Add: GStreamer plugin 8331 input support (#1159)

Add support for 8331 adjacent ancillary data
input for the GStreamer st40 ancillary data plugin.
Which allows the user to take input from 

https://www.[ietf.org/rfc/rfc8331.html](https://www.ietf.org/rfc/rfc8331.html)
Starting ANC_Count  and ending with word_align.

Add support for buffer size for UDW support
that allows the user to change the size of the
buffers, set it to the maximum by default 
as the wasted size of appropriately 
2kb * framebuffer count is acceptable.

Change the st40p api to hide the metadata,
which should be clearer for users. 

Refactor: Isolate the parsing of data into
gst_mtl_st40p_tx_parse_*  functions.

Fix the issue with the GST buffer size being taken from
the whole GstBuffer instead of the mapped
GstMemory.

Author: DawidWesierski4

ecosystem/gstreamer_plugin/README.md

@@ -395,14 +395,19 @@ The `mtl_st40p_tx` plugin supports all pad capabilities (the data is not checked
 - **Capabilities**: Any (GST_STATIC_CAPS_ANY)
 
 **Arguments**
-| Property Name      | Type     | Description                                                        | Range         | Default Value |
-|--------------------|----------|--------------------------------------------------------------------|---------------|---------------|
-| tx-framebuff-cnt   | uint     | Number of framebuffers to be used for transmission.                | 0 to G_MAXUINT| 3             |
-| tx-fps             | uint     | Framerate of the video to which the ancillary data is synchronized.| [Supported video fps fractions](#231-supported-video-fps-fractions) | 25/1 |
-| tx-did             | uint     | Data ID for the ancillary data.                                    | 0 to 255      | 0             |
-| tx-sdid            | uint     | Secondary Data ID for the ancillary data.                          | 0 to 255      | 0             |
-| use-pts-for-pacing | gboolean | [User controlled timestamping offset](#233-pts-controlled-pacing)  | 0 to G_MAXUINT | 0            |
-| pts-pacing-offset  | uint     | [User controlled timestamping offset](#233-pts-controlled-pacing)  | 0 to G_MAXUINT | 0            |
+| Property Name         | Type     | Description                                                        | Range            | Default Value |
+|-----------------------|----------|--------------------------------------------------------------------|------------------|---------------|
+| tx-framebuff-cnt      | uint     | Number of framebuffers to be used for transmission.                | 0 to G_MAXUINT   | 3             |
+| tx-fps                | uint     | Framerate of the video to which the ancillary data is synchronized.| [Supported vid eo fps fractions](#231-supported-video-fps-fractions) | 25/1 |
+| tx-did                | uint     | Data ID for the ancillary data.                                    | 0 to 255         | 0             |
+| tx-sdid               | uint     | Secondary Data ID for the ancillary data.                          | 0 to 255         | 0             |
+| use-pts-for-pacing    | gboolean | [User controlled timestamping offset](#233-pts-controlled-pacing)  | TRUE/FALSE       | FALSE         |
+| pts-pacing-offset     | uint     | [User controlled timestamping offset](#233-pts-controlled-pacing)  | 0 to G_MAXUINT   | 0             |
+| parse-8331-meta       | gboolean | Treat the input as rfc8331 payload data                            | TRUE/FALSE       | FALSE         |
+| max-combined-udw-size | uint     | Maximum combined size of all user data words to send in one buffer | 0 to (20 * 255)  | 20 * 255      |
+
+> **Note:**  
+> If `parse-8331-meta` is not enabled, only one ANC packet per frame is supported. It is recommended to limit the `max-combined-udw-size` if you are only using this option, since by default `max-combined-udw-size` is set to its maximum value.
 
 #### 5.1.2. Example GStreamer Pipeline for Transmission
 

ecosystem/gstreamer_plugin/gst_mtl_st20p_tx.c

@@ -507,7 +507,7 @@ static GstFlowReturn gst_mtl_st20p_tx_chain(GstPad* pad, GstObject* parent,
       frame->tfmt = ST10_TIMESTAMP_FMT_TAI;
     }
 
-    mtl_memcpy(frame->addr[0], map_info.data, buffer_size);
+    memcpy(frame->addr[0], map_info.data, buffer_size);
     gst_memory_unmap(gst_buffer_memory, &map_info);
     st20p_tx_put_frame(sink->tx_handle, frame);
   }

ecosystem/gstreamer_plugin/gst_mtl_st30p_tx.c

@@ -546,12 +546,12 @@ static GstFlowReturn gst_mtl_st30p_tx_chain(GstPad* pad, GstObject* parent,
       cur_addr_buf = map_info.data + gst_buffer_get_size(buf) - bytes_to_write;
 
       if (sink->cur_frame_available_size > bytes_to_write) {
-        mtl_memcpy(cur_addr_frame, cur_addr_buf, bytes_to_write);
+        memcpy(cur_addr_frame, cur_addr_buf, bytes_to_write);
         sink->cur_frame_available_size -= bytes_to_write;
         bytes_to_write = 0;
         break;
       } else {
-        mtl_memcpy(cur_addr_frame, cur_addr_buf, sink->cur_frame_available_size);
+        memcpy(cur_addr_frame, cur_addr_buf, sink->cur_frame_available_size);
 
         // By default, timestamping is handled by MTL.
         if (sink->use_pts_for_pacing) {

ecosystem/gstreamer_plugin/gst_mtl_st40_rx.c

@@ -375,16 +375,16 @@ static void* gst_mtl_st40_rx_get_mbuf_with_timeout(Gst_Mtl_St40_Rx* src,
 static GstFlowReturn gst_mtl_st40_rx_fill_buffer(Gst_Mtl_St40_Rx* src, GstBuffer** buffer,
                                                  void* usrptr) {
   struct st40_rfc8331_rtp_hdr* hdr;
-  struct st40_rfc8331_payload_hdr* payload_hdr;
+  struct st40_rfc8331_payload_hdr *payload_hdr, payload_hdr_swapped;
   GstMapInfo dest_info;
   guint16 data, fill_size;
   gint udw_size;
 
   hdr = (struct st40_rfc8331_rtp_hdr*)usrptr;
   payload_hdr = (struct st40_rfc8331_payload_hdr*)(&hdr[1]);
-  payload_hdr->swaped_second_hdr_chunk = ntohl(payload_hdr->swaped_second_hdr_chunk);
-  udw_size = payload_hdr->second_hdr_chunk.data_count & 0xff;
-  payload_hdr->swaped_second_hdr_chunk = htonl(payload_hdr->swaped_second_hdr_chunk);
+  payload_hdr_swapped.swapped_second_hdr_chunk =
+      ntohl(payload_hdr->swapped_second_hdr_chunk);
+  udw_size = payload_hdr_swapped.second_hdr_chunk.data_count & 0xff;
 
   if (udw_size == 0) {
     GST_ERROR("Ancillary data size is 0");
@@ -398,6 +398,7 @@ static GstFlowReturn gst_mtl_st40_rx_fill_buffer(Gst_Mtl_St40_Rx* src, GstBuffer
       free(src->anc_data);
       src->anc_data = NULL;
     }
+
     src->udw_size = udw_size;
     src->anc_data = (char*)malloc(udw_size);
   }