diff --git a/src/base/mixing.c b/src/base/mixing.c
index 85237f1d..84b354c6 100644
--- a/src/base/mixing.c
+++ b/src/base/mixing.c
@@ -103,10 +103,10 @@ void mix_vgmstream(sample_t *outbuf, int32_t sample_count, VGMSTREAM* vgmstream)
      */
     data->current_channels = vgmstream->channels;
     for (int m = 0; m < data->mixing_count; m++) {
-        mix_command_data* mix = &data->mixing_chain[m];
+        mix_op_t* mix = &data->mixing_chain[m];
 
         //TODO: set callback
-        switch(mix->command) {
+        switch(mix->type) {
             case MIX_SWAP:      mixer_op_swap(data, sample_count, mix); break;
             case MIX_ADD:       mixer_op_add(data, sample_count, mix); break;
             case MIX_VOLUME:    mixer_op_volume(data, sample_count, mix); break;
@@ -166,7 +166,6 @@ void mixing_update_channel(VGMSTREAM* vgmstream) {
 /* ******************************************************************* */
 
 static int fix_layered_channel_layout(VGMSTREAM* vgmstream) {
-    int i;
     mixer_data_t* data = vgmstream->mixing_data;
     layered_layout_data* layout_data;
     uint32_t prev_cl;
@@ -185,7 +184,7 @@ static int fix_layered_channel_layout(VGMSTREAM* vgmstream) {
     if (prev_cl == 0)
         return 0;
 
-    for (i = 1; i < layout_data->layer_count; i++) {
+    for (int i = 1; i < layout_data->layer_count; i++) {
         uint32_t layer_cl = layout_data->layers[i]->channel_layout;
         if (prev_cl != layer_cl)
             return 0;
diff --git a/src/base/mixing_commands.c b/src/base/mixing_commands.c
index 8fb87c90..0ef39617 100644
--- a/src/base/mixing_commands.c
+++ b/src/base/mixing_commands.c
@@ -5,7 +5,7 @@
 #include <limits.h>
 
 
-static bool add_mixing(VGMSTREAM* vgmstream, mix_command_data *mix) {
+static bool add_mixing(VGMSTREAM* vgmstream, mix_op_t* op) {
     mixer_data_t* data = vgmstream->mixing_data;
     if (!data)
         return false;
@@ -21,11 +21,11 @@ static bool add_mixing(VGMSTREAM* vgmstream, mix_command_data *mix) {
         return false;
     }
 
-    data->mixing_chain[data->mixing_count] = *mix; /* memcpy */
+    data->mixing_chain[data->mixing_count] = *op; /* memcpy */
     data->mixing_count++;
 
 
-    if (mix->command == MIX_FADE) {
+    if (op->type == MIX_FADE) {
         data->has_fade = true;
     }
     else {
@@ -39,20 +39,20 @@ static bool add_mixing(VGMSTREAM* vgmstream, mix_command_data *mix) {
 
 void mixing_push_swap(VGMSTREAM* vgmstream, int ch_dst, int ch_src) {
     mixer_data_t* data = vgmstream->mixing_data;
-    mix_command_data mix = {0};
+    mix_op_t op = {0};
 
     if (ch_dst < 0 || ch_src < 0 || ch_dst == ch_src) return;
     if (!data || ch_dst >= data->output_channels || ch_src >= data->output_channels) return;
-    mix.command = MIX_SWAP;
-    mix.ch_dst = ch_dst;
-    mix.ch_src = ch_src;
+    op.type = MIX_SWAP;
+    op.ch_dst = ch_dst;
+    op.ch_src = ch_src;
 
-    add_mixing(vgmstream, &mix);
+    add_mixing(vgmstream, &op);
 }
 
 void mixing_push_add(VGMSTREAM* vgmstream, int ch_dst, int ch_src, double volume) {
     mixer_data_t* data = vgmstream->mixing_data;
-    mix_command_data mix = {0};
+    mix_op_t op = {0};
     if (!data) return;
 
