACTOR_H_