diff --git a/dlls/winegstreamer/gst_private.h b/dlls/winegstreamer/gst_private.h
index c29fc4a2437..49e06b31369 100644
--- a/dlls/winegstreamer/gst_private.h
+++ b/dlls/winegstreamer/gst_private.h
@@ -170,9 +170,10 @@ struct unix_funcs
     void (CDECL *wg_parser_begin_flush)(struct wg_parser *parser);
     void (CDECL *wg_parser_end_flush)(struct wg_parser *parser);
 
-    bool (CDECL *wg_parser_get_read_request)(struct wg_parser *parser,
-            void **data, uint64_t *offset, uint32_t *size);
-    void (CDECL *wg_parser_complete_read_request)(struct wg_parser *parser, bool ret);
+    bool (CDECL *wg_parser_get_next_read_offset)(struct wg_parser *parser,
+            uint64_t *offset, uint32_t *size);
+    void (CDECL *wg_parser_push_data)(struct wg_parser *parser,
+            const void *data, uint32_t size);
 
     void (CDECL *wg_parser_set_unlimited_buffering)(struct wg_parser *parser);
 
diff --git a/dlls/winegstreamer/media_source.c b/dlls/winegstreamer/media_source.c
index 95bdb9b488e..825bad8da27 100644
--- a/dlls/winegstreamer/media_source.c
+++ b/dlls/winegstreamer/media_source.c
@@ -530,6 +530,11 @@ static DWORD CALLBACK read_thread(void *arg)
 {
     struct media_source *source = arg;
     IMFByteStream *byte_stream = source->byte_stream;
+    uint32_t buffer_size = 0;
+    uint64_t file_size;
+    void *data = NULL;
+
+    IMFByteStream_GetLength(byte_stream, &file_size);
 
     TRACE("Starting read thread for media source %p.\n", source);
 
@@ -539,18 +544,33 @@ static DWORD CALLBACK read_thread(void *arg)
         ULONG ret_size;
         uint32_t size;
         HRESULT hr;
-        void *data;
 
-        if (!unix_funcs->wg_parser_get_read_request(source->wg_parser, &data, &offset, &size))
+        if (!unix_funcs->wg_parser_get_next_read_offset(source->wg_parser, &offset, &size))
             continue;
 
+        if (offset >= file_size)
+            size = 0;
+        else if (offset + size >= file_size)
+            size = file_size - offset;
+
+        if (size > buffer_size)
+        {
+            buffer_size = size;
+            data = realloc(data, size);
+        }
+
+        ret_size = 0;
+
         if (SUCCEEDED(hr = IMFByteStream_SetCurrentPosition(byte_stream, offset)))
             hr = IMFByteStream_Read(byte_stream, data, size, &ret_size);
-        if (SUCCEEDED(hr) && ret_size != size)
+        if (FAILED(hr))
+            ERR("Failed to read %u bytes at offset %I64u, hr %#x.\n", size, offset, hr);
+        else if (ret_size != size)
             ERR("Unexpected short read: requested %u bytes, got %u.\n", size, ret_size);
-        unix_funcs->wg_parser_complete_read_request(source->wg_parser, SUCCEEDED(hr));
+        unix_funcs->wg_parser_push_data(source->wg_parser, SUCCEEDED(hr) ? data : NULL, ret_size);
     }
 
+    free(data);
     TRACE("Media source is shutting down; exiting.\n");
     return 0;
 }
diff --git a/dlls/winegstreamer/quartz_parser.c b/dlls/winegstreamer/quartz_parser.c
index 09a916d7f5c..5299f4dc2ed 100644
--- a/dlls/winegstreamer/quartz_parser.c
+++ b/dlls/winegstreamer/quartz_parser.c
@@ -785,6 +785,11 @@ static DWORD CALLBACK stream_thread(void *arg)
 static DWORD CALLBACK read_thread(void *arg)
 {
     struct parser *filter = arg;
+    LONGLONG file_size, unused;
+    uint32_t buffer_size = 0;
+    void *data = NULL;
+
+    IAsyncReader_Length(filter->reader, &file_size, &unused);
 
     TRACE("Starting read thread for filter %p.\n", filter);
 
@@ -793,14 +798,29 @@ static DWORD CALLBACK read_thread(void *arg)
         uint64_t offset;
         uint32_t size;
         HRESULT hr;
-        void *data;
 