     //if (volume < 0.0) return; /* negative volume inverts the waveform */
@@ -60,35 +60,35 @@ void mixing_push_add(VGMSTREAM* vgmstream, int ch_dst, int ch_src, double volume
     if (ch_dst < 0 || ch_src < 0) return;
     if (!data || ch_dst >= data->output_channels || ch_src >= data->output_channels) return;
 
-    mix.command = MIX_ADD;
-    mix.ch_dst = ch_dst;
-    mix.ch_src = ch_src;
-    mix.vol = volume;
+    op.type = MIX_ADD;
+    op.ch_dst = ch_dst;
+    op.ch_src = ch_src;
+    op.vol = volume;
 
     //;VGM_LOG("MIX: add %i+%i*%f\n", ch_dst,ch_src,volume);
-    add_mixing(vgmstream, &mix);
+    add_mixing(vgmstream, &op);
 }
 
 void mixing_push_volume(VGMSTREAM* vgmstream, int ch_dst, double volume) {
     mixer_data_t* data = vgmstream->mixing_data;
-    mix_command_data mix = {0};
+    mix_op_t op = {0};
 
     //if (ch_dst < 0) return; /* means all channels */
     //if (volume < 0.0) return; /* negative volume inverts the waveform */
     if (volume == 1.0) return; /* no change */
     if (!data || ch_dst >= data->output_channels) return;
 
-    mix.command = MIX_VOLUME; //if (volume == 0.0) MIX_VOLUME0 /* could simplify */
-    mix.ch_dst = ch_dst;
-    mix.vol = volume;
+    op.type = MIX_VOLUME; //if (volume == 0.0) MIX_VOLUME0 /* could simplify */
+    op.ch_dst = ch_dst;
+    op.vol = volume;
 
     //;VGM_LOG("MIX: volume %i*%f\n", ch_dst,volume);
-    add_mixing(vgmstream, &mix);
+    add_mixing(vgmstream, &op);
 }
 
 void mixing_push_limit(VGMSTREAM* vgmstream, int ch_dst, double volume) {
     mixer_data_t* data = vgmstream->mixing_data;
-    mix_command_data mix = {0};
+    mix_op_t op = {0};
 
     //if (ch_dst < 0) return; /* means all channels */
     if (volume < 0.0) return;
@@ -96,26 +96,26 @@ void mixing_push_limit(VGMSTREAM* vgmstream, int ch_dst, double volume) {
     if (!data || ch_dst >= data->output_channels) return;
     //if (volume == 0.0) return; /* dumb but whatevs */
 
-    mix.command = MIX_LIMIT;
-    mix.ch_dst = ch_dst;
-    mix.vol = volume;
+    op.type = MIX_LIMIT;
+    op.ch_dst = ch_dst;
+    op.vol = volume;
 
-    add_mixing(vgmstream, &mix);
+    add_mixing(vgmstream, &op);
 }
 
 void mixing_push_upmix(VGMSTREAM* vgmstream, int ch_dst) {
     mixer_data_t* data = vgmstream->mixing_data;
-    mix_command_data mix = {0};
+    mix_op_t op = {0};
     int ok;
 
     if (ch_dst < 0) return;
     if (!data || ch_dst > data->output_channels || data->output_channels +1 > VGMSTREAM_MAX_CHANNELS) return;
     /* dst can be == output_channels here, since we are inserting */
 
-    mix.command = MIX_UPMIX;
-    mix.ch_dst = ch_dst;
+    op.type = MIX_UPMIX;
+    op.ch_dst = ch_dst;
 
