From 8056e0eb44f872d39b24255e25f3382e030a9e62 Mon Sep 17 00:00:00 2001
From: "Kolelis, Szymon" <szymon.kolelis@intel.com>
Date: Fri, 6 Sep 2024 10:46:50 +0200
Subject: [PATCH] st41 working for frame and rtp modes

---
 app/src/app_base.h                          |  3 ++
 app/src/args.c                              |  1 +
 app/src/parse_json.c                        | 40 +++++++++++++-----
 app/src/parse_json.h                        |  8 +---
 app/src/rx_fastmetadata_app.c               | 22 +++++++---
 app/src/tx_fastmetadata_app.c               | 33 +++++++++++----
 include/st40_api.h                          |  2 +-
 include/st41_api.h                          | 47 +++++++++++++++++----
 lib/src/st2110/st_fastmetadata.c            |  2 +-
 lib/src/st2110/st_header.h                  |  2 +-
 lib/src/st2110/st_tx_fastmetadata_session.c | 37 ++++++++++------
 11 files changed, 141 insertions(+), 56 deletions(-)

diff --git a/app/src/app_base.h b/app/src/app_base.h
index 10ee856a7..66a4e3e39 100644
--- a/app/src/app_base.h
+++ b/app/src/app_base.h
@@ -247,6 +247,9 @@ struct st_app_tx_fmd_session {
   int st41_source_fd;
   pcap_t* st41_pcap;
   bool st41_pcap_input;
+  uint32_t fmd_dit;
+  uint32_t fmd_k_bit;
+
   bool st41_rtp_input;
   uint8_t* st41_source_begin;
   uint8_t* st41_source_end;
diff --git a/app/src/args.c b/app/src/args.c
index cd5eef182..46392c556 100644
--- a/app/src/args.c
+++ b/app/src/args.c
@@ -358,6 +358,7 @@ static int app_args_json(struct st_app_context* ctx, struct mtl_init_params* p,
     ctx->json_ctx = NULL;
     return ret;
   }
+
   ctx->tx_video_session_cnt = ctx->json_ctx->tx_video_session_cnt;
   ctx->tx_audio_session_cnt = ctx->json_ctx->tx_audio_session_cnt;
   ctx->tx_anc_session_cnt = ctx->json_ctx->tx_anc_session_cnt;
diff --git a/app/src/parse_json.c b/app/src/parse_json.c
index d09c8f3e3..e260b4a2b 100644
--- a/app/src/parse_json.c
+++ b/app/src/parse_json.c
@@ -1229,15 +1229,35 @@ static int st_json_parse_tx_fmd(int idx, json_object* fmd_obj,
     err("%s, invalid fmd type %s\n", __func__, type);
     return -ST_JSON_NOT_VALID;
   }
-  /* parse fmd format */
-  const char* fmd_format =
-      json_object_get_string(st_json_object_object_get(fmd_obj, "fastmetadata_format"));
-  REQUIRED_ITEM(fmd_format);
-  if (strcmp(fmd_format, "closed_caption") == 0) {
-    fmd->info.fmd_format = FMD_FORMAT_CLOSED_CAPTION;
+
+  /* parse fmd data item type */
+  json_object* fmd_dit_obj = st_json_object_object_get(fmd_obj, "fastmetadata_data_item_type");
+  if (fmd_dit_obj) {
+    uint32_t fmd_dit = json_object_get_int(fmd_dit_obj);
+    if (fmd_dit < 0 || fmd_dit > 0x3fffff) {
+      err("%s, invalid fastmetadata_data_item_type 0x%x\n", __func__, fmd_dit);
+      return -ST_JSON_NOT_VALID;
+    }
+    fmd->info.fmd_dit = fmd_dit;
+    info("%s, fastmetadata_data_item_type = 0x%x\n", __func__, fmd_dit);
   } else {
-    err("%s, invalid fmd format %s\n", __func__, fmd_format);
-    return -ST_JSON_NOT_VALID;
+    err("%s, No fastmetadata_data_item_type !\n", __func__);
+    return -ST_JSON_NULL;
+  }
+
+  /* parse fmd data item K-bit */
+  json_object* fmd_k_bit_obj = st_json_object_object_get(fmd_obj, "fastmetadata_k_bit");
+  if (fmd_k_bit_obj) {
+    uint8_t fmd_k_bit = json_object_get_int(fmd_k_bit_obj);
+    if (fmd_k_bit < 0 || fmd_k_bit > 1) {
+      err("%s, invalid fastmetadata_k_bit 0x%x\n", __func__, fmd_k_bit);
+      return -ST_JSON_NOT_VALID;
+    }
+    fmd->info.fmd_k_bit = fmd_k_bit;
+    info("%s, fastmetadata_k_bit = 0x%x\n", __func__, fmd_k_bit);
+  } else {
+    err("%s, No fastmetadata_k_bit !\n", __func__);
+    return -ST_JSON_NULL;
   }
 
