1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "media/formats/mpeg/adts_stream_parser.h" 6 7 #include "media/formats/mpeg/adts_constants.h" 8 9 namespace media { 10 11 static const uint32 kADTSStartCodeMask = 0xfff00000; 12 13 ADTSStreamParser::ADTSStreamParser() 14 : MPEGAudioStreamParserBase(kADTSStartCodeMask, kCodecAAC, 0) {} 15 16 ADTSStreamParser::~ADTSStreamParser() {} 17 18 int ADTSStreamParser::ParseFrameHeader(const uint8* data, 19 int size, 20 int* frame_size, 21 int* sample_rate, 22 ChannelLayout* channel_layout, 23 int* sample_count, 24 bool* metadata_frame) const { 25 DCHECK(data); 26 DCHECK_GE(size, 0); 27 DCHECK(frame_size); 28 29 if (size < 8) 30 return 0; 31 32 BitReader reader(data, size); 33 int sync; 34 int version; 35 int layer; 36 int protection_absent; 37 int profile; 38 size_t sample_rate_index; 39 size_t channel_layout_index; 40 int frame_length; 41 size_t num_data_blocks; 42 int unused; 43 44 if (!reader.ReadBits(12, &sync) || 45 !reader.ReadBits(1, &version) || 46 !reader.ReadBits(2, &layer) || 47 !reader.ReadBits(1, &protection_absent) || 48 !reader.ReadBits(2, &profile) || 49 !reader.ReadBits(4, &sample_rate_index) || 50 !reader.ReadBits(1, &unused) || 51 !reader.ReadBits(3, &channel_layout_index) || 52 !reader.ReadBits(4, &unused) || 53 !reader.ReadBits(13, &frame_length) || 54 !reader.ReadBits(11, &unused) || 55 !reader.ReadBits(2, &num_data_blocks) || 56 (!protection_absent && !reader.ReadBits(16, &unused))) { 57 return -1; 58 } 59 60 DVLOG(2) << "Header data :" << std::hex 61 << " sync 0x" << sync 62 << " version 0x" << version 63 << " layer 0x" << layer 64 << " profile 0x" << profile 65 << " sample_rate_index 0x" << sample_rate_index 66 << " channel_layout_index 0x" << channel_layout_index; 67 68 const int bytes_read = reader.bits_read() / 8; 69 if (sync != 0xfff || layer != 0 || frame_length < bytes_read || 70 sample_rate_index >= kADTSFrequencyTableSize || 71 channel_layout_index >= kADTSChannelLayoutTableSize) { 72 MEDIA_LOG(log_cb()) << "Invalid header data :" << std::hex 73 << " sync 0x" << sync 74 << " version 0x" << version 75 << " layer 0x" << layer 76 << " sample_rate_index 0x" << sample_rate_index 77 << " channel_layout_index 0x" << channel_layout_index; 78 return -1; 79 } 80 81 if (sample_rate) 82 *sample_rate = kADTSFrequencyTable[sample_rate_index]; 83 84 if (frame_size) 85 *frame_size = frame_length; 86 87 if (sample_count) 88 *sample_count = (num_data_blocks + 1) * kSamplesPerAACFrame; 89 90 if (channel_layout) 91 *channel_layout = kADTSChannelLayoutTable[channel_layout_index]; 92 93 if (metadata_frame) 94 *metadata_frame = false; 95 96 return bytes_read; 97 } 98 99 } // namespace media 100