-    ok = add_mixing(vgmstream, &mix);
+    ok = add_mixing(vgmstream, &op);
     if (ok) {
         data->output_channels += 1;
         if (data->mixing_channels < data->output_channels)
@@ -125,16 +125,16 @@ void mixing_push_upmix(VGMSTREAM* vgmstream, int ch_dst) {
 
 void mixing_push_downmix(VGMSTREAM* vgmstream, int ch_dst) {
     mixer_data_t* data = vgmstream->mixing_data;
-    mix_command_data mix = {0};
+    mix_op_t op = {0};
     int ok;
 
     if (ch_dst < 0) return;
     if (!data || ch_dst >= data->output_channels || data->output_channels - 1 < 1) return;
 
-    mix.command = MIX_DOWNMIX;
-    mix.ch_dst = ch_dst;
+    op.type = MIX_DOWNMIX;
+    op.ch_dst = ch_dst;
 
-    ok = add_mixing(vgmstream, &mix);
+    ok = add_mixing(vgmstream, &op);
     if (ok) {
         data->output_channels -= 1;
     }
@@ -142,31 +142,29 @@ void mixing_push_downmix(VGMSTREAM* vgmstream, int ch_dst) {
 
 void mixing_push_killmix(VGMSTREAM* vgmstream, int ch_dst) {
     mixer_data_t* data = vgmstream->mixing_data;
-    mix_command_data mix = {0};
-    int ok;
+    mix_op_t op = {0};
 
     if (ch_dst <= 0) return; /* can't kill from first channel */
     if (!data || ch_dst >= data->output_channels) return;
 
-    mix.command = MIX_KILLMIX;
-    mix.ch_dst = ch_dst;
+    op.type = MIX_KILLMIX;
+    op.ch_dst = ch_dst;
 
     //;VGM_LOG("MIX: killmix %i\n", ch_dst);
-    ok = add_mixing(vgmstream, &mix);
+    bool ok = add_mixing(vgmstream, &op);
     if (ok) {
         data->output_channels = ch_dst; /* clamp channels */
     }
 }
 
 
-static mix_command_data* get_last_fade(mixer_data_t* data, int target_channel) {
-    int i;
-    for (i = data->mixing_count; i > 0; i--) {
-        mix_command_data *mix = &data->mixing_chain[i-1];
-        if (mix->command != MIX_FADE)
+static mix_op_t* get_last_fade(mixer_data_t* data, int target_channel) {
+    for (int i = data->mixing_count; i > 0; i--) {
+        mix_op_t* op = &data->mixing_chain[i-1];
+        if (op->type != MIX_FADE)
             continue;
-        if (mix->ch_dst == target_channel)
-            return mix;
+        if (op->ch_dst == target_channel)
+            return op;
     }
 
     return NULL;
@@ -176,8 +174,8 @@ static mix_command_data* get_last_fade(mixer_data_t* data, int target_channel) {
 void mixing_push_fade(VGMSTREAM* vgmstream, int ch_dst, double vol_start, double vol_end, char shape,
         int32_t time_pre, int32_t time_start, int32_t time_end, int32_t time_post) {
     mixer_data_t* data = vgmstream->mixing_data;
-    mix_command_data mix = {0};
-    mix_command_data *mix_prev;
+    mix_op_t op = {0};
+    mix_op_t* op_prev;
 
 
     //if (ch_dst < 0) return; /* means all channels */
@@ -192,15 +190,15 @@ void mixing_push_fade(VGMSTREAM* vgmstream, int ch_dst, double vol_start, double
     if (shape == '(' || shape == ')')
         shape = 'H';
 
-    mix.command = MIX_FADE;
-    mix.ch_dst = ch_dst;
-    mix.vol_start = vol_start;
-    mix.vol_end = vol_end;
-    mix.shape = shape;
-    mix.time_pre = time_pre;
-    mix.time_start = time_start;
-    mix.time_end = time_end;
-    mix.time_post = time_post;
+    op.type = MIX_FADE;
+    op.ch_dst = ch_dst;
+    op.vol_start = vol_start;
+    op.vol_end = vol_end;
+    op.shape = shape;
+    op.time_pre = time_pre;
+    op.time_start = time_start;
+    op.time_end = time_end;
+    op.time_post = time_post;
 