-        if (!unix_funcs->wg_parser_get_read_request(filter->wg_parser, &data, &offset, &size))
+        if (!unix_funcs->wg_parser_get_next_read_offset(filter->wg_parser, &offset, &size))
             continue;
+
+        if (offset >= file_size)
+            size = 0;
+        else if (offset + size >= file_size)
+            size = file_size - offset;
+
+        if (size > buffer_size)
+        {
+            buffer_size = size;
+            data = realloc(data, size);
+        }
+
         hr = IAsyncReader_SyncRead(filter->reader, offset, size, data);
-        unix_funcs->wg_parser_complete_read_request(filter->wg_parser, SUCCEEDED(hr));
+        if (FAILED(hr))
+            ERR("Failed to read %u bytes at offset %I64u, hr %#x.\n", size, offset, hr);
+
+        unix_funcs->wg_parser_push_data(filter->wg_parser, SUCCEEDED(hr) ? data : NULL, size);
     }
 
+    free(data);
     TRACE("Streaming stopped; exiting.\n");
     return 0;
 }
diff --git a/dlls/winegstreamer/wg_parser.c b/dlls/winegstreamer/wg_parser.c
index 119cbffbd88..f0815e37689 100644
--- a/dlls/winegstreamer/wg_parser.c
+++ b/dlls/winegstreamer/wg_parser.c
@@ -517,8 +517,8 @@ static void CDECL wg_parser_end_flush(struct wg_parser *parser)
     pthread_mutex_unlock(&parser->mutex);
 }
 
-static bool CDECL wg_parser_get_read_request(struct wg_parser *parser,
-        void **data, uint64_t *offset, uint32_t *size)
+static bool CDECL wg_parser_get_next_read_offset(struct wg_parser *parser,
+        uint64_t *offset, uint32_t *size)
 {
     pthread_mutex_lock(&parser->mutex);
 
@@ -531,7 +531,6 @@ static bool CDECL wg_parser_get_read_request(struct wg_parser *parser,
         return false;
     }
 
-    *data = parser->read_request.data;
     *offset = parser->read_request.offset;
     *size = parser->read_request.size;
 
@@ -539,11 +538,15 @@ 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, bool ret)
+static void CDECL wg_parser_push_data(struct wg_parser *parser,
+        const void *data, uint32_t size)
 {
     pthread_mutex_lock(&parser->mutex);
+    parser->read_request.size = size;
     parser->read_request.done = true;
-    parser->read_request.ret = ret;
+    parser->read_request.ret = !!data;
+    if (data)
+        memcpy(parser->read_request.data, data, size);
     parser->read_request.data = NULL;
     pthread_mutex_unlock(&parser->mutex);
     pthread_cond_signal(&parser->read_done_cond);
@@ -1214,10 +1217,6 @@ static GstFlowReturn src_getrange_cb(GstPad *pad, GstObject *parent,
     if (offset == GST_BUFFER_OFFSET_NONE)
         offset = parser->next_pull_offset;
     parser->next_pull_offset = offset + size;
-    if (offset >= parser->file_size)
-        return GST_FLOW_EOS;
-    if (offset + size >= parser->file_size)
-        size = parser->file_size - offset;
 
     if (!*buffer)
         *buffer = new_buffer = gst_buffer_new_and_alloc(size);
@@ -1241,6 +1240,7 @@ static GstFlowReturn src_getrange_cb(GstPad *pad, GstObject *parent,
         pthread_cond_wait(&parser->read_done_cond, &parser->mutex);
 
     ret = parser->read_request.ret;
+    gst_buffer_set_size(*buffer, parser->read_request.size);
 
     pthread_mutex_unlock(&parser->mutex);
 
@@ -1248,10 +1248,12 @@ static GstFlowReturn src_getrange_cb(GstPad *pad, GstObject *parent,
 
     GST_LOG("Request returned %d.", ret);
 
-    if (!ret && new_buffer)
+    if ((!ret || !size) && new_buffer)
         gst_buffer_unref(new_buffer);
 
-    return ret ? GST_FLOW_OK : GST_FLOW_ERROR;
+    if (ret)
+        return size ? GST_FLOW_OK : GST_FLOW_EOS;
+    return GST_FLOW_ERROR;
 }
 
 static gboolean src_query_cb(GstPad *pad, GstObject *parent, GstQuery *query)
@@ -1918,8 +1920,8 @@ static const struct unix_funcs funcs =
     wg_parser_begin_flush,
     wg_parser_end_flush,
 
-    wg_parser_get_read_request,
-    wg_parser_complete_read_request,
+    wg_parser_get_next_read_offset,
+    wg_parser_push_data,
 
     wg_parser_set_unlimited_buffering,