--- a
+++ b/mpd2src/flacencoder.cpp
@@ -0,0 +1,154 @@
+/* Copyright (C) 2015-2018 J.F.Dockes
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the
+ *   Free Software Foundation, Inc.,
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#include "flacencoder.h"
+#include "audioutil.h"
+#include "log.h"
+
+#include <string.h>
+
+#ifdef DEBUG_ENCODER
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+
+using namespace std;
+
+FlacEncoder::FlacEncoder(AudioReader* audioReader, OhmSenderDriver *ohmSender)
+    : AudioEncoder(audioReader, ohmSender, true, "FLAC")
+{
+    LOGDEB("New FLAC encoder\n");
+
+    m_encoder = FLAC__stream_encoder_new();
+    if (m_encoder == nullptr)
+        LOGERR("FlacEncoder: Failed to construct stream encoder\n");
+
+    FLAC__bool ok = true;
+    ok &= FLAC__stream_encoder_set_compression_level(m_encoder, 0);
+    ok &= FLAC__stream_encoder_set_channels(m_encoder,
+                                            m_audioReader->numChannels());
+    ok &= FLAC__stream_encoder_set_bits_per_sample(m_encoder,
+                                            m_audioReader->bitsPerSample());
+    ok &= FLAC__stream_encoder_set_sample_rate(m_encoder,
+                                            m_audioReader->sampleRate());
+    if (!ok)
+        LOGERR("FlacEncoder: Failed to set parameters for stream encoder\n");
+
+#ifdef DEBUG_ENCODER
+    dumpfd = open("/tmp/mpd2dump.flac", O_WRONLY|O_CREAT|O_TRUNC, 0666);
+#endif
+}
+
+FlacEncoder::~FlacEncoder()
+{
+    LOGDEB("Delete FLAC encoder\n");
+
+    FLAC__stream_encoder_delete(m_encoder);
+
+#ifdef DEBUG_ENCODER
+    if (dumpfd > 0)
+        close(dumpfd);
+#endif
+}
+
+void FlacEncoder::start()
+{
+    LOGDEB("Start FLAC encoder\n");
+
+    FLAC__StreamEncoderInitStatus init_status;
+    init_status = FLAC__stream_encoder_init_stream(m_encoder,
+                    writeCallback, nullptr, nullptr, nullptr, this);
+    if (init_status != FLAC__STREAM_ENCODER_INIT_STATUS_OK)
+        LOGERR("FlacEncoder: Failed to init stream for stream encoder: "
+                    << string(FLAC__StreamEncoderInitStatusString[init_status])
+                    << endl);
+}
+
+int FlacEncoder::encode(const unsigned char *buffer, unsigned num_bytes,
+                        bool halt)
+{
+    if (num_bytes == 0) {
+        LOGDEB("FlacEncoder: Sending an empty audio message with halt="
+                << halt << endl);
+        m_ohmSender->SendAudio((const TByte*)buffer, 0, halt, 0);
+        return 0;
+    }
+
+    m_halt = halt;
+
+    unsigned samples_left = num_bytes / 2; // each sample takes 2 bytes
+                                           // (16 bits per sample)
+    while (samples_left > 0) {
+        unsigned samples = samples_left > SAMPLES_BUF_SIZE ? SAMPLES_BUF_SIZE
+                                                           : samples_left;
+
+        // convert the packed little-endian 16-bit PCM samples into an
+        // interleaved FLAC__int32 buffer for libFLAC
+        for (unsigned i = 0; i < samples; i++) {
+            // inefficient but simple and works on big- or little-endian
+            // machines.
+            m_samplesBuf[i] = (FLAC__int32)
+                            (((FLAC__int16)(FLAC__int8)buffer[2*i+1] << 8)
+                            | (FLAC__int16)buffer[2*i]);
+        }
+
+        // feed samples to encoder
+        if (!FLAC__stream_encoder_process_interleaved(m_encoder, m_samplesBuf,
+                                                      samples / 2)) {
+            return 0;
+        }
+
+        samples_left -= samples;
+        buffer += samples * 2; // skip processed samples
+    }
+
+    return num_bytes; // consumed everything
+}
+
+void FlacEncoder::finish()
+{
+    LOGDEB("Finish FLAC encoder\n");
+
+    FLAC__stream_encoder_finish(m_encoder);
+}
+
+FLAC__StreamEncoderWriteStatus FlacEncoder::writeCallback(
+        const FLAC__StreamEncoder *encoder,
+        const FLAC__byte buffer[],  // An array of encoded data.
+        size_t bytes,               // The byte length of buffer.
+        unsigned samples,           // The number of samples encoded by buffer
+                                    // 0 has a special meaning.
+        unsigned current_frame,     // The number of the current frame being
+                                    // encoded.
+        void *client_data)
+{
+    FlacEncoder *enc = reinterpret_cast<FlacEncoder*>(client_data);
+
+    //LOGDEB("writeCallback: " << bytes << ", " << samples << ", "
+    //        << current_frame << ", " << enc->m_halt << endl);
+
+    if (samples > 0)
+        enc->m_ohmSender->SendAudio(buffer, bytes, enc->m_halt, samples);
+
+#ifdef DEBUG_ENCODER
+    if (enc->dumpfd > 0)
+        write(enc->dumpfd, buffer, bytes);
+#endif
+
+    return FLAC__STREAM_ENCODER_WRITE_STATUS_OK;
+}