 
     /* cancel fades and optimize a bit when using negative pre/post:
@@ -216,33 +214,33 @@ void mixing_push_fade(VGMSTREAM* vgmstream, int ch_dst, double vol_start, double
      *   as they're uncommon and hard to optimize
      * fades cancel fades of the same channel, and 'all channel' (-1) fades also cancel 'all channels'
      */
-    mix_prev = get_last_fade(data, mix.ch_dst);
-    if (mix_prev == NULL) {
+    op_prev = get_last_fade(data, op.ch_dst);
+    if (op_prev == NULL) {
         if (vol_start == 1.0 && time_pre < 0)
             time_pre = time_start; /* fade-out helds default volume before fade start can be clamped */
         if (vol_end == 1.0 && time_post < 0)
             time_post = time_end; /* fade-in helds default volume after fade end can be clamped */
     }
-    else if (mix_prev->time_post < 0 || mix.time_pre < 0) {
+    else if (op_prev->time_post < 0 || op.time_pre < 0) {
         int is_prev = 1;
         /* test if prev is really cancelled by this */
-        if ((mix_prev->time_end > mix.time_start) ||
-            (mix_prev->time_post >= 0 && mix_prev->time_post > mix.time_start) ||
-            (mix.time_pre >= 0 && mix.time_pre < mix_prev->time_end))
+        if ((op_prev->time_end > op.time_start) ||
+            (op_prev->time_post >= 0 && op_prev->time_post > op.time_start) ||
+            (op.time_pre >= 0 && op.time_pre < op_prev->time_end))
             is_prev = 0;
 
         if (is_prev) {
             /* change negative values to actual points */
-            if (mix_prev->time_post < 0 && mix.time_pre < 0) {
-                mix_prev->time_post = mix_prev->time_end;
-                mix.time_pre = mix_prev->time_post;
+            if (op_prev->time_post < 0 && op.time_pre < 0) {
+                op_prev->time_post = op_prev->time_end;
+                op.time_pre = op_prev->time_post;
             }
 
-            if (mix_prev->time_post >= 0 && mix.time_pre < 0) {
-                mix.time_pre = mix_prev->time_post;
+            if (op_prev->time_post >= 0 && op.time_pre < 0) {
+                op.time_pre = op_prev->time_post;
             }
-            else if (mix_prev->time_post < 0 && mix.time_pre >= 0) {
-                mix_prev->time_post = mix.time_pre;
+            else if (op_prev->time_post < 0 && op.time_pre >= 0) {
+                op_prev->time_post = op.time_pre;
             }
             /* else: both define start/ends, do nothing */
         }
@@ -250,5 +248,5 @@ void mixing_push_fade(VGMSTREAM* vgmstream, int ch_dst, double vol_start, double
     }
 
     //;VGM_LOG("MIX: fade %i^%f~%f=%c@%i~%i~%i~%i\n", ch_dst, vol_start, vol_end, shape, time_pre, time_start, time_end, time_post);
-    add_mixing(vgmstream, &mix);
+    add_mixing(vgmstream, &op);
 }
diff --git a/src/base/mixing_macros.c b/src/base/mixing_macros.c
index 7beb28b1..dc00e0f5 100644
--- a/src/base/mixing_macros.c
+++ b/src/base/mixing_macros.c
@@ -76,8 +76,8 @@ static int is_layered_auto(VGMSTREAM* vgmstream, int max, char mode) {
     /* no channel down/upmixing (cannot guess output) */
     mixer_data_t* data = vgmstream->mixing_data;
     for (int i = 0; i < data->mixing_count; i++) {
-        mix_command_t mix = data->mixing_chain[i].command;
-        if (mix == MIX_UPMIX || mix == MIX_DOWNMIX || mix == MIX_KILLMIX) /*mix == MIX_SWAP || ??? */
+        mix_type_t type = data->mixing_chain[i].type;
+        if (type == MIX_UPMIX || type == MIX_DOWNMIX || type == MIX_KILLMIX) /*type == MIX_SWAP || ??? */
             return 0;
     }
 
