fixed multichannel decoding in sndfile plugin

1 files changed, 44 insertions, 10 deletions

diff --git a/plugins/sndfile/sndfile.c b/plugins/sndfile/sndfile.c
index 0cb48675..90390603 100644
--- a/plugins/sndfile/sndfile.c
+++ b/plugins/sndfile/sndfile.c
@@ -174,16 +174,34 @@ sndfile_free (DB_fileinfo_t *_info) {
 static int
 sndfile_read_int16 (DB_fileinfo_t *_info, char *bytes, int size) {
     sndfile_info_t *info = (sndfile_info_t*)_info;
-    if (size / (2 * _info->channels) + info->currentsample > info->endsample) {
-        size = (info->endsample - info->currentsample + 1) * 2 * _info->channels;
-        trace ("wv: size truncated to %d bytes, cursample=%d, endsample=%d\n", size, info->currentsample, info->endsample);
+    int out_ch = min (_info->channels, 2);
+    if (size / (2 * out_ch) + info->currentsample > info->endsample) {
+        size = (info->endsample - info->currentsample + 1) * 2 * out_ch;
+        trace ("sndfile: size truncated to %d bytes, cursample=%d, endsample=%d\n", size, info->currentsample, info->endsample);
         if (size <= 0) {
             return 0;
         }
     }
-    int n = sf_readf_short (info->ctx, (short *)bytes, size/(2*_info->channels));
+
+    int n = 0;
+    if (out_ch != _info->channels) {
+        // read into temp buffer, and downmix
+        int nframes = size / out_ch / 2;
+        int16_t buf[nframes * _info->channels];
+        n = sf_readf_short (info->ctx, buf, nframes);
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < out_ch; j++) {
+                ((int16_t *)bytes)[i * out_ch + j] = buf[i * _info->channels + j];
+            }
+        }
+    }
+    else {
+        n = sf_readf_short (info->ctx, (short *)bytes, size/(2*_info->channels));
+    }
     info->currentsample += n;
-    size = n * 2 * _info->channels;
+
+
+    size = n * 2 * out_ch;
     _info->readpos = (float)(info->currentsample-info->startsample)/_info->samplerate;
     if (info->bitrate > 0) {
         deadbeef->streamer_set_bitrate (info->bitrate);
@@ -194,16 +212,32 @@ sndfile_read_int16 (DB_fileinfo_t *_info, char *bytes, int size) {
 static int
 sndfile_read_float32 (DB_fileinfo_t *_info, char *bytes, int size) {
     sndfile_info_t *info = (sndfile_info_t*)_info;
-    if (size / (4 * _info->channels) + info->currentsample > info->endsample) {
-        size = (info->endsample - info->currentsample + 1) * 4 * _info->channels;
-        trace ("wv: size truncated to %d bytes, cursample=%d, endsample=%d\n", size, info->currentsample, info->endsample);
+    int out_ch = min (_info->channels, 2);
+    if (size / (4 * out_ch) + info->currentsample > info->endsample) {
+        size = (info->endsample - info->currentsample + 1) * 4 * out_ch;
+        trace ("sndfile: size truncated to %d bytes, cursample=%d, endsample=%d\n", size, info->currentsample, info->endsample);
         if (size <= 0) {
             return 0;
         }
     }
-    int n = sf_readf_float (info->ctx, (float *)bytes, size/(4*_info->channels));
+    int n = 0;
+    if (out_ch != _info->channels) {
+        // read into temp buffer, and downmix
+        int nframes = size / out_ch / 4;
+        float buf[nframes * _info->channels];
+        n = sf_readf_float (info->ctx, buf, nframes);
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < out_ch; j++) {
+                ((float *)bytes)[i * out_ch + j] = buf[i * _info->channels + j];
+            }
+        }
+    }
+    else {
+        n = sf_readf_float (info->ctx, (float *)bytes, size/(4*_info->channels));
+    }
+
     info->currentsample += n;
-    size = n * 4 * _info->channels;
+    size = n * 4 * out_ch;
     _info->readpos = (float)(info->currentsample-info->startsample)/_info->samplerate;
     if (info->bitrate > 0) {
         deadbeef->streamer_set_bitrate (info->bitrate);