/*
* Copyright (C) 2009 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 "AMRExtractor"
#include <utils/Log.h>
#include "AMRExtractor.h"
#include <media/stagefright/foundation/ADebug.h>
#include <media/stagefright/MediaBufferGroup.h>
#include <media/stagefright/MediaDefs.h>
#include <media/stagefright/MediaErrors.h>
#include <media/stagefright/MetaData.h>
#include <utils/String8.h>
namespace android {
class AMRSource : public MediaTrackHelper {
public:
AMRSource(
DataSourceHelper *source,
AMediaFormat *meta,
bool isWide,
const off64_t *offset_table,
size_t offset_table_length);
virtual media_status_t start();
virtual media_status_t stop();
virtual media_status_t getFormat(AMediaFormat *);
virtual media_status_t read(
MediaBufferHelper **buffer, const ReadOptions *options = NULL);
protected:
virtual ~AMRSource();
private:
DataSourceHelper *mDataSource;
AMediaFormat *mMeta;
bool mIsWide;
off64_t mOffset;
int64_t mCurrentTimeUs;
bool mStarted;
MediaBufferGroup *mGroup;
off64_t mOffsetTable[OFFSET_TABLE_LEN];
size_t mOffsetTableLength;
AMRSource(const AMRSource &);
AMRSource &operator=(const AMRSource &);
};
////////////////////////////////////////////////////////////////////////////////
static size_t getFrameSize(bool isWide, unsigned FT) {
static const size_t kFrameSizeNB[16] = {
95, 103, 118, 134, 148, 159, 204, 244,
39, 43, 38, 37, // SID
0, 0, 0, // future use
0 // no data
};
static const size_t kFrameSizeWB[16] = {
132, 177, 253, 285, 317, 365, 397, 461, 477,
40, // SID
0, 0, 0, 0, // future use
0, // speech lost
0 // no data
};
if (FT > 15 || (isWide && FT > 9 && FT < 14) || (!isWide && FT > 11 && FT < 15)) {
ALOGE("illegal AMR frame type %d", FT);
return 0;
}
size_t frameSize = isWide ? kFrameSizeWB[FT] : kFrameSizeNB[FT];
// Round up bits to bytes and add 1 for the header byte.
frameSize = (frameSize + 7) / 8 + 1;
return frameSize;
}
static media_status_t getFrameSizeByOffset(DataSourceHelper *source,
off64_t offset, bool isWide, size_t *frameSize) {
uint8_t header;
ssize_t count = source->readAt(offset, &header, 1);
if (count == 0) {
return AMEDIA_ERROR_END_OF_STREAM;
} else if (count < 0) {
return AMEDIA_ERROR_IO;
}
unsigned FT = (header >> 3) & 0x0f;
*frameSize = getFrameSize(isWide, FT);
if (*frameSize == 0) {
return AMEDIA_ERROR_MALFORMED;
}
return AMEDIA_OK;
}
static bool SniffAMR(
DataSourceHelper *source, bool *isWide, float *confidence) {
char header[9];
if (source->readAt(0, header, sizeof(header)) != sizeof(header)) {
return false;
}
if (!memcmp(header, "#!AMR\n", 6)) {
if (isWide != nullptr) {
*isWide = false;
}
*confidence = 0.5;
return true;
} else if (!memcmp(header, "#!AMR-WB\n", 9)) {
if (isWide != nullptr) {
*isWide = true;
}
*confidence = 0.5;
return true;
}
return false;
}
AMRExtractor::AMRExtractor(DataSourceHelper *source)
: mDataSource(source),
mInitCheck(NO_INIT),
mOffsetTableLength(0) {
float confidence;
if (!SniffAMR(mDataSource, &mIsWide, &confidence)) {
return;
}
mMeta = AMediaFormat_new();
AMediaFormat_setString(mMeta, AMEDIAFORMAT_KEY_MIME,
mIsWide ? MEDIA_MIMETYPE_AUDIO_AMR_WB : MEDIA_MIMETYPE_AUDIO_AMR_NB);
AMediaFormat_setInt32(mMeta, AMEDIAFORMAT_KEY_CHANNEL_COUNT, 1);
AMediaFormat_setInt32(mMeta, AMEDIAFORMAT_KEY_SAMPLE_RATE, mIsWide ? 16000 : 8000);
off64_t offset = mIsWide ? 9 : 6;
off64_t streamSize;
size_t frameSize, numFrames = 0;
int64_t duration = 0;
if (mDataSource->getSize(&streamSize) == OK) {
while (offset < streamSize) {
status_t status = getFrameSizeByOffset(source, offset, mIsWide, &frameSize);
if (status == ERROR_END_OF_STREAM) {
break;
} else if (status != OK) {
return;
}
if ((numFrames % 50 == 0) && (numFrames / 50 < OFFSET_TABLE_LEN)) {
CHECK_EQ(mOffsetTableLength, numFrames / 50);
mOffsetTable[mOffsetTableLength] = offset - (mIsWide ? 9: 6);
mOffsetTableLength ++;
}
offset += frameSize;
duration += 20000; // Each frame is 20ms
numFrames ++;
}
AMediaFormat_setInt64(mMeta, AMEDIAFORMAT_KEY_DURATION, duration);
}
mInitCheck = OK;
}
AMRExtractor::~AMRExtractor() {
delete mDataSource;
AMediaFormat_delete(mMeta);
}
media_status_t AMRExtractor::getMetaData(AMediaFormat *meta) {
AMediaFormat_clear(meta);
if (mInitCheck == OK) {