diff --git a/src/base/mixing_ops_common.c b/src/base/mixing_ops_common.c
index 43f6b33c..e4f4ff84 100644
--- a/src/base/mixing_ops_common.c
+++ b/src/base/mixing_ops_common.c
@@ -5,60 +5,60 @@
 // when there are no actual float ops (ex. 'swap', if no ' volume' )
 // Performance gain is probably fairly small, though.
 
-void mixer_op_swap(mixer_data_t* data, int32_t sample_count, mix_command_data* mix) {
+void mixer_op_swap(mixer_data_t* data, int32_t sample_count, mix_op_t* op) {
     float* sbuf = data->mixbuf;
 
     for (int s = 0; s < sample_count; s++) {
-        float temp_f = sbuf[mix->ch_dst];
-        sbuf[mix->ch_dst] = sbuf[mix->ch_src];
-        sbuf[mix->ch_src] = temp_f;
+        float temp_f = sbuf[op->ch_dst];
+        sbuf[op->ch_dst] = sbuf[op->ch_src];
+        sbuf[op->ch_src] = temp_f;
 
         sbuf += data->current_channels;
     }
 }
 
-void mixer_op_add(mixer_data_t* data, int32_t sample_count, mix_command_data* mix) {
+void mixer_op_add(mixer_data_t* data, int32_t sample_count, mix_op_t* op) {
     float* sbuf = data->mixbuf;
 
     /* could optimize when vol == 1 to avoid one multiplication but whatevs (not common) */
     for (int s = 0; s < sample_count; s++) {
-        sbuf[mix->ch_dst] = sbuf[mix->ch_dst] + sbuf[mix->ch_src] * mix->vol;
+        sbuf[op->ch_dst] = sbuf[op->ch_dst] + sbuf[op->ch_src] * op->vol;
 
         sbuf += data->current_channels;
     }
 }
 
-void mixer_op_volume(mixer_data_t* data, int32_t sample_count, mix_command_data* mix) {
+void mixer_op_volume(mixer_data_t* data, int32_t sample_count, mix_op_t* op) {
     float* sbuf = data->mixbuf;
     
-    if (mix->ch_dst < 0) {
+    if (op->ch_dst < 0) {
         /* "all channels", most common case */
         for (int s = 0; s < sample_count * data->current_channels; s++) {
-            sbuf[s] = sbuf[s] * mix->vol;
+            sbuf[s] = sbuf[s] * op->vol;
         }
     }
     else {
         for (int s = 0; s < sample_count; s++) {
-            sbuf[mix->ch_dst] = sbuf[mix->ch_dst] * mix->vol;
+            sbuf[op->ch_dst] = sbuf[op->ch_dst] * op->vol;
 
             sbuf += data->current_channels;
         }
     }
 }
 
-void mixer_op_limit(mixer_data_t* data, int32_t sample_count, mix_command_data* mix) {
+void mixer_op_limit(mixer_data_t* data, int32_t sample_count, mix_op_t* op) {
     float* sbuf = data->mixbuf;
 
     const float limiter_max = 32767.0f;
     const float limiter_min = -32768.0f;
 
-    const float temp_max = limiter_max * mix->vol;
-    const float temp_min = limiter_min * mix->vol;
+    const float temp_max = limiter_max * op->vol;
+    const float temp_min = limiter_min * op->vol;
 
     /* could optimize when vol == 1 to avoid one multiplication but whatevs (not common) */
     for (int s = 0; s < sample_count; s++) {
 