   /* parse fmd fps */
@@ -1338,7 +1358,7 @@ static int parse_st22p_fps(json_object* st22p_obj, st_json_st22p_session_t* st22
   } else if (strcmp(fps, "p29") == 0) {
     st22p->info.fps = ST_FPS_P29_97;
   } else {
-    err("%s, invalid anc fps %s\n", __func__, fps); //skolelis tbd: here I dont see corelation for st41(fmd), but why there is st40(anc) actually?
+    err("%s, invalid st22 fps %s\n", __func__, fps);
     return -ST_JSON_NOT_VALID;
   }
   return ST_JSON_SUCCESS;
@@ -1646,7 +1666,7 @@ static int parse_st20p_fps(json_object* st20p_obj, st_json_st20p_session_t* st20
   } else if (strcmp(fps, "p29") == 0) {
     st20p->info.fps = ST_FPS_P29_97;
   } else {
-    err("%s, invalid anc fps %s\n", __func__, fps); //skolelis tbd: here I dont see corelation for st41(fmd), but why there is st40(anc) actually?
+    err("%s, invalid st20 fps %s\n", __func__, fps);
     return -ST_JSON_NOT_VALID;
   }
   return ST_JSON_SUCCESS;
diff --git a/app/src/parse_json.h b/app/src/parse_json.h
index 9b8d449e8..e6283ce29 100644
--- a/app/src/parse_json.h
+++ b/app/src/parse_json.h
@@ -105,11 +105,6 @@ enum anc_format {
   ANC_FORMAT_MAX,
 };
 
-enum fmd_format {
-  FMD_FORMAT_CLOSED_CAPTION,
-  FMD_FORMAT_MAX,
-};  // skolelis tbd: I don't think closed caption is relevant here in st41. The enum to be removed or changed.
-
 struct st_video_fmt_desc {
   enum video_format fmt;
   char* name;
@@ -187,7 +182,8 @@ typedef struct st_json_ancillary_info {
 
 typedef struct st_json_fastmetadata_info {
   enum st41_type type;
-  enum fmd_format fmd_format;
+  uint32_t fmd_dit;
+  uint8_t fmd_k_bit;
   enum st_fps fmd_fps;
   bool interlaced;
 
diff --git a/app/src/rx_fastmetadata_app.c b/app/src/rx_fastmetadata_app.c
index d2bf1238f..eb8ae00bb 100644
--- a/app/src/rx_fastmetadata_app.c
+++ b/app/src/rx_fastmetadata_app.c
@@ -4,15 +4,23 @@
 
 #include "rx_fastmetadata_app.h"
 
