diff --git a/libavfilter/vf_paletteuse.c b/libavfilter/vf_paletteuse.c
index ffd37bf1da..4203543843 100644
--- a/libavfilter/vf_paletteuse.c
+++ b/libavfilter/vf_paletteuse.c
@@ -56,7 +56,7 @@ enum diff_mode {
 };
 
 struct color_node {
-    uint8_t val[3];
+    uint8_t val[4];
     uint8_t palette_id;
     int split;
     int left_id, right_id;
@@ -86,6 +86,7 @@ typedef struct PaletteUseContext {
     struct cache_node cache[CACHE_SIZE];    /* lookup cache */
     struct color_node map[AVPALETTE_COUNT]; /* 3D-Tree (KD-Tree with K=3) for reverse colormap */
     uint32_t palette[AVPALETTE_COUNT];
+    int transparency_index; /* index in the palette of transparency. -1 if there isn't a transparency. */
     int palette_loaded;
     int dither;
     int new;
@@ -108,6 +109,7 @@ typedef struct PaletteUseContext {
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 static const AVOption paletteuse_options[] = {
     { "dither", "select dithering mode", OFFSET(dither), AV_OPT_TYPE_INT, {.i64=DITHERING_SIERRA2_4A}, 0, NB_DITHERING-1, FLAGS, "dithering_mode" },
+        { "none",            "no dither",                                                              0, AV_OPT_TYPE_CONST, {.i64=DITHERING_NONE},            INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
         { "bayer",           "ordered 8x8 bayer dithering (deterministic)",                            0, AV_OPT_TYPE_CONST, {.i64=DITHERING_BAYER},           INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
         { "heckbert",        "dithering as defined by Paul Heckbert in 1982 (simple error diffusion)", 0, AV_OPT_TYPE_CONST, {.i64=DITHERING_HECKBERT},        INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
         { "floyd_steinberg", "Floyd and Steingberg dithering (error diffusion)",                       0, AV_OPT_TYPE_CONST, {.i64=DITHERING_FLOYD_STEINBERG}, INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
@@ -157,7 +159,8 @@ static int query_formats(AVFilterContext *ctx)
 
 static av_always_inline int dither_color(uint32_t px, int er, int eg, int eb, int scale, int shift)
 {
-    return av_clip_uint8((px >> 16 & 0xff) + ((er * scale) / (1<<shift))) << 16
+    return av_clip_uint8((px >> 24 & 0xff)                              ) << 24
+         | av_clip_uint8((px >> 16 & 0xff) + ((er * scale) / (1<<shift))) << 16
          | av_clip_uint8((px >>  8 & 0xff) + ((eg * scale) / (1<<shift))) <<  8
          | av_clip_uint8((px       & 0xff) + ((eb * scale) / (1<<shift)));
 }
@@ -165,10 +168,18 @@ static av_always_inline int dither_color(uint32_t px, int er, int eg, int eb, in
 static av_always_inline int diff(const uint8_t *c1, const uint8_t *c2)
 {
     // XXX: try L*a*b with CIE76 (dL*dL + da*da + db*db)
-    const int dr = c1[0] - c2[0];
-    const int dg = c1[1] - c2[1];
-    const int db = c1[2] - c2[2];
-    return dr*dr + dg*dg + db*db;
+    const static int max_diff = 255*255 + 255*255 + 255*255;
+    const int dr = c1[1] - c2[1];
+    const int dg = c1[2] - c2[2];
+    const int db = c1[3] - c2[3];
+
+    if (c1[0] == 0 && c2[0] == 0) {
+        return 0;
+    } else if (c1[0] == c2[0]) {
+        return dr*dr + dg*dg + db*db;
+    } else {
+        return max_diff;
+    }
 }
 
 static av_always_inline uint8_t colormap_nearest_bruteforce(const uint32_t *palette, const uint8_t *rgb)
@@ -179,18 +190,20 @@ static av_always_inline uint8_t colormap_nearest_bruteforce(const uint32_t *pale
         const uint32_t c = palette[i];
 
         if ((c & 0xff000000) == 0xff000000) { // ignore transparent entry
-            const uint8_t palrgb[] = {
+            const uint8_t palargb[] = {
+                palette[i]>>24 & 0xff,
                 palette[i]>>16 & 0xff,
                 palette[i]>> 8 & 0xff,
                 palette[i]     & 0xff,
             };
-            const int d = diff(palrgb, rgb);
+            const int d = diff(palargb, rgb);
             if (d < min_dist) {
                 pal_id = i;
                 min_dist = d;
             }
         }
     }
+
     return pal_id;
 }
 
