diff --git a/common/xrdp_client_info.h b/common/xrdp_client_info.h
index 8313d0ae..d1ce1e1e 100644
--- a/common/xrdp_client_info.h
+++ b/common/xrdp_client_info.h
@@ -134,6 +134,14 @@ struct xrdp_client_info
   char variant[16];
   char options[256];
 
+  /* codec */
+  int h264_codec_id;
+  int h264_prop_len;
+  char h264_prop[64];
+
+  int use_frame_acks;
+  int max_unacknowledged_frame_count;
+
 };
 
 #endif
diff --git a/common/xrdp_constants.h b/common/xrdp_constants.h
index 25d9495f..b8739b2b 100644
--- a/common/xrdp_constants.h
+++ b/common/xrdp_constants.h
@@ -557,6 +557,10 @@
 #define XR_CODEC_GUID_PNG \
   "\x8D\x85\x0C\x0E\xE0\x28\xDB\x45\xAD\xAA\x0F\x83\xE5\x7C\xC5\x60"
 
+/* MFVideoFormat_H264 ({34363248-0000-0010-8000-00AA00389B71}) */
+#define XR_CODEC_GUID_H264 \
+  "\x48\x32\x36\x34\x00\x00\x10\x00\x80\x00\x00\xAA\x00\x38\x9B\x71"
+
 #define RDP_CAPSET_SURFCMDS       0x1c
 #define RDP_CAPLEN_SURFCMDS       0x0c
 #define RDP_CAPSET_BMPCODECS      0x1d
diff --git a/libxrdp/libxrdp.c b/libxrdp/libxrdp.c
index 594fcc73..32ee2098 100644
--- a/libxrdp/libxrdp.c
+++ b/libxrdp/libxrdp.c
@@ -1312,7 +1312,7 @@ libxrdp_fastpath_send_surface(struct xrdp_session *session,
     int max_bytes;
     int cmd_bytes;
 
-    LLOGLN(10, ("libxrdp_fastpath_init:"));
+    LLOGLN(10, ("libxrdp_fastpath_send_surface:"));
     if ((session->client_info->use_fast_path & 1) == 0)
     {
         return 1;
@@ -1362,3 +1362,40 @@ libxrdp_fastpath_send_surface(struct xrdp_session *session,
     }
     return 0;
 }
+
+/*****************************************************************************/
+int EXPORT_CC
+libxrdp_fastpath_send_frame_marker(struct xrdp_session *session,
+                                   int frame_action, int frame_id)
+{
+    struct stream *s;
+    struct xrdp_rdp *rdp;
+
+    LLOGLN(10, ("libxrdp_fastpath_send_frame_marker:"));
+    if ((session->client_info->use_fast_path & 1) == 0)
+    {
+        return 1;
+    }
+    if (session->client_info->use_frame_acks == 0)
+    {
+        return 1;
+    }
+    rdp = (struct xrdp_rdp *) (session->rdp);
+    make_stream(s);
+    init_stream(s, 8192);
+    xrdp_rdp_init_fastpath(rdp, s);
+    out_uint16_le(s, 0x0004); /* CMDTYPE_FRAME_MARKER */
+    out_uint16_le(s, frame_action);
+    out_uint32_le(s, frame_id);
+    s_mark_end(s);
+    /* 4 = FASTPATH_UPDATETYPE_SURFCMDS */
+    if (xrdp_rdp_send_fastpath(rdp, s, 4) != 0)
+    {
+        free_stream(s);
+        return 1;
+    }
+    free_stream(s);
+    return 0;
+
+}
+
diff --git a/libxrdp/libxrdpinc.h b/libxrdp/libxrdpinc.h
index 2262f66f..8d99814c 100644
--- a/libxrdp/libxrdpinc.h
+++ b/libxrdp/libxrdpinc.h
@@ -242,5 +242,8 @@ libxrdp_fastpath_send_surface(struct xrdp_session *session,
                               int destLeft, int dst_Top,
                               int destRight, int destBottom, int bpp,
                               int codecID, int width, int height);
+int EXPORT_CC
+libxrdp_fastpath_send_frame_marker(struct xrdp_session *session,
+                                   int frame_action, int frame_id);
 
 #endif
diff --git a/libxrdp/xrdp_caps.c b/libxrdp/xrdp_caps.c
index a5883a01..98ab03fa 100644
--- a/libxrdp/xrdp_caps.c
+++ b/libxrdp/xrdp_caps.c
@@ -486,6 +486,15 @@ xrdp_caps_process_codecs(struct xrdp_rdp *self, struct stream *s, int len)
             }
             g_writeln("  jpeg quality set to %d", self->client_info.jpeg_prop[0]);
         }
+        else if (g_memcmp(codec_guid, XR_CODEC_GUID_H264, 16) == 0)
+        {
+            g_writeln("xrdp_caps_process_codecs: h264 codec id %d prop len %d",
+                      codec_id, codec_properties_length);
+            self->client_info.h264_codec_id = codec_id;
+            i1 = MIN(64, codec_properties_length);
+            g_memcpy(self->client_info.h264_prop, s->p, i1);
+            self->client_info.h264_prop_len = i1;
+        }
         else
         {
             g_writeln("xrdp_caps_process_codecs: unknown codec id %d", codec_id);
@@ -509,6 +518,17 @@ xrdp_caps_process_multifragmetupdate(struct xrdp_rdp *self, struct stream *s,
     return 0;
 }
 
