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pschatzmannpschatzmann
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HeaderParserMP3: naming convention lower case field names
1 parent 07166b2 commit 13a8d0d

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‎src/AudioTools/AudioCodecs/HeaderParserMP3.h‎

Lines changed: 49 additions & 49 deletions
Original file line numberDiff line numberDiff line change
@@ -23,7 +23,7 @@ namespace audio_tools {
2323
*/
2424

2525
class HeaderParserMP3 {
26-
// MPEG audio frame header fields parsed from 4 serialized bytes
26+
/// MPEG audio frame header fields parsed from 4 serialized bytes
2727
struct FrameHeader {
2828
static const unsigned int SERIALIZED_SIZE = 4;
2929

@@ -59,18 +59,18 @@ class HeaderParserMP3 {
5959
enum SpecialSampleRate { RESERVED = 0 };
6060

6161
// Parsed fields
62-
MPEGVersionID AudioVersion = MPEGVersionID::INVALID;
63-
LayerID Layer = LayerID::INVALID;
64-
bool Protection = false;
65-
uint8_t BitrateIndex = 0; // 0..15
66-
uint8_t SampleRateIndex = 0; // 0..3
67-
bool Padding = false;
68-
bool Private = false;
69-
ChannelModeID ChannelMode = ChannelModeID::STEREO;
70-
uint8_t ExtentionMode = 0; // 0..3
71-
bool Copyright = false;
72-
bool Original = false;
73-
EmphasisID Emphasis = EmphasisID::NONE;
62+
MPEGVersionID audioVersion = MPEGVersionID::INVALID;
63+
LayerID layer = LayerID::INVALID;
64+
bool protection = false;
65+
uint8_t bitrateIndex = 0; // 0..15
66+
uint8_t sampleRateIndex = 0; // 0..3
67+
bool padding = false;
68+
bool isPrivate = false;
69+
ChannelModeID channelMode = ChannelModeID::STEREO;
70+
uint8_t extensionMode = 0; // 0..3
71+
bool copyright = false;
72+
bool original = false;
73+
EmphasisID emphasis = EmphasisID::NONE;
7474

7575
// Decode 4 bytes into the fields above. Returns false if sync invalid.
7676
static bool decode(const uint8_t* b, FrameHeader& out) {
@@ -81,20 +81,20 @@ class HeaderParserMP3 {
8181
uint8_t b2 = b[2];
8282
uint8_t b3 = b[3];
8383

84-
out.AudioVersion = static_cast<MPEGVersionID>((b1 >> 3) & 0x03);
85-
out.Layer = static_cast<LayerID>((b1 >> 1) & 0x03);
86-
out.Protection = !(b1 & 0x01); // 0 means protected (CRC present)
84+
out.audioVersion = static_cast<MPEGVersionID>((b1 >> 3) & 0x03);
85+
out.layer = static_cast<LayerID>((b1 >> 1) & 0x03);
86+
out.protection = !(b1 & 0x01); // 0 means protected (CRC present)
8787

88-
out.BitrateIndex = (b2 >> 4) & 0x0F;
89-
out.SampleRateIndex = (b2 >> 2) & 0x03;
90-
out.Padding = (b2 >> 1) & 0x01;
91-
out.Private = (b2 & 0x01) != 0;
88+
out.bitrateIndex = (b2 >> 4) & 0x0F;
89+
out.sampleRateIndex = (b2 >> 2) & 0x03;
90+
out.padding = (b2 >> 1) & 0x01;
91+
out.isPrivate = (b2 & 0x01) != 0;
9292

93-
out.ChannelMode = static_cast<ChannelModeID>((b3 >> 6) & 0x03);
94-
out.ExtentionMode = (b3 >> 4) & 0x03;
95-
out.Copyright = (b3 >> 3) & 0x01;
96-
out.Original = (b3 >> 2) & 0x01;
97-
out.Emphasis = static_cast<EmphasisID>(b3 & 0x03);
93+
out.channelMode = static_cast<ChannelModeID>((b3 >> 6) & 0x03);
94+
out.extensionMode = (b3 >> 4) & 0x03;
95+
out.copyright = (b3 >> 3) & 0x01;
96+
out.original = (b3 >> 2) & 0x01;
97+
out.emphasis = static_cast<EmphasisID>(b3 & 0x03);
9898
return true;
9999
}
100100

