diff --git a/src/coding/coding.h b/src/coding/coding.h
index 9911d3cb..5f23599c 100644
--- a/src/coding/coding.h
+++ b/src/coding/coding.h
@@ -207,6 +207,9 @@ typedef struct {
 void xma_get_samples(xma_sample_data * msd, STREAMFILE *streamFile);
 void wmapro_get_samples(xma_sample_data * msd, STREAMFILE *streamFile, int block_align, int sample_rate, uint32_t decode_flags);
 
+size_t atrac3_bytes_to_samples(size_t bytes, int full_block_align);
+size_t atrac3plus_bytes_to_samples(size_t bytes, int full_block_align);
+
 #endif
 
 #endif /*_CODING_H*/
diff --git a/src/coding/ffmpeg_decoder_utils.c b/src/coding/ffmpeg_decoder_utils.c
index 83598e6c..13bbde36 100644
--- a/src/coding/ffmpeg_decoder_utils.c
+++ b/src/coding/ffmpeg_decoder_utils.c
@@ -631,4 +631,16 @@ void wmapro_get_samples(xma_sample_data * msd, STREAMFILE *streamFile, int block
 }
 
 
+size_t atrac3_bytes_to_samples(size_t bytes, int full_block_align) {
+    /* ATRAC3 expects full block align since as is can mix joint stereo with mono blocks;
+     * so (full_block_align / channels) DOESN'T give the size of a single channel (uncommon in ATRAC3 though) */
+    return (bytes / full_block_align) * 1024;
+}
+
+size_t atrac3plus_bytes_to_samples(size_t bytes, int full_block_align) {
+    /* ATRAC3plus expects full block align since as is can mix joint stereo with mono blocks;
+     * so (full_block_align / channels) DOESN'T give the size of a single channel (common in ATRAC3plus) */
+    return (bytes / full_block_align) * 2048;
+}
+
 #endif
diff --git a/src/meta/gsp_gsb.c b/src/meta/gsp_gsb.c
index 549707b8..17b636fc 100644
--- a/src/meta/gsp_gsb.c
+++ b/src/meta/gsp_gsb.c
@@ -82,9 +82,9 @@ VGMSTREAM * init_vgmstream_gsp_gsb(STREAMFILE *streamFile) {
             uint8_t buf[100];
             int32_t bytes, block_size, encoder_delay, joint_stereo, max_samples;
 
-            block_size = 0x98 * vgmstream->channels;
-            joint_stereo = 0;
-            max_samples = (datasize / block_size) * 1024;
+            block_size    = 0x98 * vgmstream->channels;
+            joint_stereo  = 0;
+            max_samples   = atrac3_bytes_to_samples(datasize, block_size);;
             encoder_delay = max_samples - vgmstream->num_samples; /* todo guessed */
 
             vgmstream->num_samples += encoder_delay;
diff --git a/src/meta/ps3_msf.c b/src/meta/ps3_msf.c
index 5a5ceb2e..226f07e7 100644
--- a/src/meta/ps3_msf.c
+++ b/src/meta/ps3_msf.c
@@ -104,12 +104,12 @@ VGMSTREAM * init_vgmstream_ps3_msf(STREAMFILE *streamFile) {
         case 0x6: { /* ATRAC3 high (132 kbps, frame size 192) */
             ffmpeg_codec_data *ffmpeg_data = NULL;
             uint8_t buf[100];
-            int32_t bytes, samples_size = 1024, block_size, encoder_delay, joint_stereo, max_samples;
+            int32_t bytes, block_size, encoder_delay, joint_stereo, max_samples;
 
-            block_size = (codec_id==4 ? 0x60 : (codec_id==5 ? 0x98 : 0xC0)) * vgmstream->channels;
+            block_size    = (codec_id==4 ? 0x60 : (codec_id==5 ? 0x98 : 0xC0)) * vgmstream->channels;
             encoder_delay = 0x0; //todo MSF encoder delay (around 440-450*2)
-            max_samples = (data_size / block_size) * samples_size;
-            joint_stereo = codec_id==4; /* interleaved joint stereo (ch must be even) */
+            max_samples   = atrac3_bytes_to_samples(data_size, block_size);
+            joint_stereo  = codec_id==4; /* interleaved joint stereo (ch must be even) */
 
             if (vgmstream->sample_rate==0xFFFFFFFF) /* some MSFv1 (Digi World SP) */
                 vgmstream->sample_rate = 44100;//voice tracks seems to use 44khz, not sure about other tracks
@@ -126,8 +126,8 @@ VGMSTREAM * init_vgmstream_ps3_msf(STREAMFILE *streamFile) {
 
             vgmstream->num_samples = max_samples;
             if (loop_flag) {
-                vgmstream->loop_start_sample = (loop_start / block_size) * samples_size;
-                vgmstream->loop_end_sample = (loop_end / block_size) * samples_size;
+                vgmstream->loop_start_sample = atrac3_bytes_to_samples(loop_start, block_size);
+                vgmstream->loop_end_sample   = atrac3_bytes_to_samples(loop_end, block_size);
             }
 
             break;
diff --git a/src/meta/xwb.c b/src/meta/xwb.c
index 105111a8..7bf5c963 100644
--- a/src/meta/xwb.c
+++ b/src/meta/xwb.c
@@ -226,7 +226,7 @@ VGMSTREAM * init_vgmstream_xwb(STREAMFILE *streamFile) {
 
         /* num samples uses a modified entry_info format (maybe skip samples + samples? sfx use the standard format)
          * ignore for now and just calc max samples */ //todo
-        xwb.num_samples = xwb.stream_size / (xwb.block_align * xwb.channels) * 1024;
+        xwb.num_samples = atrac3_bytes_to_samples(xwb.stream_size, xwb.block_align * xwb.channels);
     }