-static void app_rx_fmd_handle_rtp(struct st_app_rx_fmd_session* s) { //skolelis tbd remove }, void* usrptr) {
-  // skolelis tbd remove this line struct st41_rtp_hdr* hdr = (struct st41_rtp_hdr*)usrptr;
-  // skolelis tbd remove this line struct st41_rfc8331_payload_hdr* payload_hdr =
-  // skolelis tbd remove this line       (struct st41_rfc8331_payload_hdr*)(&hdr[1]);
+static void app_rx_fmd_handle_rtp(struct st_app_rx_fmd_session* s) { // skolelis tbd: remove }, void* usrptr) {
+  // skolelis tbd: struct st41_rtp_hdr* hdr = (struct st41_rtp_hdr*)usrptr;
+  // skolelis tbd: struct st41_rfc8331_payload_hdr* payload_hdr = (struct st41_rfc8331_payload_hdr*)(&hdr[1]);
+  
   dbg("%s(%d).\n", __func__, s->idx);
 
-  // skolelis what for this nthol() 2x ? payload_hdr->swaped_second_hdr_chunk = ntohl(payload_hdr->swaped_second_hdr_chunk);
-  // skolelis what for this nthol() 2x ? payload_hdr->swaped_second_hdr_chunk = htonl(payload_hdr->swaped_second_hdr_chunk);
+  // skolelis tbd: payload_hdr->swaped_second_hdr_chunk = htonl(payload_hdr->swaped_second_hdr_chunk);
 
+/* // skolelis tbd: some checking should be done. in st40 here we were checking if checksums and parities are correct. 
+   // skolelis tbd: here in st41 we dont have such mechanisms to verify. so what else?
+  if (!st41_check_parity_bits(payload_hdr->second_hdr_chunk.did) ||
+      !st41_check_parity_bits(payload_hdr->second_hdr_chunk.sdid) ||
+      !st41_check_parity_bits(payload_hdr->second_hdr_chunk.data_count)) {
+    err("%s(%d), fmd RTP checkParityBits error\n", __func__, s->idx);
+    return;
+  }
+*/
   s->stat_frame_total_received++;
   if (!s->stat_frame_first_rx_time)
     s->stat_frame_first_rx_time = st_app_get_monotonic_time();
@@ -37,7 +45,7 @@ static void* app_rx_fmd_read_thread(void* arg) {
       continue;
     }
     /* parse the packet */
-    app_rx_fmd_handle_rtp(s); // skolelis tbd remove: , usrptr);
+    app_rx_fmd_handle_rtp(s); // skolelis tbd: remove: , usrptr);
     st41_rx_put_mbuf(s->handle, mbuf);
   }
   info("%s(%d), stop\n", __func__, idx);
diff --git a/app/src/tx_fastmetadata_app.c b/app/src/tx_fastmetadata_app.c
index 9e91b2fc4..f497ebfbe 100644
--- a/app/src/tx_fastmetadata_app.c
+++ b/app/src/tx_fastmetadata_app.c
@@ -4,9 +4,9 @@
 
 #include "tx_fastmetadata_app.h"
 
-
+// skolelis tbd: where it shoud be defined?
 #define ST_PKT_ST41_PAYLOAD_MAX_BYTES \
-  (1460 - sizeof(struct st41_rtp_hdr))
+  (1460 - sizeof(struct st41_rtp_hdr) - 8) // skolelis tbd: why here we have "-8" ? (value found experimentally. "-7" would be not enough!)
 
 static int app_tx_fmd_next_frame(void* priv, uint16_t* next_frame_idx,
                                  struct st41_tx_frame_meta* meta) {
@@ -79,6 +79,7 @@ static void app_tx_fmd_build_frame(struct st_app_tx_fmd_session* s,
   uint16_t data_item_length_bytes = s->st41_source_end - s->st41_frame_cursor > ST_PKT_ST41_PAYLOAD_MAX_BYTES
                           ? ST_PKT_ST41_PAYLOAD_MAX_BYTES
                           : s->st41_source_end - s->st41_frame_cursor;
+  
   dst->data_item_length_bytes = data_item_length_bytes;
   dst->data = s->st41_frame_cursor;
   s->st41_frame_cursor += data_item_length_bytes;
@@ -108,7 +109,7 @@ static void* app_tx_fmd_frame_thread(void* arg) {
 