+ /*****************************************************************************/
+static int APP_CC
+xrdp_caps_process_frame_ack(struct xrdp_rdp *self, struct stream *s, int len)
+{
+    g_writeln("xrdp_caps_process_frame_ack:");
+    self->client_info.use_frame_acks = 1;
+    in_uint32_le(s, self->client_info.max_unacknowledged_frame_count);
+    g_writeln("  max_unacknowledged_frame_count %d", self->client_info.max_unacknowledged_frame_count);
+    return 0;
+}
+
 /*****************************************************************************/
 int APP_CC
 xrdp_caps_process_confirm_active(struct xrdp_rdp *self, struct stream *s)
@@ -626,6 +646,9 @@ xrdp_caps_process_confirm_active(struct xrdp_rdp *self, struct stream *s)
             case RDP_CAPSET_BMPCODECS: /* 0x1d(29) */
                 xrdp_caps_process_codecs(self, s, len);
                 break;
+            case 0x001E: /* CAPSSETTYPE_FRAME_ACKNOWLEDGE */
+                xrdp_caps_process_frame_ack(self, s, len);
+                break;
             default:
                 g_writeln("unknown in xrdp_caps_process_confirm_active %d", type);
                 break;
@@ -880,6 +903,12 @@ xrdp_caps_send_demand_active(struct xrdp_rdp *self)
         out_uint32_le(s, 3 * 1024 * 1024); /* 3MB */
     }
 
+    /* frame acks */
+    caps_count++;
+    out_uint16_le(s, 0x001E); /* CAPSETTYPE_FRAME_ACKNOWLEDGE */
+    out_uint16_le(s, 8);
+    out_uint32_le(s, 2); /* 2 frames in flight */
+
     out_uint8s(s, 4); /* pad */
 
     s_mark_end(s);
diff --git a/libxrdp/xrdp_fastpath.c b/libxrdp/xrdp_fastpath.c
index 6a4eb78e..5bf63b29 100644
--- a/libxrdp/xrdp_fastpath.c
+++ b/libxrdp/xrdp_fastpath.c
@@ -112,18 +112,6 @@ xrdp_fastpath_init(struct xrdp_fastpath *self, struct stream *s)
     return 0;
 }
 
-/*****************************************************************************/
-/* no fragmenation */
-int APP_CC
-xrdp_fastpath_send(struct xrdp_fastpath *self, struct stream *s)
-{
-    if (trans_force_write_s(self->trans, s) != 0)
-    {
-        return 1;
-    }
-    return 0;
-}
-
 /*****************************************************************************/
 static int APP_CC
 xrdp_fastpath_session_callback(struct xrdp_fastpath *self, int msg,
@@ -144,6 +132,19 @@ xrdp_fastpath_session_callback(struct xrdp_fastpath *self, int msg,
     return 0;
 }
 
+/*****************************************************************************/
+/* no fragmenation */
+int APP_CC
+xrdp_fastpath_send(struct xrdp_fastpath *self, struct stream *s)
+{
+    if (trans_force_write_s(self->trans, s) != 0)
+    {
+        return 1;
+    }
+    xrdp_fastpath_session_callback(self, 0x5556, 0, 0, 0, 0);
+    return 0;
+}
+
 /*****************************************************************************/
 /* FASTPATH_INPUT_EVENT_SCANCODE */
 static int APP_CC
diff --git a/libxrdp/xrdp_rdp.c b/libxrdp/xrdp_rdp.c
index 34842533..72562022 100644
--- a/libxrdp/xrdp_rdp.c
+++ b/libxrdp/xrdp_rdp.c
@@ -1106,6 +1106,24 @@ xrdp_rdp_send_disconnect_reason(struct xrdp_rdp *self, int reason)
 }
 #endif
 