-        if (mix->ch_dst < 0) {
+        if (op->ch_dst < 0) {
             for (int ch = 0; ch < data->current_channels; ch++) {
                 if (sbuf[ch] > temp_max)
                     sbuf[ch] = temp_max;
@@ -67,17 +67,17 @@ void mixer_op_limit(mixer_data_t* data, int32_t sample_count, mix_command_data*
             }
         }
         else {
-            if (sbuf[mix->ch_dst] > temp_max)
-                sbuf[mix->ch_dst] = temp_max;
-            else if (sbuf[mix->ch_dst] < temp_min)
-                sbuf[mix->ch_dst] = temp_min;
+            if (sbuf[op->ch_dst] > temp_max)
+                sbuf[op->ch_dst] = temp_max;
+            else if (sbuf[op->ch_dst] < temp_min)
+                sbuf[op->ch_dst] = temp_min;
         }
 
         sbuf += data->current_channels;
     }
 }
 
-void mixer_op_upmix(mixer_data_t* data, int32_t sample_count, mix_command_data* mix) {
+void mixer_op_upmix(mixer_data_t* data, int32_t sample_count, mix_op_t* op) {
     int max_channels = data->current_channels;
     data->current_channels += 1;
 
@@ -91,7 +91,7 @@ void mixer_op_upmix(mixer_data_t* data, int32_t sample_count, mix_command_data*
 
         int sbuf_ch = max_channels - 1;
         for (int ch = data->current_channels - 1; ch >= 0; ch--) {
-            if (ch == mix->ch_dst) {
+            if (ch == op->ch_dst) {
                 sbuf_tmp[ch] = 0; /* inserted as silent */
             }
             else {
@@ -102,7 +102,7 @@ void mixer_op_upmix(mixer_data_t* data, int32_t sample_count, mix_command_data*
     }
 }
 
-void mixer_op_downmix(mixer_data_t* data, int32_t sample_count, mix_command_data* mix) {
+void mixer_op_downmix(mixer_data_t* data, int32_t sample_count, mix_op_t* op) {
     int max_channels = data->current_channels;
     data->current_channels -= 1;
 
@@ -111,11 +111,11 @@ void mixer_op_downmix(mixer_data_t* data, int32_t sample_count, mix_command_data
 
     for (int s = 0; s < sample_count; s++) {
 
-        for (int ch = 0; ch < mix->ch_dst; ch++) {
+        for (int ch = 0; ch < op->ch_dst; ch++) {
             sbuf_tmp[ch] = sbuf[ch]; /* copy untouched channels */
         }
 
-        for (int ch = mix->ch_dst; ch < max_channels; ch++) {
+        for (int ch = op->ch_dst; ch < max_channels; ch++) {
             sbuf_tmp[ch] = sbuf[ch + 1]; /* 'pull' dropped channels back */
         }
 
@@ -124,9 +124,9 @@ void mixer_op_downmix(mixer_data_t* data, int32_t sample_count, mix_command_data
     }
 }
 
-void mixer_op_killmix(mixer_data_t* data, int32_t sample_count, mix_command_data* mix) {
+void mixer_op_killmix(mixer_data_t* data, int32_t sample_count, mix_op_t* op) {
     int max_channels = data->current_channels;
-    data->current_channels = mix->ch_dst; /* clamp channels */
+    data->current_channels = op->ch_dst; /* clamp channels */
 
     float* sbuf = data->mixbuf;
     float* sbuf_tmp = sbuf;
diff --git a/src/base/mixing_ops_fade.c b/src/base/mixing_ops_fade.c
index 7945dba3..c4217766 100644
--- a/src/base/mixing_ops_fade.c
+++ b/src/base/mixing_ops_fade.c
@@ -54,28 +54,28 @@ static inline float get_fade_gain_curve(char shape, float index) {
     return gain;
 }
 