     struct st41_frame* frame_addr = st41_tx_get_framebuffer(s->handle, producer_idx);
     app_tx_fmd_build_frame(s, frame_addr);
-
+  
     st_pthread_mutex_lock(&s->st41_wake_mutex);
     framebuff->size = sizeof(*frame_addr);
     framebuff->stat = ST_TX_FRAME_READY;
@@ -191,9 +192,11 @@ static void app_tx_fmd_build_rtp(struct st_app_tx_fmd_session* s, void* usrptr,
   /* generate one fmd rtp for test purpose */
   struct st41_rtp_hdr* hdr = (struct st41_rtp_hdr*)usrptr;
   uint8_t* payload_hdr = (uint8_t*)(&hdr[1]);
-  uint16_t data_item_length_bytes = s->st41_source_end - s->st41_frame_cursor > ST_PKT_ST41_PAYLOAD_MAX_BYTES
-                          ? ST_PKT_ST41_PAYLOAD_MAX_BYTES
+  uint16_t data_item_length_bytes = s->st41_source_end - s->st41_frame_cursor > (MTL_PKT_MAX_RTP_BYTES-16) 
+                          ? (MTL_PKT_MAX_RTP_BYTES-16)
                           : s->st41_source_end - s->st41_frame_cursor;
+  // skolelis tbd: (MTL_PKT_MAX_RTP_BYTES-16) - this is limit found in experimental way. no ST_PKT_ST41_PAYLOAD_MAX_BYTES !!!
+
   uint16_t data_item_length;
   data_item_length = (data_item_length_bytes + 3) / 4; /* expressed in number of 4-byte words */
   hdr->base.marker = 1;
@@ -209,9 +212,9 @@ static void app_tx_fmd_build_rtp(struct st_app_tx_fmd_session* s, void* usrptr,
   s->st41_seq_id++;
   s->st41_rtp_tmstamp++;
 
-  // skolelis what for we have her this htonl() ??? payload_hdr->swaped_second_hdr_chunk = htonl(payload_hdr->swaped_second_hdr_chunk);
+  // skolelis tbd: what for we have her this htonl() ??? payload_hdr->swaped_second_hdr_chunk = htonl(payload_hdr->swaped_second_hdr_chunk);
   for (int i = 0; i < data_item_length_bytes; i++) {
-    payload_hdr[i] = s->st41_frame_cursor[i]; //skolelis tu ustal dobrze wskaznik na start paylodu a moze nawet 4-bajtowy?
+    payload_hdr[i] = s->st41_frame_cursor[i]; // skolelis tbd: here have the proper pointer on payload start, and maybe even 4-byte word?
   }
   /* filling with 0's the remianing bytes of last 4-byte word */
   for (int i = data_item_length_bytes; i < data_item_length * 4; i++) {
@@ -219,7 +222,12 @@ static void app_tx_fmd_build_rtp(struct st_app_tx_fmd_session* s, void* usrptr,
   }
 