+/*****************************************************************************/
+static int APP_CC
+xrdp_rdp_process_frame_ack(struct xrdp_rdp *self, struct stream *s)
+{
+    int frame_id;
+
+    //g_writeln("xrdp_rdp_process_frame_ack:");
+    in_uint32_le(s, frame_id);
+    //g_writeln("  frame_id %d", frame_id);
+    if (self->session->callback != 0)
+    {
+        /* call to xrdp_wm.c : callback */
+        self->session->callback(self->session->id, 0x5557, frame_id, 0,
+                                0, 0);
+    }
+    return 0;
+}
+
 /*****************************************************************************/
 /* RDP_PDU_DATA */
 int APP_CC
@@ -1155,6 +1173,9 @@ xrdp_rdp_process_data(struct xrdp_rdp *self, struct stream *s)
         case RDP_DATA_PDU_FONT2: /* 39(0x27) */
             xrdp_rdp_process_data_font(self, s);
             break;
+        case 56: /* PDUTYPE2_FRAME_ACKNOWLEDGE 0x38 */
+            xrdp_rdp_process_frame_ack(self, s);
+            break;
         default:
             g_writeln("unknown in xrdp_rdp_process_data %d", data_type);
             break;
diff --git a/xrdp/xrdp.h b/xrdp/xrdp.h
index 67488a60..b23cdaf0 100644
--- a/xrdp/xrdp.h
+++ b/xrdp/xrdp.h
@@ -378,6 +378,8 @@ xrdp_mm_get_wait_objs(struct xrdp_mm* self,
                       tbus* read_objs, int* rcount,
                       tbus* write_objs, int* wcount, int* timeout);
 int APP_CC
+xrdp_mm_check_chan(struct xrdp_mm *self);
+int APP_CC
 xrdp_mm_check_wait_objs(struct xrdp_mm* self);
 int DEFAULT_CC
 server_begin_update(struct xrdp_mod* mod);
diff --git a/xrdp/xrdp_encoder.c b/xrdp/xrdp_encoder.c
index 78d1b52e..2b96d803 100644
--- a/xrdp/xrdp_encoder.c
+++ b/xrdp/xrdp_encoder.c
@@ -39,30 +39,76 @@
   } \
   while (0)
 
-#define JPG_CODEC 0
-#define RFX_CODEC 1
-
 /*****************************************************************************/
 static int
-process_enc_jpg(struct xrdp_mm *self, XRDP_ENC_DATA *enc);
+process_enc_jpg(struct xrdp_encoder *self, XRDP_ENC_DATA *enc);
+static int
+process_enc_rfx(struct xrdp_encoder *self, XRDP_ENC_DATA *enc);
 static int
-process_enc_rfx(struct xrdp_mm *self, XRDP_ENC_DATA *enc);
+process_enc_h264(struct xrdp_encoder *self, XRDP_ENC_DATA *enc);
 
-/**
- * Init encoder
- *
- * @return 0 on success, -1 on failure
- *****************************************************************************/
-/* called from main thread */
-int APP_CC
-init_xrdp_encoder(struct xrdp_mm *self)
+/*****************************************************************************/
+struct xrdp_encoder *APP_CC
+xrdp_encoder_create(struct xrdp_mm *mm)
 {
+    struct xrdp_encoder *self;
     char buf[1024];
     int pid;
 
-    if (self == 0)
+    if (mm->wm->client_info->mcs_connection_type != 6) /* LAN */
+    {
+        return 0;
+    }
+
+    if (mm->wm->client_info->bpp < 24)
     {
-        return -1;
+        return 0;
+    }
+
+    self = (struct xrdp_encoder *)g_malloc(sizeof(struct xrdp_encoder), 1);
+    self->mm = mm;
+
+    if (mm->wm->client_info->jpeg_codec_id != 0)
+    {
+        LLOGLN(0, ("xrdp_encoder_create: starting jpeg codec session"));
+        self->codec_id = mm->wm->client_info->jpeg_codec_id;
+        self->in_codec_mode = 1;
+        self->codec_quality = mm->wm->client_info->jpeg_prop[0];
+        mm->wm->client_info->capture_code = 0;
+        mm->wm->client_info->capture_format =
+            /* XRDP_a8b8g8r8 */
+            (32 << 24) | (3 << 16) | (8 << 12) | (8 << 8) | (8 << 4) | 8;
+        self->process_enc = process_enc_jpg;
+    }
+    else if (mm->wm->client_info->rfx_codec_id != 0)
+    {
+        LLOGLN(0, ("xrdp_encoder_create: starting rfx codec session"));
+        self->codec_id = mm->wm->client_info->rfx_codec_id;
+        self->in_codec_mode = 1;
+        mm->wm->client_info->capture_code = 2;
+        self->process_enc = process_enc_rfx;
+#ifdef XRDP_RFXCODEC
+        self->codec_handle =
+            rfxcodec_encode_create(mm->wm->screen->width,
+                                   mm->wm->screen->height,
+                                   RFX_FORMAT_YUV, 0);
+#endif
+    }
+    else if (mm->wm->client_info->h264_codec_id != 0)
+    {
+        LLOGLN(0, ("xrdp_encoder_create: starting h264 codec session"));
+        self->codec_id = mm->wm->client_info->h264_codec_id;
+        self->in_codec_mode = 1;
+        mm->wm->client_info->capture_code = 3;
+        mm->wm->client_info->capture_format =
+            /* XRDP_nv12 */
+            (12 << 24) | (64 << 16) | (0 << 12) | (0 << 8) | (0 << 4) | 0;
+        self->process_enc = process_enc_h264;
+    }
+    else
+    {
+        g_free(self);
+        return 0;
     }
 
