EncoderMP3: Fix conversion warnings on Windows

Fixes:

    src\encoder\encodermp3.cpp(122): warning C4267: '=': conversion from 'size_t' to 'int', possible loss of data
    src\encoder\encodermp3.cpp(125): warning C4267: '=': conversion from 'size_t' to 'int', possible loss of data

1 files changed, 9 insertions, 6 deletions

diff --git a/src/encoder/encodermp3.cpp b/src/encoder/encodermp3.cpp
index f938bb3411..d8053ea27d 100644
--- a/src/encoder/encodermp3.cpp
+++ b/src/encoder/encodermp3.cpp
@@ -118,14 +118,17 @@ void EncoderMp3::flush() {
     // end encoded audio to broadcast or file
     m_pCallback->write(nullptr, m_bufferOut, 0, rc);
 
-    // Write the lame/xing header.
-    rc = lame_get_lametag_frame(m_lameFlags, m_bufferOut, m_bufferOutSize);
-    if (rc != m_bufferOutSize) {
-        bufferOutGrow(rc);
-        rc = lame_get_lametag_frame(m_lameFlags, m_bufferOut, m_bufferOutSize);
+    // `lame_get_lametag_frame` returns the number of bytes copied into buffer,
+    // or the required buffer size, if the provided buffer is too small.
+    // Function failed, if the return value is larger than `m_bufferOutSize`!
+    size_t numBytes = lame_get_lametag_frame(m_lameFlags, m_bufferOut, m_bufferOutSize);
+    if (numBytes > static_cast<size_t>(m_bufferOutSize)) {
+        bufferOutGrow(numBytes);
+        numBytes = lame_get_lametag_frame(m_lameFlags, m_bufferOut, m_bufferOutSize);
     }
+    // Write the lame/xing header.
     m_pCallback->seek(0);
-    m_pCallback->write(nullptr, m_bufferOut, 0, rc);
+    m_pCallback->write(nullptr, m_bufferOut, 0, static_cast<int>(numBytes));
 }
 
 void EncoderMp3::encodeBuffer(const CSAMPLE *samples, const int size) {