Add: support for saving video to file in st20p (#1017)

Implement video saving functionality in st20p RxTxApp.
Utilize the existing JSON parsing for the "st20p_url" field.
To use, add "st20p_url" to the JSON "st20p" section
configuration.

app/src/app_base.h

@@ -551,6 +551,8 @@ struct st_app_rx_st20p_session {
   pthread_t st20p_app_thread;
   bool st20p_app_thread_stop;
 
+  char st20p_destination_url[ST_APP_URL_MAX_LEN];
+  FILE* st20p_destination_file;
   struct st_display* display;
   uint32_t pcapng_max_pkts;
 
@@ -717,6 +719,7 @@ struct st_app_context {
   struct st_app_rx_st22p_session* rx_st22p_sessions;
   int rx_st22p_session_cnt;
 
+  char rx_st20p_url[ST_APP_URL_MAX_LEN]; /* save st20p content url*/
   struct st_app_rx_st20p_session* rx_st20p_sessions;
   int rx_st20p_session_cnt;
 

app/src/parse_json.c

@@ -2089,6 +2089,10 @@ static int st_json_parse_rx_st20p(int idx, json_object* st20p_obj,
   ret = parse_st20p_transport_format(st20p_obj, st20p);
   if (ret < 0) return ret;
 
+  /* parse st20p url */
+  ret = parse_url(st20p_obj, "st20p_url", st20p->info.st20p_url);
+  if (ret < 0) return ret;
+
   /* parse display option */
   st20p->display =
       json_object_get_boolean(st_json_object_object_get(st20p_obj, "display"));

app/src/rx_st20p_app.c

@@ -9,6 +9,13 @@ static void app_rx_st20p_consume_frame(struct st_app_rx_st20p_session* s,
   struct st_display* d = s->display;
   int idx = s->idx;
 
+  if (s->st20p_destination_file) {
+    if (!fwrite(frame->addr[0], 1, s->st20p_frame_size, s->st20p_destination_file)) {
+      err("%s(%d), failed to write frame to file %s\n", __func__, idx,
+          s->st20p_destination_url);
+    }
+  }
+
   if (s->num_port > 1) {
     dbg("%s(%d): pkts_total %u, pkts per port P %u R %u\n", __func__, idx,
         frame->pkts_total, frame->pkts_recv[MTL_SESSION_PORT_P],
@@ -209,6 +216,18 @@ static int app_rx_st20p_init(struct st_app_context* ctx,
         st20p ? st20p->base.udp_port : (10000 + s->idx);
   }
 
+  if (st20p && st20p->info.st20p_url[0] != '\0') {
+    memcpy(s->st20p_destination_url, st20p->info.st20p_url, ST_APP_URL_MAX_LEN);
+    s->st20p_destination_file = fopen(s->st20p_destination_url, "wb");
+
+    if (!s->st20p_destination_file) {
+      err("%s(%d), failed to open destination file %s\n", __func__, idx,
+          s->st20p_destination_url);
+      app_rx_st20p_uinit(s);
+      return -EIO;
+    }
+  }
+
   ops.width = st20p ? st20p->info.width : 1920;
   ops.height = st20p ? st20p->info.height : 1080;
   ops.fps = st20p ? st20p->info.fps : ST_FPS_P59_94;