@@ -325,14 +338,15 @@ end:
  * Note: r, g, and b are the component of c but are passed as well to avoid
  * recomputing them (they are generally computed by the caller for other uses).
  */
-static av_always_inline int color_get(struct cache_node *cache, uint32_t color,
-                                      uint8_t r, uint8_t g, uint8_t b,
+static av_always_inline int color_get(struct cache_node *cache, uint32_t argb,
+                                      uint8_t a, uint8_t r, uint8_t g, uint8_t b,
+                                      int transparency_index,
                                       const struct color_node *map,
                                       const uint32_t *palette,
                                       const enum color_search_method search_method)
 {
     int i;
-    const uint8_t rgb[] = {r, g, b};
+    const uint8_t argb_elts[] = {a, r, g, b};
     const uint8_t rhash = r & ((1<<NBITS)-1);
     const uint8_t ghash = g & ((1<<NBITS)-1);
     const uint8_t bhash = b & ((1<<NBITS)-1);
@@ -340,9 +354,14 @@ static av_always_inline int color_get(struct cache_node *cache, uint32_t color,
     struct cache_node *node = &cache[hash];
     struct cached_color *e;
 
+    // first, check for transparency
+    if (a == 0 && transparency_index >= 0) {
+        return transparency_index;
+    }
+
     for (i = 0; i < node->nb_entries; i++) {
         e = &node->entries[i];
-        if (e->color == color)
+        if (e->color == argb)
             return e->pal_entry;
     }
 
@@ -350,21 +369,24 @@ static av_always_inline int color_get(struct cache_node *cache, uint32_t color,
                          sizeof(*node->entries), NULL);
     if (!e)
         return AVERROR(ENOMEM);
-    e->color = color;
-    e->pal_entry = COLORMAP_NEAREST(search_method, palette, map, rgb);
+    e->color = argb;
+    e->pal_entry = COLORMAP_NEAREST(search_method, palette, map, argb_elts);
+
     return e->pal_entry;
 }
 
 static av_always_inline int get_dst_color_err(struct cache_node *cache,
-                                              uint32_t c, const struct color_node *map,
+                                              uint32_t argb, const struct color_node *map,
                                               const uint32_t *palette,
+                                              int transparency_index,
                                               int *er, int *eg, int *eb,
                                               const enum color_search_method search_method)
 {
-    const uint8_t r = c >> 16 & 0xff;
-    const uint8_t g = c >>  8 & 0xff;
-    const uint8_t b = c       & 0xff;
-    const int dstx = color_get(cache, c, r, g, b, map, palette, search_method);
+    const uint8_t a = argb >> 24 & 0xff;
+    const uint8_t r = argb >> 16 & 0xff;
+    const uint8_t g = argb >>  8 & 0xff;
+    const uint8_t b = argb       & 0xff;
+    const int dstx = color_get(cache, argb, a, r, g, b, transparency_index, map, palette, search_method);
     const uint32_t dstc = palette[dstx];
     *er = r - (dstc >> 16 & 0xff);
     *eg = g - (dstc >>  8 & 0xff);
@@ -385,6 +407,7 @@ static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFram
     const int dst_linesize = out->linesize[0];
     uint32_t *src = ((uint32_t *)in ->data[0]) + y_start*src_linesize;
     uint8_t  *dst =              out->data[0]  + y_start*dst_linesize;
+    int transparency_index = s->transparency_index;
 
     w += x_start;
     h += y_start;
@@ -395,14 +418,14 @@ static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFram
 
             if (dither == DITHERING_BAYER) {
                 const int d = s->ordered_dither[(y & 7)<<3 | (x & 7)];
+                const uint8_t a8 = src[x] >> 24 & 0xff;
                 const uint8_t r8 = src[x] >> 16 & 0xff;
                 const uint8_t g8 = src[x] >>  8 & 0xff;
                 const uint8_t b8 = src[x]       & 0xff;
                 const uint8_t r = av_clip_uint8(r8 + d);
                 const uint8_t g = av_clip_uint8(g8 + d);
                 const uint8_t b = av_clip_uint8(b8 + d);
-                const uint32_t c = r<<16 | g<<8 | b;
-                const int color = color_get(cache, c, r, g, b, map, palette, search_method);
+                const int color = color_get(cache, src[x], a8, r, g, b, transparency_index, map, palette, search_method);
 
                 if (color < 0)
                     return color;
@@ -410,7 +433,7 @@ static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFram
 