@@ -145,7 +145,7 @@ class HeaderParserMP3 {
145145
{0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, -1},
146146
},
147147
};
148-
signed char rate_byte = rateTable[(int)AudioVersion][(int)Layer][(int)BitrateIndex];
148+
signed char rate_byte = rateTable[(int)audioVersion][(int)layer][(int)bitrateIndex];
149149
if (rate_byte == -1) {
150150
LOGE("Unsupported bitrate");
151151
return 0;
@@ -166,14 +166,14 @@ class HeaderParserMP3 {
166166
{44100, 48000, 32000, 0},
167167
};
168168

169-
return rateTable[(int)AudioVersion][(int)SampleRateIndex];
169+
return rateTable[(int)audioVersion][(int)sampleRateIndex];
170170
}
171171

172172
int getFrameLength() const {
173173
int sample_rate = getSampleRate();
174174
if (sample_rate == 0) return 0;
175-
int value = (AudioVersion == FrameHeader::MPEGVersionID::MPEG_1) ? 144 : 72;
176-
return int((value * getBitRate() / sample_rate) + (Padding ? 1 : 0));
175+
int value = (audioVersion == FrameHeader::MPEGVersionID::MPEG_1) ? 144 : 72;
176+
return int((value * getBitRate() / sample_rate) + (padding ? 1 : 0));
177177
}
178178
};
179179

@@ -307,7 +307,7 @@ class HeaderParserMP3 {
307307
}
308308

309309
// Check if frame length is reasonable for the given bitrate
310-
int expected_frame_size = (temp_header.AudioVersion == FrameHeader::MPEGVersionID::MPEG_1) ?
310+
int expected_frame_size = (temp_header.audioVersion == FrameHeader::MPEGVersionID::MPEG_1) ?
311311
(144 * temp_header.getBitRate() / temp_header.getSampleRate()) :
312312
(72 * temp_header.getBitRate() / temp_header.getSampleRate());
313313
if (abs(frame_len - expected_frame_size) > expected_frame_size * 0.1) { // Allow 10% variance
@@ -320,8 +320,8 @@ class HeaderParserMP3 {
320320
}
321321
} else {
322322
// Check consistency with first frame (sample rate, version, layer should match in CBR)
323-
if (temp_header.AudioVersion != first_header.AudioVersion ||
324-
temp_header.Layer != first_header.Layer ||
323+
if (temp_header.audioVersion != first_header.audioVersion ||
324+
temp_header.layer != first_header.layer ||
325325
temp_header.getSampleRate() != first_header.getSampleRate()) {
326326
LOGD("Frame parameters inconsistent at position %d", current_pos);
327327
// This might be VBR, but continue validation
@@ -390,9 +390,9 @@ class HeaderParserMP3 {
390390
LOGI("Frame size: %d", getFrameLength());
391391
LOGI("Sample rate: %u", getSampleRate());
392392
LOGI("Bit rate: %d", getBitRate());
393-
LOGI("Padding: %d", getFrameHeader().Padding);
394-
LOGI("Layer: %s (0x%x)", getLayerStr(), (int)getFrameHeader().Layer);
395-
LOGI("Version: %s (0x%x)", getVersionStr(), (int)getFrameHeader().AudioVersion);
393+
LOGI("Padding: %d", getFrameHeader().padding);
394+
LOGI("Layer: %s (0x%x)", getLayerStr(), (int)getFrameHeader().layer);
395+
LOGI("Version: %s (0x%x)", getVersionStr(), (int)getFrameHeader().audioVersion);
396396
LOGI("-------------------");
397397
} else {
398398
LOGI("MP3 validation: INVALID (frames: %d, consecutive: %d, size: %d)",
@@ -416,7 +416,7 @@ class HeaderParserMP3 {
416416
int getChannels() const {
417417
if (!frame_header_valid) return 0;
418418
// SINGLE = mono (1 channel), all others = stereo (2 channels)
419-
return (header.ChannelMode == FrameHeader::ChannelModeID::SINGLE) ? 1 : 2;
419+
return (header.channelMode == FrameHeader::ChannelModeID::SINGLE) ? 1 : 2;
420420
}
421421

