diff --git a/dlls/winegstreamer/gst_private.h b/dlls/winegstreamer/gst_private.h
index 2ac10ee37d3..31fca81ce6c 100644
--- a/dlls/winegstreamer/gst_private.h
+++ b/dlls/winegstreamer/gst_private.h
@@ -157,11 +157,11 @@ struct wg_parser
     pthread_cond_t read_cond, read_done_cond;
     struct
     {
-        GstBuffer *buffer;
+        void *data;
         uint64_t offset;
         uint32_t size;
         bool done;
-        GstFlowReturn ret;
+        bool ret;
     } read_request;
 
     bool flushing, sink_connected;
@@ -228,8 +228,8 @@ struct unix_funcs
     void (CDECL *wg_parser_end_flush)(struct wg_parser *parser);
 
     bool (CDECL *wg_parser_get_read_request)(struct wg_parser *parser,
-            GstBuffer **buffer, uint64_t *offset, uint32_t *size);
-    void (CDECL *wg_parser_complete_read_request)(struct wg_parser *parser, GstFlowReturn ret);
+            void **data, uint64_t *offset, uint32_t *size);
+    void (CDECL *wg_parser_complete_read_request)(struct wg_parser *parser, bool ret);
 
     uint32_t (CDECL *wg_parser_get_stream_count)(struct wg_parser *parser);
     struct wg_parser_stream *(CDECL *wg_parser_get_stream)(struct wg_parser *parser, uint32_t index);
diff --git a/dlls/winegstreamer/gstdemux.c b/dlls/winegstreamer/gstdemux.c
index 53977ed52c4..ab901a34843 100644
--- a/dlls/winegstreamer/gstdemux.c
+++ b/dlls/winegstreamer/gstdemux.c
@@ -787,25 +787,6 @@ static DWORD CALLBACK stream_thread(void *arg)
     return 0;
 }
 
-static GstFlowReturn read_buffer(struct parser *This, guint64 ofs, guint len, GstBuffer *buffer)
-{
-    HRESULT hr;
-    GstMapInfo info;
-
-    TRACE("filter %p, offset %s, length %u, buffer %p.\n", This, wine_dbgstr_longlong(ofs), len, buffer);
-
-    gst_buffer_map(buffer, &info, GST_MAP_WRITE);
-    hr = IAsyncReader_SyncRead(This->reader, ofs, len, info.data);
-    gst_buffer_unmap(buffer, &info);
-    if (FAILED(hr))
-    {
-        ERR("Failed to read data, hr %#x.\n", hr);
-        return GST_FLOW_ERROR;
-    }
-
-    return GST_FLOW_OK;
-}
-
 static DWORD CALLBACK read_thread(void *arg)
 {
     struct parser *filter = arg;
@@ -814,15 +795,15 @@ static DWORD CALLBACK read_thread(void *arg)
 
     while (filter->sink_connected)
     {
-        GstBuffer *buffer;
         uint64_t offset;
         uint32_t size;
+        HRESULT hr;
+        void *data;
 
-        if (!unix_funcs->wg_parser_get_read_request(filter->wg_parser, &buffer, &offset, &size))
+        if (!unix_funcs->wg_parser_get_read_request(filter->wg_parser, &data, &offset, &size))
             continue;
-
-        unix_funcs->wg_parser_complete_read_request(filter->wg_parser,
-                read_buffer(filter, offset, size, buffer));
+        hr = IAsyncReader_SyncRead(filter->reader, offset, size, data);
+        unix_funcs->wg_parser_complete_read_request(filter->wg_parser, SUCCEEDED(hr));
     }
 
     TRACE("Streaming stopped; exiting.\n");
diff --git a/dlls/winegstreamer/wg_parser.c b/dlls/winegstreamer/wg_parser.c
index 9fb3c4383fc..ccd60853007 100644
--- a/dlls/winegstreamer/wg_parser.c
+++ b/dlls/winegstreamer/wg_parser.c
@@ -350,11 +350,11 @@ static void CDECL wg_parser_end_flush(struct wg_parser *parser)
 }
 
 static bool CDECL wg_parser_get_read_request(struct wg_parser *parser,
-        GstBuffer **buffer, uint64_t *offset, uint32_t *size)
+        void **data, uint64_t *offset, uint32_t *size)
 {
     pthread_mutex_lock(&parser->mutex);
 
-    while (parser->sink_connected && !parser->read_request.buffer)
+    while (parser->sink_connected && !parser->read_request.data)
         pthread_cond_wait(&parser->read_cond, &parser->mutex);
 
     if (!parser->sink_connected)
@@ -363,7 +363,7 @@ static bool CDECL wg_parser_get_read_request(struct wg_parser *parser,
         return false;
     }
 
-    *buffer = parser->read_request.buffer;
+    *data = parser->read_request.data;
     *offset = parser->read_request.offset;
     *size = parser->read_request.size;
 
@@ -371,12 +371,12 @@ static bool CDECL wg_parser_get_read_request(struct wg_parser *parser,
     return true;
 }
 
-static void CDECL wg_parser_complete_read_request(struct wg_parser *parser, GstFlowReturn ret)
+static void CDECL wg_parser_complete_read_request(struct wg_parser *parser, bool ret)
 {
     pthread_mutex_lock(&parser->mutex);
     parser->read_request.done = true;
     parser->read_request.ret = ret;
-    parser->read_request.buffer = NULL;
+    parser->read_request.data = NULL;
     pthread_mutex_unlock(&parser->mutex);
     pthread_cond_signal(&parser->read_done_cond);
 }
@@ -985,7 +985,8 @@ static GstFlowReturn request_buffer_src(GstPad *pad, GstObject *parent, guint64
 {
     struct wg_parser *parser = gst_pad_get_element_private(pad);
     GstBuffer *new_buffer = NULL;
-    GstFlowReturn ret;
+    GstMapInfo map_info;
+    bool ret;
 
     GST_LOG("pad %p, offset %" G_GINT64_MODIFIER "u, length %u, buffer %p.", pad, offset, size, *buffer);
 
@@ -1000,10 +1001,12 @@ static GstFlowReturn request_buffer_src(GstPad *pad, GstObject *parent, guint64
     if (!*buffer)
         *buffer = new_buffer = gst_buffer_new_and_alloc(size);
 
+    gst_buffer_map(*buffer, &map_info, GST_MAP_WRITE);
+
     pthread_mutex_lock(&parser->mutex);
 
-    assert(!parser->read_request.buffer);
-    parser->read_request.buffer = *buffer;
+    assert(!parser->read_request.data);
+    parser->read_request.data = map_info.data;
     parser->read_request.offset = offset;
     parser->read_request.size = size;
     parser->read_request.done = false;
@@ -1020,12 +1023,14 @@ static GstFlowReturn request_buffer_src(GstPad *pad, GstObject *parent, guint64
 
     pthread_mutex_unlock(&parser->mutex);
 
-    GST_LOG("Request returned %s.", gst_flow_get_name(ret));
+    gst_buffer_unmap(*buffer, &map_info);
 
-    if (ret != GST_FLOW_OK && new_buffer)
+    GST_LOG("Request returned %d.", ret);
+
+    if (!ret && new_buffer)
         gst_buffer_unref(new_buffer);
 
-    return ret;
+    return ret ? GST_FLOW_OK : GST_FLOW_ERROR;
 }
 
 static gboolean query_function(GstPad *pad, GstObject *parent, GstQuery *query)