             } else if (dither == DITHERING_HECKBERT) {
                 const int right = x < w - 1, down = y < h - 1;
-                const int color = get_dst_color_err(cache, src[x], map, palette, &er, &eg, &eb, search_method);
+                const int color = get_dst_color_err(cache, src[x], map, palette, transparency_index, &er, &eg, &eb, search_method);
 
                 if (color < 0)
                     return color;
@@ -422,7 +445,7 @@ static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFram
 
             } else if (dither == DITHERING_FLOYD_STEINBERG) {
                 const int right = x < w - 1, down = y < h - 1, left = x > x_start;
-                const int color = get_dst_color_err(cache, src[x], map, palette, &er, &eg, &eb, search_method);
+                const int color = get_dst_color_err(cache, src[x], map, palette, transparency_index, &er, &eg, &eb, search_method);
 
                 if (color < 0)
                     return color;
@@ -436,7 +459,7 @@ static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFram
             } else if (dither == DITHERING_SIERRA2) {
                 const int right  = x < w - 1, down  = y < h - 1, left  = x > x_start;
                 const int right2 = x < w - 2,                    left2 = x > x_start + 1;
-                const int color = get_dst_color_err(cache, src[x], map, palette, &er, &eg, &eb, search_method);
+                const int color = get_dst_color_err(cache, src[x], map, palette, transparency_index, &er, &eg, &eb, search_method);
 
                 if (color < 0)
                     return color;
@@ -455,7 +478,7 @@ static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFram
 
             } else if (dither == DITHERING_SIERRA2_4A) {
                 const int right = x < w - 1, down = y < h - 1, left = x > x_start;
-                const int color = get_dst_color_err(cache, src[x], map, palette, &er, &eg, &eb, search_method);
+                const int color = get_dst_color_err(cache, src[x], map, palette, transparency_index, &er, &eg, &eb, search_method);
 
                 if (color < 0)
                     return color;
@@ -466,10 +489,11 @@ static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFram
                 if (         down) src[src_linesize + x    ] = dither_color(src[src_linesize + x    ], er, eg, eb, 1, 2);
 
             } else {
+                const uint8_t a = src[x] >> 24 & 0xff;
                 const uint8_t r = src[x] >> 16 & 0xff;
                 const uint8_t g = src[x] >>  8 & 0xff;
                 const uint8_t b = src[x]       & 0xff;
-                const int color = color_get(cache, src[x] & 0xffffff, r, g, b, map, palette, search_method);
+                const int color = color_get(cache, src[x], a, r, g, b, transparency_index, map, palette, search_method);
 
                 if (color < 0)
                     return color;
@@ -489,19 +513,19 @@ static void disp_node(AVBPrint *buf,
                       int depth)
 {
     const struct color_node *node = &map[node_id];
-    const uint32_t fontcolor = node->val[0] > 0x50 &&
-                               node->val[1] > 0x50 &&
-                               node->val[2] > 0x50 ? 0 : 0xffffff;
+    const uint32_t fontcolor = node->val[1] > 0x50 &&
+                               node->val[2] > 0x50 &&
+                               node->val[3] > 0x50 ? 0 : 0xffffff;
     av_bprintf(buf, "%*cnode%d ["
                "label=\"%c%02X%c%02X%c%02X%c\" "
                "fillcolor=\"#%02x%02x%02x\" "
                "fontcolor=\"#%06"PRIX32"\"]\n",
                depth*INDENT, ' ', node->palette_id,
-               "[  "[node->split], node->val[0],
-               "][ "[node->split], node->val[1],
-               " ]["[node->split], node->val[2],
+               "[  "[node->split], node->val[1],
+               "][ "[node->split], node->val[2],
+               " ]["[node->split], node->val[3],
                "  ]"[node->split],
-               node->val[0], node->val[1], node->val[2],
+               node->val[1], node->val[2], node->val[3],
                fontcolor);
     if (parent_id != -1)
         av_bprintf(buf, "%*cnode%d -> node%d\n", depth*INDENT, ' ',
@@ -584,17 +608,18 @@ static int cmp_##name(const void *pa, const void *pb)   \
 {                                                       \
     const struct color *a = pa;                         \
     const struct color *b = pb;                         \
-    return   (a->value >> (8 * (2 - (pos))) & 0xff)     \
-           - (b->value >> (8 * (2 - (pos))) & 0xff);    \
+    return   (a->value >> (8 * (3 - (pos))) & 0xff)     \
+           - (b->value >> (8 * (3 - (pos))) & 0xff);    \
 }
 
