diff --git a/examples/webpmux.c b/examples/webpmux.c
index c292bb5b..55dfb28f 100644
--- a/examples/webpmux.c
+++ b/examples/webpmux.c
@@ -866,7 +866,7 @@ static int Process(const WebPMuxConfig* config) {
                 WebPDataFree(&alpha);
                 ERROR_GOTO1("ERROR: Could not parse frame properties.\n", Err2);
               }
-              err = WebPMuxAddFrame(mux, 0, &image, &alpha,
+              err = WebPMuxSetFrame(mux, 0, &image, &alpha,
                                     x_offset, y_offset, duration, 1);
               WebPDataFree(&image);
               WebPDataFree(&alpha);
@@ -897,7 +897,7 @@ static int Process(const WebPMuxConfig* config) {
               WebPDataFree(&alpha);
               ERROR_GOTO1("ERROR: Could not parse tile properties.\n", Err2);
             }
-            err = WebPMuxAddTile(mux, 0, &image, &alpha, x_offset, y_offset, 1);
+            err = WebPMuxSetTile(mux, 0, &image, &alpha, x_offset, y_offset, 1);
             WebPDataFree(&image);
             WebPDataFree(&alpha);
             if (err != WEBP_MUX_OK) {
diff --git a/src/mux/muxedit.c b/src/mux/muxedit.c
index 258da908..01376fb9 100644
--- a/src/mux/muxedit.c
+++ b/src/mux/muxedit.c
@@ -336,7 +336,7 @@ WebPMuxError WebPMuxSetLoopCount(WebPMux* const mux, uint32_t loop_count) {
   return err;
 }
 
-static WebPMuxError MuxAddFrameTileInternal(
+static WebPMuxError MuxSetFrameTileInternal(
     WebPMux* const mux, uint32_t nth,
     const WebPData* const image, const WebPData* const alpha,
     uint32_t x_offset, uint32_t y_offset, uint32_t duration,
@@ -428,22 +428,22 @@ static WebPMuxError MuxAddFrameTileInternal(
 
 // TODO(urvang): Think about whether we need 'nth' while adding a frame or tile.
 
-WebPMuxError WebPMuxAddFrame(WebPMux* const mux, uint32_t nth,
+WebPMuxError WebPMuxSetFrame(WebPMux* const mux, uint32_t nth,
                              const WebPData* const image,
                              const WebPData* const alpha,
                              uint32_t x_offset, uint32_t y_offset,
                              uint32_t duration, int copy_data) {
-  return MuxAddFrameTileInternal(mux, nth, image, alpha,
+  return MuxSetFrameTileInternal(mux, nth, image, alpha,
                                  x_offset, y_offset, duration,
                                  copy_data, kChunks[IDX_FRAME].tag);
 }
 
-WebPMuxError WebPMuxAddTile(WebPMux* const mux, uint32_t nth,
+WebPMuxError WebPMuxSetTile(WebPMux* const mux, uint32_t nth,
                             const WebPData* const image,
                             const WebPData* const alpha,
                             uint32_t x_offset, uint32_t y_offset,
                             int copy_data) {
-  return MuxAddFrameTileInternal(mux, nth, image, alpha,
+  return MuxSetFrameTileInternal(mux, nth, image, alpha,
                                  x_offset, y_offset, 1,
                                  copy_data, kChunks[IDX_TILE].tag);
 }
diff --git a/src/webp/mux.h b/src/webp/mux.h
index 3e9e9104..d96dacca 100644
--- a/src/webp/mux.h
+++ b/src/webp/mux.h
@@ -274,7 +274,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxDeleteColorProfile(WebPMux* const mux);
 //   WEBP_MUX_NOT_FOUND - If we have less than (nth-1) frames before adding.
 //   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxAddFrame(
+WEBP_EXTERN(WebPMuxError) WebPMuxSetFrame(
     WebPMux* const mux, uint32_t nth,
     const WebPData* const image, const WebPData* const alpha,
     uint32_t x_offset, uint32_t y_offset, uint32_t duration,
@@ -368,7 +368,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxGetLoopCount(const WebPMux* const mux,
 //   WEBP_MUX_NOT_FOUND - If we have less than (nth-1) tiles before adding.
 //   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxAddTile(
+WEBP_EXTERN(WebPMuxError) WebPMuxSetTile(
     WebPMux* const mux, uint32_t nth,
     const WebPData* const image, const WebPData* const alpha,
     uint32_t x_offset, uint32_t y_offset,