     LLOGLN(0, ("init_xrdp_encoder: initing encoder codec_id %d", self->codec_id));
@@ -81,52 +127,25 @@ init_xrdp_encoder(struct xrdp_mm *self)
     g_snprintf(buf, 1024, "xrdp_%8.8x_encoder_term", pid);
     self->xrdp_encoder_term = g_create_wait_obj(buf);
 
-    switch (self->codec_id)
-    {
-        case 2:
-            self->process_enc = process_enc_jpg;
-            break;
-        case 3:
-            self->process_enc = process_enc_rfx;
-#ifdef XRDP_RFXCODEC
-            self->codec_handle =
-                    rfxcodec_encode_create(self->wm->screen->width,
-                                           self->wm->screen->height,
-                                           RFX_FORMAT_YUV, 0);
-                                           //RFX_FORMAT_BGRA, 0);
-#endif
-            break;
-        default:
-            LLOGLN(0, ("init_xrdp_encoder: unknown codec_id %d",
-                   self->codec_id));
-            break;
-
-    }
-
     /* create thread to process messages */
     tc_thread_create(proc_enc_msg, self);
 
-    return 0;
+    return self;
 }
 
-/**
- * Deinit xrdp encoder
- *****************************************************************************/
-/* called from main thread */
+/*****************************************************************************/
 void APP_CC
-deinit_xrdp_encoder(struct xrdp_mm *self)
+xrdp_encoder_delete(struct xrdp_encoder *self)
 {
     XRDP_ENC_DATA *enc;
     XRDP_ENC_DATA_DONE *enc_done;
-    FIFO          *fifo;
-
-    LLOGLN(0, ("deinit_xrdp_encoder: deiniting encoder"));
+    FIFO *fifo;
 
+    LLOGLN(0, ("xrdp_encoder_delete:"));
     if (self == 0)
     {
         return;
     }
-
     if (self->in_codec_mode == 0)
     {
         return;
@@ -135,12 +154,7 @@ deinit_xrdp_encoder(struct xrdp_mm *self)
     g_set_wait_obj(self->xrdp_encoder_term);
     g_sleep(1000);
 
-    if (self->codec_id == 3)
-    {
-#ifdef XRDP_RFXCODEC
-        rfxcodec_encode_destroy(self->codec_handle);
-#endif
-    }
+    /* todo delete specific encoder */
 
     /* destroy wait objects used for signalling */
     g_delete_wait_obj(self->xrdp_encoder_event_to_proc);
@@ -162,7 +176,6 @@ deinit_xrdp_encoder(struct xrdp_mm *self)
             g_free(enc->crects);
             g_free(enc);
         }
-
         fifo_delete(fifo);
     }
 
@@ -173,7 +186,7 @@ deinit_xrdp_encoder(struct xrdp_mm *self)
         while (!fifo_is_empty(fifo))
         {
             enc_done = fifo_remove_item(fifo);
-            if (enc == 0)
+            if (enc_done == 0)
             {
                 continue;
             }
@@ -182,27 +195,28 @@ deinit_xrdp_encoder(struct xrdp_mm *self)
         }
         fifo_delete(fifo);
     }
+    g_free(self);
 }
 
 /*****************************************************************************/
 /* called from encoder thread */
 static int
-process_enc_jpg(struct xrdp_mm *self, XRDP_ENC_DATA *enc)
+process_enc_jpg(struct xrdp_encoder *self, XRDP_ENC_DATA *enc)
 {
-    int                  index;
-    int                  x;
-    int                  y;
-    int                  cx;
-    int                  cy;
-    int                  quality;
-    int                  error;
-    int                  out_data_bytes;
-    int                  count;
-    char                *out_data;
-    XRDP_ENC_DATA_DONE  *enc_done;
-    FIFO                *fifo_processed;
-    tbus                 mutex;
-    tbus                 event_processed;
+    int index;
+    int x;
+    int y;
+    int cx;
+    int cy;
+    int quality;
+    int error;
+    int out_data_bytes;
+    int count;
+    char *out_data;
+    XRDP_ENC_DATA_DONE *enc_done;
+    FIFO *fifo_processed;
+    tbus mutex;
+    tbus event_processed;
 