   *mbuf_len = sizeof(struct st41_rtp_hdr) + data_item_length * 4;
-  hdr->data_item_length = htons(data_item_length); //tbd skolelis htons() ???
+  hdr->st41_hdr_chunk.data_item_length = data_item_length; // skolelis tbd: htons() ???
+  hdr->st41_hdr_chunk.data_item_type = s->fmd_dit;
+  hdr->st41_hdr_chunk.data_item_k_bit = s->fmd_k_bit;
+
+  hdr->swaped_st41_hdr_chunk = htonl(hdr->swaped_st41_hdr_chunk); // skolelis tbd: and I added it instead of htons() 1 line above
+  
   s->st41_frame_cursor += data_item_length_bytes;
   if (s->st41_frame_cursor == s->st41_source_end)
     s->st41_frame_cursor = s->st41_source_begin;
@@ -320,7 +328,7 @@ static int app_tx_fmd_close_source(struct st_app_tx_fmd_session* s) {
 static int app_tx_fmd_start_source(struct st_app_tx_fmd_session* s) {
   int ret = -EINVAL;
   int idx = s->idx;
-
+  
   s->st41_app_thread_stop = false;
   if (s->st41_pcap_input)
     ret = pthread_create(&s->st41_app_thread, NULL, app_tx_fmd_pcap_thread, (void*)s);
@@ -435,6 +443,8 @@ static int app_tx_fmd_init(struct st_app_context* ctx, st_json_fastmetadata_sess
   ops.notify_rtp_done = app_tx_fmd_rtp_done;
   ops.framebuff_cnt = s->framebuff_cnt;
   ops.fps = fmd ? fmd->info.fmd_fps : ST_FPS_P59_94;
+  ops.fmd_dit = fmd->info.fmd_dit;
+  ops.fmd_k_bit = fmd->info.fmd_k_bit;
   s->st41_pcap_input = false;
   ops.type = fmd ? fmd->info.type : ST41_TYPE_FRAME_LEVEL;
   ops.interlaced = fmd ? fmd->info.interlaced : false;
@@ -464,6 +474,10 @@ static int app_tx_fmd_init(struct st_app_context* ctx, st_json_fastmetadata_sess
     return -EIO;
   }
 
+  /* added this s... = fmd... for RTP mode to function (by skolelis)*/
+  s->fmd_dit = fmd->info.fmd_dit;
+  s->fmd_k_bit = fmd->info.fmd_k_bit;
+
   s->handle = handle;
   snprintf(s->st41_source_url, sizeof(s->st41_source_url), "%s",
            fmd ? fmd->info.fmd_url : ctx->tx_fmd_url);
@@ -508,6 +522,7 @@ int st_app_tx_fmd_sessions_init(struct st_app_context* ctx) {
     s->idx = i;
     ret = app_tx_fmd_init(ctx, ctx->json_ctx ? &ctx->json_ctx->tx_fmd_sessions[i] : NULL,
                           s);
+
     if (ret < 0) {
       err("%s(%d), app_tx_fmd_session_init fail %d\n", __func__, i, ret);
       return ret;
diff --git a/include/st40_api.h b/include/st40_api.h
index 08b239e79..2660e1180 100644
--- a/include/st40_api.h
+++ b/include/st40_api.h
@@ -200,7 +200,7 @@ struct st40_meta {
 /**
  * Max number of meta in one ST2110-40(ancillary) frame
  */
-#define ST40_MAX_META (20) //skolelis tbd according to rf8331 the limit is 255 (if it is the proper field for that) !!!
+#define ST40_MAX_META (20) // skolelis tbd: according to rf8331 the limit is 255 (if it is the proper field for that) !!!
 
 /**
  * Structure for ST2110-40(ancillary) frame
diff --git a/include/st41_api.h b/include/st41_api.h
index 9bc2cd35b..54d51d48b 100644
--- a/include/st41_api.h
+++ b/include/st41_api.h
@@ -82,19 +82,44 @@ enum st41_type {
 };
 