-DECLARE_CMP_FUNC(r, 0)
-DECLARE_CMP_FUNC(g, 1)
-DECLARE_CMP_FUNC(b, 2)
+DECLARE_CMP_FUNC(a, 0)
+DECLARE_CMP_FUNC(r, 1)
+DECLARE_CMP_FUNC(g, 2)
+DECLARE_CMP_FUNC(b, 3)
 
-static const cmp_func cmp_funcs[] = {cmp_r, cmp_g, cmp_b};
+static const cmp_func cmp_funcs[] = {cmp_a, cmp_r, cmp_g, cmp_b};
 
-static int get_next_color(const uint8_t *color_used, const uint32_t *palette,
+static int get_next_color(const uint8_t *color_used, const uint32_t *palette, const int nb_colors,
                           int *component, const struct color_rect *box)
 {
     int wr, wg, wb;
@@ -607,13 +632,18 @@ static int get_next_color(const uint8_t *color_used, const uint32_t *palette,
     ranges.min[0] = ranges.min[1] = ranges.min[2] = 0xff;
     ranges.max[0] = ranges.max[1] = ranges.max[2] = 0x00;
 
-    for (i = 0; i < AVPALETTE_COUNT; i++) {
+    for (i = 0; i < nb_colors; i++) {
         const uint32_t c = palette[i];
+        const uint8_t a = c >> 24 & 0xff;
         const uint8_t r = c >> 16 & 0xff;
         const uint8_t g = c >>  8 & 0xff;
         const uint8_t b = c       & 0xff;
 
-        if (color_used[i] ||
+        if (a != 0xff) {
+            continue;
+        }
+
+        if (color_used[i] || (a != 0xff) ||
             r < box->min[0] || g < box->min[1] || b < box->min[2] ||
             r > box->max[0] || g > box->max[1] || b > box->max[2])
             continue;
@@ -639,9 +669,9 @@ static int get_next_color(const uint8_t *color_used, const uint32_t *palette,
     wr = ranges.max[0] - ranges.min[0];
     wg = ranges.max[1] - ranges.min[1];
     wb = ranges.max[2] - ranges.min[2];
-    if (wr >= wg && wr >= wb) longest = 0;
-    if (wg >= wr && wg >= wb) longest = 1;
-    if (wb >= wr && wb >= wg) longest = 2;
+    if (wr >= wg && wr >= wb) longest = 1;
+    if (wg >= wr && wg >= wb) longest = 2;
+    if (wb >= wr && wb >= wg) longest = 3;
     cmpf = cmp_funcs[longest];
     *component = longest;
 
@@ -655,6 +685,7 @@ static int colormap_insert(struct color_node *map,
                            uint8_t *color_used,
                            int *nb_used,
                            const uint32_t *palette,
+                           const int nb_colors,
                            const struct color_rect *box)
 {
     uint32_t c;
@@ -662,7 +693,7 @@ static int colormap_insert(struct color_node *map,
     int node_left_id = -1, node_right_id = -1;
     struct color_node *node;
     struct color_rect box1, box2;
-    const int pal_id = get_next_color(color_used, palette, &component, box);
+    const int pal_id = get_next_color(color_used, palette, nb_colors, &component, box);
 
     if (pal_id < 0)
         return -1;
@@ -673,21 +704,22 @@ static int colormap_insert(struct color_node *map,
     node = &map[cur_id];
     node->split = component;
     node->palette_id = pal_id;
-    node->val[0] = c>>16 & 0xff;
-    node->val[1] = c>> 8 & 0xff;
-    node->val[2] = c     & 0xff;
+    node->val[0] = c>>24 & 0xff;
+    node->val[1] = c>>16 & 0xff;
+    node->val[2] = c>> 8 & 0xff;
+    node->val[3] = c     & 0xff;
 
     color_used[pal_id] = 1;
 
