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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/formats/mpeg/adts_stream_parser.h"
#include "media/formats/mpeg/adts_constants.h"
namespace media {
static const uint32 kADTSStartCodeMask = 0xfff00000;
ADTSStreamParser::ADTSStreamParser()
: MPEGAudioStreamParserBase(kADTSStartCodeMask, kCodecAAC, 0) {}
ADTSStreamParser::~ADTSStreamParser() {}
int ADTSStreamParser::ParseFrameHeader(const uint8* data,
int size,
int* frame_size,
int* sample_rate,
ChannelLayout* channel_layout,
int* sample_count,
bool* metadata_frame) const {
DCHECK(data);
DCHECK_GE(size, 0);
DCHECK(frame_size);
if (size < 8)
return 0;
BitReader reader(data, size);
int sync;
int version;
int layer;
int protection_absent;
int profile;
size_t sample_rate_index;
size_t channel_layout_index;
int frame_length;
size_t num_data_blocks;
int unused;
if (!reader.ReadBits(12, &sync) ||
!reader.ReadBits(1, &version) ||
!reader.ReadBits(2, &layer) ||
!reader.ReadBits(1, &protection_absent) ||
!reader.ReadBits(2, &profile) ||
!reader.ReadBits(4, &sample_rate_index) ||
!reader.ReadBits(1, &unused) ||
!reader.ReadBits(3, &channel_layout_index) ||
!reader.ReadBits(4, &unused) ||
!reader.ReadBits(13, &frame_length) ||
!reader.ReadBits(11, &unused) ||
!reader.ReadBits(2, &num_data_blocks) ||
(!protection_absent && !reader.ReadBits(16, &unused))) {
return -1;
}
DVLOG(2) << "Header data :" << std::hex
<< " sync 0x" << sync
<< " version 0x" << version
<< " layer 0x" << layer
<< " profile 0x" << profile
<< " sample_rate_index 0x" << sample_rate_index
<< " channel_layout_index 0x" << channel_layout_index;
const int bytes_read = reader.bits_read() / 8;
if (sync != 0xfff || layer != 0 || frame_length < bytes_read ||
sample_rate_index >= kADTSFrequencyTableSize ||
channel_layout_index >= kADTSChannelLayoutTableSize) {
MEDIA_LOG(DEBUG, log_cb())
<< "Invalid header data :" << std::hex << " sync 0x" << sync
<< " version 0x" << version << " layer 0x" << layer
<< " sample_rate_index 0x" << sample_rate_index
<< " channel_layout_index 0x" << channel_layout_index;
return -1;
}
if (sample_rate)
*sample_rate = kADTSFrequencyTable[sample_rate_index];
if (frame_size)
*frame_size = frame_length;
if (sample_count)
*sample_count = (num_data_blocks + 1) * kSamplesPerAACFrame;
if (channel_layout)
*channel_layout = kADTSChannelLayoutTable[channel_layout_index];
if (metadata_frame)
*metadata_frame = false;
return bytes_read;
}
} // namespace media
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