-static bool get_fade_gain(mix_command_data *mix, float *out_cur_vol, int32_t current_subpos) {
+static bool get_fade_gain(mix_op_t* op, float* out_cur_vol, int32_t current_subpos) {
     float cur_vol = 0.0f;
 
-    if ((current_subpos >= mix->time_pre || mix->time_pre < 0) && current_subpos < mix->time_start) {
-        cur_vol = mix->vol_start; /* before */
+    if ((current_subpos >= op->time_pre || op->time_pre < 0) && current_subpos < op->time_start) {
+        cur_vol = op->vol_start; /* before */
     }
-    else if (current_subpos >= mix->time_end && (current_subpos < mix->time_post || mix->time_post < 0)) {
-        cur_vol = mix->vol_end; /* after */
+    else if (current_subpos >= op->time_end && (current_subpos < op->time_post || op->time_post < 0)) {
+        cur_vol = op->vol_end; /* after */
     }
-    else if (current_subpos >= mix->time_start && current_subpos < mix->time_end) {
+    else if (current_subpos >= op->time_start && current_subpos < op->time_end) {
         /* in between */
         float range_vol, range_dur, range_idx, index, gain;
 
-        if (mix->vol_start < mix->vol_end) { /* fade in */
-            range_vol = mix->vol_end - mix->vol_start;
-            range_dur = mix->time_end - mix->time_start;
-            range_idx = current_subpos - mix->time_start;
+        if (op->vol_start < op->vol_end) { /* fade in */
+            range_vol = op->vol_end - op->vol_start;
+            range_dur = op->time_end - op->time_start;
+            range_idx = current_subpos - op->time_start;
             index = range_idx / range_dur;
         } else { /* fade out */
-            range_vol = mix->vol_end - mix->vol_start;
-            range_dur = mix->time_end - mix->time_start;
-            range_idx = mix->time_end - current_subpos;
+            range_vol = op->vol_end - op->vol_start;
+            range_dur = op->time_end - op->time_start;
+            range_idx = op->time_end - current_subpos;
             index = range_idx / range_dur;
         }
 
@@ -95,12 +95,12 @@ static bool get_fade_gain(mix_command_data *mix, float *out_cur_vol, int32_t cur
          * curves are complementary (exponential fade-in ~= logarithmic fade-out); the following
          * are described taking fade-in = normal.
          */
-        gain = get_fade_gain_curve(mix->shape, index);
+        gain = get_fade_gain_curve(op->shape, index);
 
-        if (mix->vol_start < mix->vol_end) {  /* fade in */
-            cur_vol = mix->vol_start + range_vol * gain;
+        if (op->vol_start < op->vol_end) {  /* fade in */
+            cur_vol = op->vol_start + range_vol * gain;
         } else { /* fade out */
-            cur_vol = mix->vol_end - range_vol * gain; //mix->vol_start - range_vol * (1 - gain);
+            cur_vol = op->vol_end - range_vol * gain; //mix->vol_start - range_vol * (1 - gain);
         }
     }
     else {
@@ -112,7 +112,7 @@ static bool get_fade_gain(mix_command_data *mix, float *out_cur_vol, int32_t cur
     return true;
 }
 
-void mixer_op_fade(mixer_data_t* data, int32_t sample_count, mix_command_data* mix) {
+void mixer_op_fade(mixer_data_t* data, int32_t sample_count, mix_op_t* mix) {
     float* sbuf = data->mixbuf;
     float new_gain = 0.0f;
 
@@ -145,11 +145,11 @@ void mixer_op_fade(mixer_data_t* data, int32_t sample_count, mix_command_data* m
 bool mixer_op_fade_is_active(mixer_data_t* data, int32_t current_start, int32_t current_end) {
 
     for (int i = 0; i < data->mixing_count; i++) {
-        mix_command_data* mix = &data->mixing_chain[i];
+        mix_op_t* mix = &data->mixing_chain[i];
         int32_t fade_start, fade_end;
         float vol_start = mix->vol_start;
 