     /* get the two boxes this node creates */
     box1 = box2 = *box;
-    box1.max[component] = node->val[component];
-    box2.min[component] = node->val[component] + 1;
+    box1.max[component-1] = node->val[component];
+    box2.min[component-1] = node->val[component] + 1;
 
-    node_left_id = colormap_insert(map, color_used, nb_used, palette, &box1);
+    node_left_id = colormap_insert(map, color_used, nb_used, palette, nb_colors, &box1);
 
-    if (box2.min[component] <= box2.max[component])
-        node_right_id = colormap_insert(map, color_used, nb_used, palette, &box2);
+    if (box2.min[component-1] <= box2.max[component-1])
+        node_right_id = colormap_insert(map, color_used, nb_used, palette, nb_colors, &box2);
 
     node->left_id  = node_left_id;
     node->right_id = node_right_id;
@@ -702,7 +734,7 @@ static int cmp_pal_entry(const void *a, const void *b)
     return c1 - c2;
 }
 
-static void load_colormap(PaletteUseContext *s)
+static void load_colormap(PaletteUseContext *s, int nb_colors)
 {
     int i, nb_used = 0;
     uint8_t color_used[AVPALETTE_COUNT] = {0};
@@ -710,8 +742,18 @@ static void load_colormap(PaletteUseContext *s)
     struct color_rect box;
 
     /* disable transparent colors and dups */
-    qsort(s->palette, AVPALETTE_COUNT, sizeof(*s->palette), cmp_pal_entry);
-    for (i = 0; i < AVPALETTE_COUNT; i++) {
+    qsort(s->palette, nb_colors, sizeof(*s->palette), cmp_pal_entry);
+    // update transparency index:
+    if (s->transparency_index >= 0) {
+        for (i = 0; i < nb_colors; i++) {
+            if ((s->palette[i]>>24 & 0xff) == 0) {
+                s->transparency_index = i; // we are assuming at most one transparent color
+                break;
+            }
+        }
+    }
+
+    for (i = 0; i < nb_colors; i++) {
         const uint32_t c = s->palette[i];
         if (i != 0 && c == last_color) {
             color_used[i] = 1;
@@ -727,7 +769,7 @@ static void load_colormap(PaletteUseContext *s)
     box.min[0] = box.min[1] = box.min[2] = 0x00;
     box.max[0] = box.max[1] = box.max[2] = 0xff;
 
-    colormap_insert(s->map, color_used, &nb_used, s->palette, &box);
+    colormap_insert(s->map, color_used, &nb_used, s->palette, nb_colors, &box);
 
     if (s->dot_filename)
         disp_tree(s->map, s->dot_filename);
@@ -937,10 +979,12 @@ static int config_input_palette(AVFilterLink *inlink)
 
 static void load_palette(PaletteUseContext *s, const AVFrame *palette_frame)
 {
-    int i, x, y;
+    int pal_index, i, x, y;
     const uint32_t *p = (const uint32_t *)palette_frame->data[0];
     const int p_linesize = palette_frame->linesize[0] >> 2;
 
+    s->transparency_index = -1;
+
     if (s->new) {
         memset(s->palette, 0, sizeof(s->palette));
         memset(s->map, 0, sizeof(s->map));
@@ -949,14 +993,19 @@ static void load_palette(PaletteUseContext *s, const AVFrame *palette_frame)
         memset(s->cache, 0, sizeof(s->cache));
     }
 
-    i = 0;
+    pal_index = 0;
     for (y = 0; y < palette_frame->height; y++) {
-        for (x = 0; x < palette_frame->width; x++)
-            s->palette[i++] = p[x];
+        for (x = 0; x < palette_frame->width; x++) {
+            s->palette[pal_index] = p[x];
+            if ((p[x]>>24 & 0xff) == 0) {
+                s->transparency_index = pal_index; // we are assuming at most one transparent color
+            }
+            ++pal_index;
+        }
         p += p_linesize;
     }
 
-    load_colormap(s);
+    load_colormap(s, pal_index);
 
     if (!s->new)
         s->palette_loaded = 1;