 /**
- * A structure describing a st2110-41 (fast metadata framework) rtp header
+ * A structure describing a st2110-41(fast metadata) rtp header
  */
+#ifdef MTL_LITTLE_ENDIAN
 MTL_PACK(struct st41_rtp_hdr { // skolelis tbd: should we add little/big endian (double) versions struct to this structure (like in other places)?
   /** Rtp rfc3550 base hdr */
   struct st_rfc3550_rtp_hdr base;
-
-  /** Data Item Type */
-  uint32_t data_item_type : 22;
-  /** Data Item K-bit */
-  uint8_t data_item_k_bit : 1;  // skolelis tbd: is it not better to have here uint_32_t type for compatibility with other 22 bits?
-  /** Data Item Contents - Number of 32-bit data elements that follow */
-  uint16_t data_item_length : 9;  // skolelis tbd: is it not better to have here uint_32_t type for compatibility with other 22 bits?
+  union {
+    struct {
+      /** Data Item Contents - Number of 32-bit data elements that follow */
+      uint32_t data_item_length : 9;  // skolelis tbd: is it not better to have here uint_32_t type for compatibility with other 22 bits?
+      /** Data Item K-bit */
+      uint32_t data_item_k_bit : 1;  // skolelis tbd: is it not better to have here uint_32_t type for compatibility with other 22 bits?
+      /** Data Item Type */
+      uint32_t data_item_type : 22;
+    } st41_hdr_chunk;
+    /** Handle to make operating on st41_hdr_chunk buffer easier */
+    uint32_t swaped_st41_hdr_chunk;
+  };
 });
+#else
+MTL_PACK(struct st41_rtp_hdr { // skolelis tbd: should we add little/big endian (double) versions struct to this structure (like in other places)?
+  /** Rtp rfc3550 base hdr */
+  struct st_rfc3550_rtp_hdr base;
+  union {
+    struct {
+      /** Data Item Type */
+      uint32_t data_item_type : 22;
+      /** Data Item K-bit */
+      uint32_t data_item_k_bit : 1;  // skolelis tbd: is it not better to have here uint_32_t type for compatibility with other 22 bits?
+      /** Data Item Contents - Number of 32-bit data elements that follow */
+      uint32_t data_item_length : 9;  // skolelis tbd: is it not better to have here uint_32_t type for compatibility with other 22 bits?
+    } st41_hdr_chunk;
+    /** Handle to make operating on st41_hdr_chunk buffer easier */
+    uint32_t swaped_st41_hdr_chunk;
+  };
+});
+#endif
+
 
 /**
  * Structure for ST2110-41(fast metadata) frame
@@ -142,6 +167,11 @@ struct st41_tx_ops {
   enum st_fps fps;
   /** Mandatory. 7 bits payload type define in RFC3550 */
   uint8_t payload_type;
+  /** Mandatory. 22 bits data item type */
+  uint32_t fmd_dit;
+  /** Mandatory. 1 bit data item K-bit */
+  uint8_t fmd_k_bit;
+
   /** Mandatory. interlaced or not */
   bool interlaced;
 
@@ -233,6 +263,7 @@ struct st41_rx_ops {
   /** Optional. see ST41_RX_FLAG_* for possible flags */
   uint32_t flags;
 
+
   /** Mandatory. rtp ring queue size, must be power of 2 */
   uint32_t rtp_ring_size;
   /**
diff --git a/lib/src/st2110/st_fastmetadata.c b/lib/src/st2110/st_fastmetadata.c
index 0886c01dc..076fdc3aa 100644
--- a/lib/src/st2110/st_fastmetadata.c
+++ b/lib/src/st2110/st_fastmetadata.c
@@ -5,4 +5,4 @@
 #include "../mt_log.h"
 
 
-//skolelis tbd remove this file if empty
+// skolelis tbd: remove this file if empty
diff --git a/lib/src/st2110/st_header.h b/lib/src/st2110/st_header.h
index 439908362..5b4644f79 100644
--- a/lib/src/st2110/st_header.h
+++ b/lib/src/st2110/st_header.h
@@ -154,7 +154,7 @@ struct st_frame_trans {
     struct st30_tx_frame_meta ta_meta;
     struct st30_rx_frame_meta ra_meta; /* not use now */
     struct st40_tx_frame_meta tc_meta;
-    struct st41_tx_frame_meta tf_meta; //skolelis TBD - field for st41 transport ? (fast meta data -> "f") !!!
+    struct st41_tx_frame_meta tf_meta; // skolelis tbd: - field for st41 transport ? (fast meta data -> "f") !!!
   };
 };
 
diff --git a/lib/src/st2110/st_tx_fastmetadata_session.c b/lib/src/st2110/st_tx_fastmetadata_session.c
index 82ff09c3d..62e055f8d 100644
--- a/lib/src/st2110/st_tx_fastmetadata_session.c
+++ b/lib/src/st2110/st_tx_fastmetadata_session.c
@@ -422,10 +422,10 @@ static void tx_fastmetadata_session_build_packet(struct st_tx_fastmetadata_sessi
   uint16_t data_item_length = (data_item_length_bytes + 3) / 4; /* expressed in number of 4-byte words */
 