     LLOGLN(10, ("process_enc_jpg:"));
     quality = self->codec_quality;
@@ -236,9 +250,10 @@ process_enc_jpg(struct xrdp_mm *self, XRDP_ENC_DATA *enc)
             LLOGLN(0, ("process_enc_jpg: error 3"));
             return 1;
         }
+
         out_data[256] = 0; /* header bytes */
         out_data[257] = 0;
-        error = libxrdp_codec_jpeg_compress(self->wm->session, 0, enc->data,
+        error = libxrdp_codec_jpeg_compress(self->mm->wm->session, 0, enc->data,
                                             enc->width, enc->height,
                                             enc->width * 4, x, y, cx, cy,
                                             quality,
@@ -278,7 +293,7 @@ process_enc_jpg(struct xrdp_mm *self, XRDP_ENC_DATA *enc)
 /*****************************************************************************/
 /* called from encoder thread */
 static int
-process_enc_rfx(struct xrdp_mm *self, XRDP_ENC_DATA *enc)
+process_enc_rfx(struct xrdp_encoder *self, XRDP_ENC_DATA *enc)
 {
     int index;
     int x;
@@ -364,8 +379,8 @@ process_enc_rfx(struct xrdp_mm *self, XRDP_ENC_DATA *enc)
     enc_done->comp_pad_data = out_data;
     enc_done->enc = enc;
     enc_done->last = 1;
-    enc_done->cx = self->wm->screen->width;
-    enc_done->cy = self->wm->screen->height;
+    enc_done->cx = self->mm->wm->screen->width;
+    enc_done->cy = self->mm->wm->screen->height;
 
     /* done with msg */
     /* inform main thread done */
@@ -383,36 +398,45 @@ process_enc_rfx(struct xrdp_mm *self, XRDP_ENC_DATA *enc)
 /*****************************************************************************/
 /* called from encoder thread */
 static int
-process_enc_rfx(struct xrdp_mm *self, XRDP_ENC_DATA *enc)
+process_enc_rfx(struct xrdp_encoder *self, XRDP_ENC_DATA *enc)
 {
     return 0;
 }
 
 #endif
 
+/*****************************************************************************/
+/* called from encoder thread */
+static int
+process_enc_h264(struct xrdp_encoder *self, XRDP_ENC_DATA *enc)
+{
+    LLOGLN(0, ("process_enc_x264:"));
+    return 0;
+}
+
 /**
  * Encoder thread main loop
  *****************************************************************************/
 THREAD_RV THREAD_CC
 proc_enc_msg(void *arg)
 {
-    XRDP_ENC_DATA  *enc;
-    FIFO           *fifo_to_proc;
-    tbus            mutex;
-    tbus            event_to_proc;
-    tbus            term_obj;
-    tbus            lterm_obj;
-    int             robjs_count;
-    int             wobjs_count;
-    int             cont;
-    int             timeout;
-    tbus            robjs[32];
-    tbus            wobjs[32];
-    struct xrdp_mm *self;
+    XRDP_ENC_DATA *enc;
+    FIFO *fifo_to_proc;
+    tbus mutex;
+    tbus event_to_proc;
+    tbus term_obj;
+    tbus lterm_obj;
+    int robjs_count;
+    int wobjs_count;
+    int cont;
+    int timeout;
+    tbus robjs[32];
+    tbus wobjs[32];
+    struct xrdp_encoder *self;
 
     LLOGLN(0, ("proc_enc_msg: thread is running"));
 
-    self = (struct xrdp_mm *) arg;
+    self = (struct xrdp_encoder *) arg;
     if (self == 0)
     {
         LLOGLN(0, ("proc_enc_msg: self nil"));
diff --git a/xrdp/xrdp_encoder.h b/xrdp/xrdp_encoder.h
index 1d525f12..f138d749 100644
--- a/xrdp/xrdp_encoder.h
+++ b/xrdp/xrdp_encoder.h
@@ -3,13 +3,67 @@
 #define _XRDP_ENCODER_H
 
 #include "arch.h"
+#include "fifo.h"
 
-struct xrdp_mm;
+struct xrdp_enc_data;
 
-int APP_CC
-init_xrdp_encoder(struct xrdp_mm *self);
+/* for codec mode operations */
+struct xrdp_encoder
+{
+    struct xrdp_mm *mm;
+    int in_codec_mode;
+    int codec_id;
+    int codec_quality;
+    tbus xrdp_encoder_event_to_proc;
+    tbus xrdp_encoder_event_processed;
+    tbus xrdp_encoder_term;
+    FIFO *fifo_to_proc;
+    FIFO *fifo_processed;
+    tbus mutex;
+    int (*process_enc)(struct xrdp_encoder *self, struct xrdp_enc_data *enc);
+    void *codec_handle;
+    int frame_id_client; /* last frame id received from client */
+    int frame_id_server; /* last frame id received from Xorg */
+    int frame_id_server_sent;
+};
+
+/* used when scheduling tasks in xrdp_encoder.c */
+struct xrdp_enc_data
+{
+    struct xrdp_mod *mod;
+    int num_drects;
+    short *drects;     /* 4 * num_drects */
+    int num_crects;
+    short *crects;     /* 4 * num_crects */
+    char *data;
+    int width;
+    int height;
+    int flags;
+    int frame_id;
+};
+
+typedef struct xrdp_enc_data XRDP_ENC_DATA;
+
+/* used when scheduling tasks from xrdp_encoder.c */
+struct xrdp_enc_data_done
+{
+    int comp_bytes;
+    int pad_bytes;
+    char *comp_pad_data;
+    struct xrdp_enc_data *enc;
+    int last; /* true is this is last message for enc */
+    int x;
+    int y;
+    int cx;
+    int cy;
+};
+
+typedef struct xrdp_enc_data_done XRDP_ENC_DATA_DONE;
+
+struct xrdp_encoder *APP_CC
+xrdp_encoder_create(struct xrdp_mm *mm);
 void APP_CC
-deinit_xrdp_encoder(struct xrdp_mm *self);
+xrdp_encoder_delete(struct xrdp_encoder *self);
 THREAD_RV THREAD_CC
 proc_enc_msg(void *arg);
 