422422
/// Frame length from mp3 header
@@ -434,26 +434,26 @@ class HeaderParserMP3 {
434434

435435
/// Provides a string representation of the MPEG version
436436
const char* getVersionStr() const {
437-
return header.AudioVersion == FrameHeader::MPEGVersionID::MPEG_1 ? "1"
438-
: header.AudioVersion == FrameHeader::MPEGVersionID::MPEG_2 ? "2"
439-
: header.AudioVersion == FrameHeader::MPEGVersionID::MPEG_2_5
437+
return header.audioVersion == FrameHeader::MPEGVersionID::MPEG_1 ? "1"
438+
: header.audioVersion == FrameHeader::MPEGVersionID::MPEG_2 ? "2"
439+
: header.audioVersion == FrameHeader::MPEGVersionID::MPEG_2_5
440440
? "2.5"
441441
: "INVALID";
442442
}
443443

444444
/// Provides a string representation of the MPEG layer
445445
const char* getLayerStr() const {
446-
return header.Layer == FrameHeader::LayerID::LAYER_1 ? "1"
447-
: header.Layer == FrameHeader::LayerID::LAYER_2 ? "2"
448-
: header.Layer == FrameHeader::LayerID::LAYER_3 ? "3"
446+
return header.layer == FrameHeader::LayerID::LAYER_1 ? "1"
447+
: header.layer == FrameHeader::LayerID::LAYER_2 ? "2"
448+
: header.layer == FrameHeader::LayerID::LAYER_3 ? "3"
449449
: "INVALID";
450450
}
451451

452452
/// number of samples per mp3 frame
453453
int getSamplesPerFrame() {
454-
if (header.Layer != FrameHeader::LayerID::LAYER_3) return 0;
454+
if (header.layer != FrameHeader::LayerID::LAYER_3) return 0;
455455
// samples for layer 3 are fixed
456-
return header.AudioVersion == FrameHeader::MPEGVersionID::MPEG_1 ? 1152 : 576;
456+
return header.audioVersion == FrameHeader::MPEGVersionID::MPEG_1 ? 1152 : 576;
457457
}
458458

459459
/// playing time per frame in ms
@@ -648,12 +648,12 @@ class HeaderParserMP3 {
648648
};
649649

650650
FrameReason validateFrameHeader(const FrameHeader& header) {
651-
if (header.AudioVersion == FrameHeader::MPEGVersionID::INVALID) {
651+
if (header.audioVersion == FrameHeader::MPEGVersionID::INVALID) {
652652
LOGI("invalid mpeg version");
653653
return FrameReason::INVALID_MPEG_VERSION;
654654
}
655655

656-
if (header.Layer == FrameHeader::LayerID::INVALID) {
656+
if (header.layer == FrameHeader::LayerID::INVALID) {
657657
LOGI("invalid layer");
658658
return FrameReason::INVALID_LAYER;
659659
}
@@ -670,8 +670,8 @@ class HeaderParserMP3 {
670670

671671
// For Layer II there are some combinations of bitrate and mode which are
672672
// not allowed
673-
if (header.Layer == FrameHeader::LayerID::LAYER_2) {
674-
if (header.ChannelMode == FrameHeader::ChannelModeID::SINGLE) {
673+
if (header.layer == FrameHeader::LayerID::LAYER_2) {
674+
if (header.channelMode == FrameHeader::ChannelModeID::SINGLE) {
675675
if (header.getBitRate() >= 224000) {
676676
LOGI("invalid bitrate >224000");
677677
return FrameReason::INVALID_LAYER_II_BITRATE_AND_MODE;
@@ -689,7 +689,7 @@ class HeaderParserMP3 {
689689
}
690690
}
691691

692-
if (header.Emphasis == FrameHeader::EmphasisID::INVALID) {
692+
if (header.emphasis == FrameHeader::EmphasisID::INVALID) {
693693
LOGI("invalid Emphasis");
694694
return FrameReason::INVALID_EMPHASIS;
695695
}

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