Add MP3 check

Source/MediocreMapAssistant2/BPFileIO.cpp

@@ -38,6 +38,159 @@ bool UBPFileIO::VerifyDirectory(const FString & TestDir)
 	return true;
 }
 
+uint8 getMpegVersion(uint8 num) {
+
+	/*
+	 00 - MPEG Version 2.5 (unofficial)
+	 01 - reserved
+	 10 - MPEG Version 2 (ISO/IEC 13818-3)
+	 11 - MPEG Version 1 (ISO/IEC 11172-3)
+	 */
+
+	if ((num & 0x03) == 0x03) {
+		return 1;
+	}
+
+	if ((num & 0x02) == 0x02) {
+		return 2;
+	}
+
+	return 0;
+}
+
+uint8 getMpegLayer(uint8 num) {
+
+	/**
+	 00 - reserved
+	 01 - Layer III
+	 10 - Layer II
+	 11 - Layer I
+	*/
+
+	if ((num & 0x03) == 0x03) {
+		return 1;
+	}
+
+	if ((num & 0x02) == 0x02) {
+		return 2;
+	}
+
+	if ((num & 0x01) == 0x01) {
+		return 3;
+	}
+
+	return 0;
+}
+
+int BITRATES[3][5][16] = { {},
+	{
+		{},
+		{0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 0},
+		{0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 0},
+		{0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 0},
+		{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
+	},
+	{
+		{},
+		{0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0},
+		{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0},
+		{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0},
+		{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
+	}
+};
+
+int SAMPLE_RATES[3][4] = {
+	{0, 0, 0, 0},
+	{44100, 48000, 32000, 0},
+	{22050, 24000, 16000, 0}
+};
+
+int SAMPLES_PER_FRAME[3][4] = {
+	{0, 0, 0, 0},
+	{0, 384, 1152, 1152},
+	{0, 384, 1152, 576}
+};
+
+int getMpegFrameLength(bool has_padding, int sample_rate, uint8 layer, int bitrate, int num_samples) {
+
+	uint8 padding = has_padding ? 1 : 0;
+	if (sample_rate == 0) {
+		return 0;
+	}
+
+	if (layer == 1) {
+		return ((int) (12.0 * bitrate / sample_rate + padding)) * 4;
+	}
+
+	return ((int) (num_samples * (bitrate / 8) / sample_rate)) + padding;
+}
+
+uint8 getMpegChannels(uint8 num) {
+
+	/*
+	00 - Stereo
+	01 - Joint stereo (Stereo)
+	10 - Dual channel (2 mono channels)
+	11 - Single channel (Mono)
+	*/
+
+	if ((num & 0x03) == 0x03) {
+		return 1;
+	}
+
+	return 2;
+}
+
+int CheckFrameInfo(TArray<uint8> FileData, int i, int depth) {
+	bool isMP3 = (FileData[i] << 8 | (FileData[i + 1] & 0xF0)) == 0xFFF0;
+	if (!isMP3) return -1;
+
+	bool padding = (FileData[i + 2] & 0x02) >> 1 == 0x01;
+	uint8 mpegVersion = getMpegVersion(FileData[i + 1] >> 3);
+	uint8 mpegLayer = getMpegLayer(FileData[i + 1] >> 1);
+	int bitRate = BITRATES[mpegVersion][mpegLayer][(FileData[i + 2] >> 4) & 0x0F] * 1000;
+	int sampleRate = SAMPLE_RATES[mpegVersion][(FileData[i + 2] >> 2) & 0x03];
+	int sampleCount = SAMPLES_PER_FRAME[mpegVersion][mpegLayer];
+	uint8 channels = getMpegChannels(FileData[i + 3] >> 6);
+
+	int frameLength = getMpegFrameLength(padding, sampleRate, mpegLayer, bitRate, sampleCount);
+	if (frameLength == 0) return -1;
+
+	UE_LOG(LogTemp, Error, TEXT("Possible mp3 V: %d, L: %d, P: %d, Bitrate: %d, Channels: %d, Sample rate: %d, Sample count: %d, Frame len: %d"), mpegVersion, mpegLayer, padding, bitRate, channels, sampleRate, sampleCount, frameLength);
+
+	if (depth < 2) {
+		int otherBitrate = CheckFrameInfo(FileData, i + frameLength, depth + 1);
+		if (otherBitrate != bitRate) {
+			return -1;
+		}
+	}
+	return bitRate;
+}
+
+FString UBPFileIO::CheckAudioFormatMatches(const FString & TestPath)
+{
+	FString unknownProblem = "Error loading song file";
+
+	TArray<uint8> FileData;
+	if (!FFileHelper::LoadFileToArray(FileData, *TestPath))
+	{
+		UE_LOG(LogTemp, Error, TEXT("Failed to load file"));
+		return unknownProblem;
+	}
+
+	for (int i = 0; i < 1024; i++) {
+		if ((FileData[i] << 8 | (FileData[i+1] & 0xF0)) == 0xFFF0) {
+			if (CheckFrameInfo(FileData, i, 0) != -1) {
+				return "That looks like an MP3, you can't just rename files to change their type.\nGo get audacity and convert it properly.";
+			}
+
+			return unknownProblem;
+		}
+	}
+
+	return unknownProblem;
+}
+
 FString UBPFileIO::CheckImageFormatMatches(const FString & TestPath)
 {
 	FString unknownProblem = "Something's weird with your cover image, and i don't know what it is.";

Source/MediocreMapAssistant2/BPFileIO.h

@@ -23,6 +23,9 @@ class MEDIOCREMAPASSISTANT2_API UBPFileIO : public UBlueprintFunctionLibrary
 	UFUNCTION(BlueprintCallable, Category = "File IO")
 		static bool VerifyDirectory(const FString& TestDir);
 
+	UFUNCTION(BlueprintCallable, Category = "File IO")
+		static FString CheckAudioFormatMatches(const FString& TestPath);
+
 	UFUNCTION(BlueprintCallable, Category = "File IO")
 		static FString CheckImageFormatMatches(const FString& TestPath);