diff --git a/xrdp/xrdp_mm.c b/xrdp/xrdp_mm.c
index 76957ad6..8d67016b 100644
--- a/xrdp/xrdp_mm.c
+++ b/xrdp/xrdp_mm.c
@@ -58,46 +58,16 @@ xrdp_mm_create(struct xrdp_wm *owner)
     self->login_values->auto_free = 1;
 
     LLOGLN(0, ("xrdp_mm_create: bpp %d mcs_connection_type %d "
-           "jpeg_codec_id %d v3_codec_id %d rfx_codec_id %d",
+           "jpeg_codec_id %d v3_codec_id %d rfx_codec_id %d "
+           "h264_codec_id %d",
            self->wm->client_info->bpp,
            self->wm->client_info->mcs_connection_type,
            self->wm->client_info->jpeg_codec_id,
            self->wm->client_info->v3_codec_id,
-           self->wm->client_info->rfx_codec_id));
-    /* go into jpeg codec mode if jpeg set, lan set */
-    if (self->wm->client_info->mcs_connection_type == 6) /* LAN */
-    {
-        if (self->wm->client_info->jpeg_codec_id == 2) /* JPEG */
-        {
-            if (self->wm->client_info->bpp > 16)
-            {
-                LLOGLN(0, ("xrdp_mm_create: starting jpeg codec session"));
-                self->codec_id = 2;
-                self->in_codec_mode = 1;
-                self->codec_quality = self->wm->client_info->jpeg_prop[0];
-                self->wm->client_info->capture_code = 0;
-                self->wm->client_info->capture_format =
-                /* PIXMAN_a8b8g8r8 */
-                (32 << 24) | (3 << 16) | (8 << 12) | (8 << 8) | (8 << 4) | 8;
-            }
-        }
-        else if (self->wm->client_info->rfx_codec_id == 3) /* RFX */
-        {
-            if (self->wm->client_info->bpp > 16)
-            {
-                LLOGLN(0, ("xrdp_mm_create: starting rfx codec session"));
-                self->codec_id = 3;
-                self->in_codec_mode = 1;
-                self->wm->client_info->capture_code = 2;
-            }
-        }
-    }
+           self->wm->client_info->rfx_codec_id,
+           self->wm->client_info->h264_codec_id));
 
-    if (self->in_codec_mode)
-    {
-    /* setup thread to handle codec mode messages */
-        init_xrdp_encoder(self);
-    }
+    self->encoder = xrdp_encoder_create(self);
 
     return self;
 }
@@ -174,7 +144,7 @@ xrdp_mm_delete(struct xrdp_mm *self)
     xrdp_mm_module_cleanup(self);
 
     /* shutdown thread */
-    deinit_xrdp_encoder(self);
+    xrdp_encoder_delete(self->encoder);
 
     trans_delete(self->sesman_trans);
     self->sesman_trans = 0;
@@ -1956,9 +1926,9 @@ xrdp_mm_get_wait_objs(struct xrdp_mm *self,
         }
     }
 
-    if (self->in_codec_mode)
+    if (self->encoder != 0)
     {
-        read_objs[(*rcount)++] = self->xrdp_encoder_event_processed;
+        read_objs[(*rcount)++] = self->encoder->xrdp_encoder_event_processed;
     }
 
     return rv;
@@ -2019,6 +1989,28 @@ xrdp_mm_dump_jpeg(struct xrdp_mm *self, XRDP_ENC_DATA_DONE *enc_done)
 
 #endif
 
+/*****************************************************************************/
+int APP_CC
+xrdp_mm_check_chan(struct xrdp_mm *self)
+{
+    //g_writeln("xrdp_mm_check_chan:");
+    if ((self->chan_trans != 0) && self->chan_trans_up)
+    {
+        if (trans_check_wait_objs(self->chan_trans) != 0)
+        {
+            self->delete_chan_trans = 1;
+        }
+    }
+    if (self->delete_chan_trans)
+    {
+        trans_delete(self->chan_trans);
+        self->chan_trans = 0;
+        self->chan_trans_up = 0;
+        self->delete_chan_trans = 0;
+    }
+    return 0;
+}
+
 /*****************************************************************************/
 int APP_CC
 xrdp_mm_check_wait_objs(struct xrdp_mm *self)
@@ -2029,6 +2021,8 @@ xrdp_mm_check_wait_objs(struct xrdp_mm *self)
     int y;
     int cx;
     int cy;
+    int use_frame_acks;
+    int ex;
 
     if (self == 0)
     {
@@ -2077,15 +2071,18 @@ xrdp_mm_check_wait_objs(struct xrdp_mm *self)
         self->delete_chan_trans = 0;
     }
 
