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/*
* Copyright 2015, 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_TAG "AudioSPDIF"
//#define LOG_NDEBUG 0
#include <assert.h>
#include <string.h>
#include <log/log.h>
#include <audio_utils/spdif/FrameScanner.h>
#include "BitFieldParser.h"
#include "DTSFrameScanner.h"
namespace android {
// TODO Handle termination frames.
// TODO assert if parse past end of header buffer
// TODO Handle DTS_HD
const uint8_t DTSFrameScanner::kSyncBytes[] =
{ 0x7F, 0xFE, 0x80, 0x01 };
const int32_t DTSFrameScanner::kDTSSampleRateTable[DTS_NUM_SAMPLE_RATE_TABLE_ENTRIES]
= { -1, 8000, 16000, 32000, -1, -1,
11025, 22050, 44100, -1, -1, 12000, 24000, 48000, -1, -1 };
// Defined in IEC61937-2
#define IEC61937_DATA_TYPE_DTS_I 11
#define IEC61937_DATA_TYPE_DTS_II 12
#define IEC61937_DATA_TYPE_DTS_III 13
#define IEC61937_DATA_TYPE_DTS_IV 17
#define IEC61937_MAX_SAMPLES_TYPE_I 512
#define IEC61937_MAX_SAMPLES_TYPE_II 1024
#define IEC61937_MAX_SAMPLES_TYPE_III 2048
// Limits defined in DTS spec paragraph 5.3.1
#define DTS_MINIMUM_NBLKS 5
#define DTS_MINIMUM_FSIZE 95
#define DTS_HEADER_BYTES_NEEDED 12
// Scanner for DTS byte streams.
DTSFrameScanner::DTSFrameScanner()
: FrameScanner(IEC61937_DATA_TYPE_DTS_I,
DTSFrameScanner::kSyncBytes,
sizeof(DTSFrameScanner::kSyncBytes),
DTS_HEADER_BYTES_NEEDED)
, mSampleFramesPerSyncFrame(0)
{
}
DTSFrameScanner::~DTSFrameScanner()
{
}
// Parse DTS header.
// Detect whether the stream is DTS or DTS_HD. Extract data depending on type.
// Sets mDataType, mFrameSizeBytes,
// mSampleRate, mRateMultiplier, mLengthCode.
//
// @return true if valid
bool DTSFrameScanner::parseHeader()
{
BitFieldParser parser(&mHeaderBuffer[mSyncLength]);
// These variables are named after the fields in the DTS spec 5.3.1
// Extract field in order.
(void) /* uint32_t ftype = */ parser.readBits(1);
(void) /* uint32_t deficit = */ parser.readBits(5); // "short"
uint32_t cpf = parser.readBits(1);
uint32_t nblks = parser.readBits(7);
uint32_t fsize = parser.readBits(14);
(void) /* uint32_t amode = */ parser.readBits(6);
uint32_t sfreq = parser.readBits(4);
// make sure we did not read past collected data
ALOG_ASSERT((mSyncLength + ((parser.getBitCursor() + 7) >> 3))
<= mHeaderLength);
// Validate fields.
if (cpf != 0) {
ALOGE("DTSFrameScanner: ERROR - CPF not zero!");
return false;
}
if (nblks < DTS_MINIMUM_NBLKS) {
ALOGE("DTSFrameScanner: ERROR - nblks = %u", nblks);
return false;
}
if (fsize < DTS_MINIMUM_FSIZE) {
ALOGE("DTSFrameScanner: ERROR - fsize = %u", fsize);
return false;
}
int32_t sampleRate = kDTSSampleRateTable[sfreq];
if (sampleRate < 0) {
ALOGE("DTSFrameScanner: ERROR - invalid sampleRate[%u] = %d", sfreq, sampleRate);
return false;
}
mSampleRate = (uint32_t) sampleRate;
mSampleFramesPerSyncFrame = (nblks + 1) * DTS_PCM_FRAMES_PER_BLOCK;
if (mSampleFramesPerSyncFrame <= IEC61937_MAX_SAMPLES_TYPE_I) {
mDataType = IEC61937_DATA_TYPE_DTS_I;
} else if (mSampleFramesPerSyncFrame <= IEC61937_MAX_SAMPLES_TYPE_II) {
mDataType = IEC61937_DATA_TYPE_DTS_II;
} else if (mSampleFramesPerSyncFrame <= IEC61937_MAX_SAMPLES_TYPE_III) {
mDataType = IEC61937_DATA_TYPE_DTS_III;
} else {
mDataType = IEC61937_DATA_TYPE_DTS_IV;
// TODO set bits 8,10
}
mFrameSizeBytes = fsize + 1;
mRateMultiplier = 1; // TODO what about "frequency extension"?
ALOGI_IF((mFormatDumpCount == 0),
"DTS frame rate = %d * %d, size = %zu",
mSampleRate, mRateMultiplier, mFrameSizeBytes);
mFormatDumpCount++;
return true;
}
} // namespace android