   if (!(data_item_length_bytes > s->max_pkt_len)) {
-    // skolelis what for we have her this htonl() ???      payload->swaped_second_hdr_chunk = htonl(payload->swaped_second_hdr_chunk);
+    // skolelis tbd: what for we have here this htonl() ???      payload->swaped_second_hdr_chunk = htonl(payload->swaped_second_hdr_chunk);
     int offset = 0;
     for (int i = 0; i < data_item_length_bytes; i++) {
-      payload[i] = src->data[offset++]; //skolelis tu ustal dobrze wskaznik na start paylodu a moze nawet 4-bajtowy?
+      payload[i] = src->data[offset++]; // skolelis tbd: here take care about proper pointer on paylod start and maybe even as  4-byte word ?
     }
     /* filling with 0's the remianing bytes of last 4-byte word */
     for (int i = data_item_length_bytes; i < data_item_length * 4; i++) {
@@ -435,8 +435,12 @@ static void tx_fastmetadata_session_build_packet(struct st_tx_fastmetadata_sessi
 
   pkt->data_len += sizeof(struct st41_rtp_hdr) + data_item_length * 4;
   pkt->pkt_len = pkt->data_len;
-  rtp->data_item_length = htons(data_item_length); //tbd skolelis what is the proper calculation?
-  // skolelis tbd: czy zoistawic te linie? rtp->base.marker = 1;
+  rtp->st41_hdr_chunk.data_item_type = s->ops.fmd_dit;
+  rtp->st41_hdr_chunk.data_item_k_bit = s->ops.fmd_k_bit;
+  rtp->st41_hdr_chunk.data_item_length = data_item_length; // skolelis tbd: I added this line without htons() (line below)
+  //rtp->st41_hdr_chunk.data_item_length = htons(data_item_length); // skolelis tbd: what is the proper calculation?
+  rtp->swaped_st41_hdr_chunk = htonl(rtp->swaped_st41_hdr_chunk); // skolelis tbd: and I added it instead of line up
+  // skolelis tbd: should this line be kept? rtp->base.marker = 1;
   dbg("%s(%d), payload_size (data_item_length_bytes) %d\n", __func__, s->idx, 
       data_item_length_bytes);
 
@@ -473,10 +477,10 @@ static void tx_fastmetadata_session_build_rtp_packet(struct st_tx_fastmetadata_s
   uint16_t data_item_length = (data_item_length_bytes + 3) / 4; /* expressed in number of 4-byte words */
 
   if (!(data_item_length_bytes > s->max_pkt_len)) {
-    // skolelis what for we have her this htonl() ???      payload->swaped_second_hdr_chunk = htonl(payload->swaped_second_hdr_chunk);
+    // skolelis tbd: what for we have here this htonl() ???      payload->swaped_second_hdr_chunk = htonl(payload->swaped_second_hdr_chunk);
     int offset = 0;
     for (int i = 0; i < data_item_length_bytes; i++) {
-      payload[i] = src->data[offset++]; //skolelis tu ustal dobrze wskaznik na start paylodu a moze nawet 4-bajtowy?
+      payload[i] = src->data[offset++]; // skolelis tbd: here take care about proper pointer on paylod start and maybe even as 4-byte word ?
     }
     /* filling with 0's the remianing bytes of last 4-byte word */
     for (int i = data_item_length_bytes; i < data_item_length * 4; i++) {
@@ -486,8 +490,14 @@ static void tx_fastmetadata_session_build_rtp_packet(struct st_tx_fastmetadata_s
 