-    if (self->in_codec_mode)
+    if (self->encoder != 0)
     {
-        if (g_is_wait_obj_set(self->xrdp_encoder_event_processed))
+
+        use_frame_acks = self->wm->client_info->use_frame_acks;
+
+        if (g_is_wait_obj_set(self->encoder->xrdp_encoder_event_processed))
         {
-            g_reset_wait_obj(self->xrdp_encoder_event_processed);
-            tc_mutex_lock(self->mutex);
+            g_reset_wait_obj(self->encoder->xrdp_encoder_event_processed);
+            tc_mutex_lock(self->encoder->mutex);
             enc_done = (XRDP_ENC_DATA_DONE*)
-                       fifo_remove_item(self->fifo_processed);
-            tc_mutex_unlock(self->mutex);
+                       fifo_remove_item(self->encoder->fifo_processed);
+            tc_mutex_unlock(self->encoder->mutex);
             while (enc_done != 0)
             {
                 /* do something with msg */
@@ -2103,36 +2100,85 @@ xrdp_mm_check_wait_objs(struct xrdp_mm *self)
 
                 if (enc_done->comp_bytes > 0)
                 {
+                    libxrdp_fastpath_send_frame_marker(self->wm->session, 0,
+                                                       enc_done->enc->frame_id);
                     libxrdp_fastpath_send_surface(self->wm->session,
                                                   enc_done->comp_pad_data,
                                                   enc_done->pad_bytes,
                                                   enc_done->comp_bytes,
                                                   x, y, x + cx, y + cy,
-                                                  32, self->codec_id, cx, cy);
+                                                  32, self->encoder->codec_id, cx, cy);
+                    libxrdp_fastpath_send_frame_marker(self->wm->session, 1,
+                                                       enc_done->enc->frame_id);
                 }
 
                 /* free enc_done */
                 if (enc_done->last)
                 {
                     LLOGLN(10, ("xrdp_mm_check_wait_objs: last set"));
-                           self->mod->mod_frame_ack(self->mod,
-                           enc_done->enc->flags, enc_done->enc->frame_id);
+                    if (use_frame_acks == 0)
+                    {
+                        self->mod->mod_frame_ack(self->mod,
+                                                 enc_done->enc->flags,
+                                                 enc_done->enc->frame_id);
+                    }
+                    else
+                    {
+#if 1
+                        ex = self->wm->client_info->max_unacknowledged_frame_count;
+                        if (self->encoder->frame_id_client + ex > self->encoder->frame_id_server)
+                        {
+                            if (self->encoder->frame_id_server > self->encoder->frame_id_server_sent)
+                            {
+                                LLOGLN(10, ("xrdp_mm_check_wait_objs: 1 -- %d", self->encoder->frame_id_server));
+                                self->encoder->frame_id_server_sent = self->encoder->frame_id_server;
+                                self->mod->mod_frame_ack(self->mod, 0, self->encoder->frame_id_server);
+                            }
+                        }
+#endif
+                    }
                     g_free(enc_done->enc->drects);
                     g_free(enc_done->enc->crects);
                     g_free(enc_done->enc);
                 }
                 g_free(enc_done->comp_pad_data);
                 g_free(enc_done);
-                tc_mutex_lock(self->mutex);
+                tc_mutex_lock(self->encoder->mutex);
                 enc_done = (XRDP_ENC_DATA_DONE*)
-                           fifo_remove_item(self->fifo_processed);
-                tc_mutex_unlock(self->mutex);
+                           fifo_remove_item(self->encoder->fifo_processed);
+                tc_mutex_unlock(self->encoder->mutex);
             }
         }
     }
     return rv;
 }
 
+/*****************************************************************************/
+/* frame ack from client */
+int APP_CC
+xrdp_mm_frame_ack(struct xrdp_mm *self, int frame_id)
+{
+    int ex;
+
+    LLOGLN(0, ("xrdp_mm_frame_ack:"));
+    self->encoder->frame_id_client = frame_id;
+    if (self->wm->client_info->use_frame_acks == 0)
+    {
+        return 1;
+    }
+    ex = self->wm->client_info->max_unacknowledged_frame_count;
+    if (self->encoder->frame_id_client + ex > self->encoder->frame_id_server)
+    {
+        if (self->encoder->frame_id_server > self->encoder->frame_id_server_sent)
+        {
+            LLOGLN(10, ("xrdp_mm_frame_ack: frame_id_server %d", self->encoder->frame_id_server));
+            self->encoder->frame_id_server_sent = self->encoder->frame_id_server;
+            self->mod->mod_frame_ack(self->mod, 0, self->encoder->frame_id_server);
+        }
+    }
+    return 0;
+}
+
 #if 0
 /*****************************************************************************/
 struct xrdp_painter *APP_CC
@@ -2354,9 +2400,9 @@ server_paint_rects(struct xrdp_mod* mod, int num_drects, short *drects,
     mm = wm->mm;
 
