From 97f61bb40c33640ab2de045ae540d641cd228620 Mon Sep 17 00:00:00 2001
From: "m.podoprelov" <zomb1pod@gmail.com>
Date: Mon, 13 Nov 2023 20:01:38 +0300
Subject: [PATCH] Add check and normalization for more than 16 bits per sample
 FLAC-files

---
 src/flactomp3.cpp | 22 +++++++++++++++++-----
 src/flactomp3.h   |  3 ++-
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/flactomp3.cpp b/src/flactomp3.cpp
index 2f7d67c..bb9b27b 100644
--- a/src/flactomp3.cpp
+++ b/src/flactomp3.cpp
@@ -294,16 +294,28 @@ bool FLACtoMP3::scaleJPEG(const FLAC__StreamMetadata_Picture& picture) {
     return true;
 }
 
-bool FLACtoMP3::decodeFrame(const int32_t * const buffer[], uint32_t size) {
+bool FLACtoMP3::decodeFrame(const int32_t * const buffer[], uint32_t size, const uint32_t bitsPerSample) {
     if (!outputInitilized) {
         bool success = initializeOutput();
         if (!success)
             return false;
     }
 
+    if (bitsPerSample >= 16)
+        return decodeFrameImpl(buffer, size, 1 << (bitsPerSample - 16));
+
+    return false;
+}
+
+bool FLACtoMP3::decodeFrameImpl(const int32_t * const buffer[], uint32_t size, const uint32_t divisor)
+{
     for (size_t i = 0; i < size; ++i) {
-        pcm[pcmCounter++] = (int16_t)buffer[0][i];
-        pcm[pcmCounter++] = (int16_t)buffer[1][i];
+        int32_t left = buffer[0][i];
+        int32_t right = buffer[1][i];
+        left /= divisor;
+        right /= divisor;
+        pcm[pcmCounter++] = (int16_t)left;
+        pcm[pcmCounter++] = (int16_t)right;
 
         if (pcmCounter == pcmSize)
             return flush();
@@ -394,8 +406,8 @@ FLAC__StreamDecoderWriteStatus FLACtoMP3::write(
         self->logger.fatal("ERROR: buffer [1] is NULL");
         return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
     }
-
-    bool result = self->decodeFrame(buffer, frame->header.blocksize);
+    
+    bool result = self->decodeFrame(buffer, frame->header.blocksize, frame->header.bits_per_sample);
 
     if (result)
         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
diff --git a/src/flactomp3.h b/src/flactomp3.h
index 0bf1a8a..d246b5a 100644
--- a/src/flactomp3.h
+++ b/src/flactomp3.h
@@ -29,7 +29,8 @@ private:
     void processTags(const FLAC__StreamMetadata_VorbisComment& tags);
     void processInfo(const FLAC__StreamMetadata_StreamInfo& info);
     void processPicture(const FLAC__StreamMetadata_Picture& picture);
-    bool decodeFrame(const int32_t * const buffer[], uint32_t size);
+    bool decodeFrame(const int32_t * const buffer[], uint32_t size, const uint32_t bitsPerSample);
+    bool decodeFrameImpl(const int32_t * const buffer[], uint32_t size, const uint32_t divisor);
     bool flush();
     bool initializeOutput();
     bool scaleJPEG(const FLAC__StreamMetadata_Picture& picture);