   pkt->data_len = sizeof(struct st41_rtp_hdr) + data_item_length * 4;
   pkt->pkt_len = pkt->data_len;
-  rtp->data_item_length = htons(data_item_length); //tbd skolelis what is the proper calculation?
-   /// skolelis tbd czy to zostawic    rtp->base.marker = 1;
+
+  rtp->st41_hdr_chunk.data_item_type = s->ops.fmd_dit;
+  rtp->st41_hdr_chunk.data_item_k_bit = s->ops.fmd_k_bit;
+  rtp->st41_hdr_chunk.data_item_length = data_item_length; // htons(data_item_length); // skolelis tbd: what is the proper calculation?
+  rtp->swaped_st41_hdr_chunk = htonl(rtp->swaped_st41_hdr_chunk);
+
+
+   /// skolelis tbd: should this line be kept?   rtp->base.marker = 1;
   dbg("%s(%d), payload_size (data_item_length_bytes) %d\n", __func__, s->idx, 
       data_item_length_bytes);
 
@@ -518,7 +528,7 @@ static int tx_fastmetadata_session_rtp_update_packet(struct mtl_main_impl* impl,
     s->st41_pkt_idx = 0;
     rte_atomic32_inc(&s->st41_stat_frame_cnt);
     s->st41_rtp_time = rtp->tmstamp;
-    bool second_field = false; //skolelis tbd decide if it should be true or false (interlaced?)
+    bool second_field = false; // skolelis tbd: decide if it should be true or false (interlaced?)
     
     tx_fastmetadata_session_sync_pacing(impl, s, false, 0, second_field);
   }
@@ -571,7 +581,7 @@ static int tx_fastmetadata_session_build_packet_chain(struct mtl_main_impl* impl
         s->st41_pkt_idx = 0;
         rte_atomic32_inc(&s->st41_stat_frame_cnt);
         s->st41_rtp_time = rtp->base.tmstamp;
-        bool second_field = false;  // skolelis tbd decide if true or false (interlaced)?
+        bool second_field = false;  // skolelis tbd: decide if true or false (interlaced)?
         tx_fastmetadata_session_sync_pacing(impl, s, false, 0, second_field);
       }
       if (s->ops.flags & ST41_TX_FLAG_USER_TIMESTAMP) {
@@ -669,7 +679,7 @@ static int tx_fastmetadata_session_tasklet_frame(struct mtl_main_impl* impl,
       return MTL_TASKLET_ALL_DONE;
     }
   }
-
+  
   if (ST41_TX_STAT_WAIT_FRAME == s->st41_frame_stat) {
     uint16_t next_frame_idx;
     int data_item_length_bytes = 0;
@@ -732,7 +742,7 @@ static int tx_fastmetadata_session_tasklet_frame(struct mtl_main_impl* impl,
     MT_USDT_ST41_TX_FRAME_NEXT(s->mgr->idx, s->idx, next_frame_idx, frame->addr,
                                0, data_item_length_bytes);
   }
-
+  
   /* sync pacing */
   if (s->calculate_time_cursor) {
     struct st_frame_trans* frame = &s->st41_frames[s->st41_frame_idx];
@@ -789,6 +799,7 @@ static int tx_fastmetadata_session_tasklet_frame(struct mtl_main_impl* impl,
       s->stat_build_ret_code = -STI_FRAME_PKT_ALLOC_FAIL;
       return MTL_TASKLET_ALL_DONE;
     }
+
     tx_fastmetadata_session_build_rtp_packet(s, pkt_rtp);
     tx_fastmetadata_session_build_packet_chain(impl, s, pkt, pkt_rtp, MTL_SESSION_PORT_P);
 
@@ -1662,7 +1673,7 @@ static int tx_fastmetadata_sessions_mgr_init(struct mtl_main_impl* impl,
   struct mtl_tasklet_ops ops;
   int i;
 
-  RTE_BUILD_BUG_ON(sizeof(struct st41_fmd_hdr) != 58); //skolelis tbd used to be 62 for ANC, and IMHO should be 58!!!
+  RTE_BUILD_BUG_ON(sizeof(struct st41_fmd_hdr) != 58); // skolelis tbd: used to be 62 for ANC, and IMHO should be 58!!!
 
   mgr->parent = impl;
   mgr->idx = idx;