     LLOGLN(10, ("server_paint_rects:"));
-    LLOGLN(10, ("server_paint_rects: %d", mm->in_codec_mode));
+    LLOGLN(10, ("server_paint_rects: %p", mm->encoder));
 
-    if (mm->in_codec_mode)
+    if (mm->encoder != 0)
     {
         /* copy formal params to XRDP_ENC_DATA */
         enc_data = (XRDP_ENC_DATA *) g_malloc(sizeof(XRDP_ENC_DATA), 1);
@@ -2393,18 +2439,19 @@ server_paint_rects(struct xrdp_mod* mod, int num_drects, short *drects,
         enc_data->height = height;
         enc_data->flags = flags;
         enc_data->frame_id = frame_id;
+        mm->encoder->frame_id_server = frame_id;
         if (width == 0 || height == 0)
         {
             LLOGLN(10, ("server_paint_rects: error"));
         }
 
         /* insert into fifo for encoder thread to process */
-        tc_mutex_lock(mm->mutex);
-        fifo_add_item(mm->fifo_to_proc, (void *) enc_data);
-        tc_mutex_unlock(mm->mutex);
+        tc_mutex_lock(mm->encoder->mutex);
+        fifo_add_item(mm->encoder->fifo_to_proc, (void *) enc_data);
+        tc_mutex_unlock(mm->encoder->mutex);
 
         /* signal xrdp_encoder thread */
-        g_set_wait_obj(mm->xrdp_encoder_event_to_proc);
+        g_set_wait_obj(mm->encoder->xrdp_encoder_event_to_proc);
 
         return 0;
     }
diff --git a/xrdp/xrdp_types.h b/xrdp/xrdp_types.h
index 29aaac84..21d00e9a 100644
--- a/xrdp/xrdp_types.h
+++ b/xrdp/xrdp_types.h
@@ -292,19 +292,7 @@ struct xrdp_mm
   int chan_trans_up; /* true once connected to chansrv */
   int delete_chan_trans; /* boolean set when done with channel connection */
   int usechansrv; /* true if chansrvport is set in xrdp.ini or using sesman */
-
-  /* for codec mode operations */
-  int   in_codec_mode;
-  int   codec_id;
-  int   codec_quality;
-  tbus  xrdp_encoder_event_to_proc;
-  tbus  xrdp_encoder_event_processed;
-  tbus  xrdp_encoder_term;
-  FIFO *fifo_to_proc;
-  FIFO *fifo_processed;
-  tbus  mutex;
-  int (*process_enc)(struct xrdp_mm *self, struct xrdp_enc_data *enc);
-  void *codec_handle;
+  struct xrdp_encoder *encoder;
 };
 
 struct xrdp_key_info
@@ -624,39 +612,4 @@ struct xrdp_config
     struct xrdp_cfg_channels  cfg_channels;
 };
 
-/* used when scheduling tasks in xrdp_encoder.c */
-struct xrdp_enc_data
-{
-    struct xrdp_mod *mod;
-    int              num_drects;
-    short           *drects;     /* 4 * num_drects */
-    int              num_crects;
-    short           *crects;     /* 4 * num_crects */
-    char            *data;
-    int              width;
-    int              height;
-    int              flags;
-    int              frame_id;
-};
-
-typedef struct xrdp_enc_data XRDP_ENC_DATA;
-
-/* used when scheduling tasks from xrdp_encoder.c */
-struct xrdp_enc_data_done
-{
-    int                   comp_bytes;
-    int                   pad_bytes;
-    char                 *comp_pad_data;
-    struct xrdp_enc_data *enc;
-    int                   last; /* true is this is last message for enc */
-    int                   x;
-    int                   y;
-    int                   cx;
-    int                   cy;
-};
-
-typedef struct xrdp_enc_data_done XRDP_ENC_DATA_DONE;
-
-
-
 #endif
diff --git a/xrdp/xrdp_wm.c b/xrdp/xrdp_wm.c
index 591c8a51..e3af0f05 100644
--- a/xrdp/xrdp_wm.c
+++ b/xrdp/xrdp_wm.c
@@ -1733,8 +1733,14 @@ callback(long id, int msg, long param1, long param2, long param3, long param4)
                     pass it to module if there is one */
             rv = xrdp_wm_process_channel_data(wm, param1, param2, param3, param4);
             break;
+        case 0x5556:
+            rv = xrdp_mm_check_chan(wm->mm);
+            break;
+        case 0x5557:
+            //g_writeln("callback: frame ack %d", param1);
+            xrdp_mm_frame_ack(wm->mm, param1);
+            break;
     }
-
     return rv;
 }