-        if (mix->command != MIX_FADE)
+        if (mix->type != MIX_FADE)
             continue;
 
         /* check is current range falls within a fade
diff --git a/src/base/mixing_priv.h b/src/base/mixing_priv.h
index d0b39729..37196215 100644
--- a/src/base/mixing_priv.h
+++ b/src/base/mixing_priv.h
@@ -4,9 +4,6 @@
 
 #define VGMSTREAM_MAX_MIXING 512
 
-//TODO rename
-
-/* mixing info */
 typedef enum {
     MIX_SWAP,
     MIX_ADD,
@@ -16,10 +13,10 @@ typedef enum {
     MIX_DOWNMIX,
     MIX_KILLMIX,
     MIX_FADE
-} mix_command_t;
+} mix_type_t;
 
 typedef struct {
-    mix_command_t command;
+    mix_type_t type;
     /* common */
     int ch_dst;
     int ch_src;
@@ -33,7 +30,7 @@ typedef struct {
     int32_t time_start; /* fade start position where vol changes from vol_start to vol_end */
     int32_t time_end;   /* fade end position where vol changes from vol_start to vol_end */
     int32_t time_post;  /* position after time_end where vol_end applies (-1 = end) */
-} mix_command_data;
+} mix_op_t;
 
 typedef struct {
     int mixing_channels;    /* max channels needed to mix */
@@ -43,7 +40,7 @@ typedef struct {
 
     int mixing_count;       /* mixing number */
     size_t mixing_size;     /* mixing max */
-    mix_command_data mixing_chain[VGMSTREAM_MAX_MIXING]; /* effects to apply (could be alloc'ed but to simplify...) */
+    mix_op_t mixing_chain[VGMSTREAM_MAX_MIXING]; /* effects to apply (could be alloc'ed but to simplify...) */
 
     float* mixbuf;          /* internal mixing buffer */
     int current_channels;   /* state: channels may increase/decrease during ops */
@@ -54,13 +51,13 @@ typedef struct {
     bool has_fade;
 } mixer_data_t;
 
-void mixer_op_swap(mixer_data_t* data, int32_t sample_count, mix_command_data* mix);
-void mixer_op_add(mixer_data_t* data, int32_t sample_count, mix_command_data* mix);
-void mixer_op_volume(mixer_data_t* data, int32_t sample_count, mix_command_data* mix);
-void mixer_op_limit(mixer_data_t* data, int32_t sample_count, mix_command_data* mix);
-void mixer_op_upmix(mixer_data_t* data, int32_t sample_count, mix_command_data* mix);
-void mixer_op_downmix(mixer_data_t* data, int32_t sample_count, mix_command_data* mix);
-void mixer_op_killmix(mixer_data_t* data, int32_t sample_count, mix_command_data* mix);
-void mixer_op_fade(mixer_data_t* data, int32_t sample_count, mix_command_data* mix);
+void mixer_op_swap(mixer_data_t* data, int32_t sample_count, mix_op_t* op);
+void mixer_op_add(mixer_data_t* data, int32_t sample_count, mix_op_t* op);
+void mixer_op_volume(mixer_data_t* data, int32_t sample_count, mix_op_t* op);
+void mixer_op_limit(mixer_data_t* data, int32_t sample_count, mix_op_t* op);
+void mixer_op_upmix(mixer_data_t* data, int32_t sample_count, mix_op_t* op);
+void mixer_op_downmix(mixer_data_t* data, int32_t sample_count, mix_op_t* op);
+void mixer_op_killmix(mixer_data_t* data, int32_t sample_count, mix_op_t* op);
+void mixer_op_fade(mixer_data_t* data, int32_t sample_count, mix_op_t* op);
 bool mixer_op_fade_is_active(mixer_data_t* data, int32_t current_start, int32_t current_end);
 #endif