AMediaFormat_setString(meta,
AMEDIAFORMAT_KEY_MIME, mIsWide ? MEDIA_MIMETYPE_AUDIO_AMR_WB : "audio/amr");
}
return AMEDIA_OK;
}
size_t AMRExtractor::countTracks() {
return mInitCheck == OK ? 1 : 0;
}
MediaTrackHelper *AMRExtractor::getTrack(size_t index) {
if (mInitCheck != OK || index != 0) {
return NULL;
}
return new AMRSource(mDataSource, mMeta, mIsWide,
mOffsetTable, mOffsetTableLength);
}
media_status_t AMRExtractor::getTrackMetaData(AMediaFormat *meta, size_t index, uint32_t /* flags */) {
if (mInitCheck != OK || index != 0) {
return AMEDIA_ERROR_UNKNOWN;
}
return AMediaFormat_copy(meta, mMeta);
}
////////////////////////////////////////////////////////////////////////////////
AMRSource::AMRSource(
DataSourceHelper *source, AMediaFormat *meta,
bool isWide, const off64_t *offset_table, size_t offset_table_length)
: mDataSource(source),
mMeta(meta),
mIsWide(isWide),
mOffset(mIsWide ? 9 : 6),
mCurrentTimeUs(0),
mStarted(false),
mGroup(NULL),
mOffsetTableLength(offset_table_length) {
if (mOffsetTableLength > 0 && mOffsetTableLength <= OFFSET_TABLE_LEN) {
memcpy ((char*)mOffsetTable, (char*)offset_table, sizeof(off64_t) * mOffsetTableLength);
}
}
AMRSource::~AMRSource() {
if (mStarted) {
stop();
}
}
media_status_t AMRSource::start() {
CHECK(!mStarted);
mOffset = mIsWide ? 9 : 6;
mCurrentTimeUs = 0;
mBufferGroup->add_buffer(128);
mStarted = true;
return AMEDIA_OK;
}
media_status_t AMRSource::stop() {
CHECK(mStarted);
mStarted = false;
return AMEDIA_OK;
}
media_status_t AMRSource::getFormat(AMediaFormat *meta) {
return AMediaFormat_copy(meta, mMeta);
}
media_status_t AMRSource::read(
MediaBufferHelper **out, const ReadOptions *options) {
*out = NULL;
int64_t seekTimeUs;
ReadOptions::SeekMode mode;
if (mOffsetTableLength > 0 && options && options->getSeekTo(&seekTimeUs, &mode)) {
size_t size;
int64_t seekFrame = seekTimeUs / 20000LL; // 20ms per frame.
mCurrentTimeUs = seekFrame * 20000LL;
size_t index = seekFrame < 0 ? 0 : seekFrame / 50;
if (index >= mOffsetTableLength) {
index = mOffsetTableLength - 1;
}
mOffset = mOffsetTable[index] + (mIsWide ? 9 : 6);
for (size_t i = 0; i< seekFrame - index * 50; i++) {
media_status_t err;
if ((err = getFrameSizeByOffset(mDataSource, mOffset,
mIsWide, &size)) != OK) {
return err;
}
mOffset += size;
}
}
uint8_t header;
ssize_t n = mDataSource->readAt(mOffset, &header, 1);
if (n < 1) {
return AMEDIA_ERROR_END_OF_STREAM;
}
if (header & 0x83) {
// Padding bits must be 0.
ALOGE("padding bits must be 0, header is 0x%02x", header);
return AMEDIA_ERROR_MALFORMED;
}
unsigned FT = (header >> 3) & 0x0f;
size_t frameSize = getFrameSize(mIsWide, FT);
if (frameSize == 0) {
return AMEDIA_ERROR_MALFORMED;
}
MediaBufferHelper *buffer;
status_t err = mBufferGroup->acquire_buffer(&buffer);
if (err != OK) {
return AMEDIA_ERROR_UNKNOWN;
}
n = mDataSource->readAt(mOffset, buffer->data(), frameSize);
if (n != (ssize_t)frameSize) {
buffer->release();
buffer = NULL;
if (n < 0) {
return AMEDIA_ERROR_IO;
} else {
// only partial frame is available, treat it as EOS.
mOffset += n;
return AMEDIA_ERROR_END_OF_STREAM;
}
}
buffer->set_range(0, frameSize);
AMediaFormat *meta = buffer->meta_data();
AMediaFormat_setInt64(meta, AMEDIAFORMAT_KEY_TIME_US, mCurrentTimeUs);
AMediaFormat_setInt32(meta, AMEDIAFORMAT_KEY_IS_SYNC_FRAME, 1);
mOffset += frameSize;
mCurrentTimeUs += 20000; // Each frame is 20ms
*out = buffer;
return AMEDIA_OK;
}
////////////////////////////////////////////////////////////////////////////////
static const char *extensions[] = {
"amr",
"awb",
NULL
};
extern "C" {
// This is the only symbol that needs to be exported
__attribute__ ((visibility ("default")))
ExtractorDef GETEXTRACTORDEF() {
return {
EXTRACTORDEF_VERSION,
UUID("c86639c9-2f31-40ac-a715-fa01b4493aaf"),
1,
"AMR Extractor",
{
.v3 = {
[](
CDataSource *source,
float *confidence,
void **,
FreeMetaFunc *) -> CreatorFunc {
DataSourceHelper helper(source);
if (SniffAMR(&helper, nullptr, confidence)) {
return [](
CDataSource *source,
void *) -> CMediaExtractor* {
return wrap(new AMRExtractor(new DataSourceHelper(source)));};
}
return NULL;
},
extensions
},
},
};
}
} // extern "C"
} // namespace android