diff --git a/src/internal_modules/roc_fec/reader.cpp b/src/internal_modules/roc_fec/reader.cpp
index ef17ac505..ebc04d244 100644
--- a/src/internal_modules/roc_fec/reader.cpp
+++ b/src/internal_modules/roc_fec/reader.cpp
@@ -803,18 +803,19 @@ void Reader::drop_repair_packets_from_prev_blocks_() {
 }
 
 void Reader::update_block_duration_(const packet::PacketPtr& ptr) {
-    if (!ptr->rtp()) {
-        return;
-    }
     packet::stream_timestamp_diff_t block_dur = 0;
     if (prev_block_timestamp_valid_) {
-        block_dur = packet::stream_timestamp_diff(ptr->rtp()->stream_timestamp,
-                                                  prev_block_timestamp_);
+        block_dur =
+            packet::stream_timestamp_diff(ptr->stream_timestamp(), prev_block_timestamp_);
+    }
+    if (block_dur < 0) {
+        roc_log(LogTrace, "fec reader: negative block duration");
+        prev_block_timestamp_valid_ = false;
+    } else {
+        block_max_duration_ = std::max(block_max_duration_, block_dur);
+        prev_block_timestamp_ = ptr->stream_timestamp();
+        prev_block_timestamp_valid_ = true;
     }
-    roc_panic_if_msg(block_dur < 0, "fec reader: negative block duration");
-    block_max_duration_ = std::max(block_max_duration_, block_dur);
-    prev_block_timestamp_ = ptr->rtp()->stream_timestamp;
-    prev_block_timestamp_valid_ = true;
 }
 
 packet::stream_timestamp_t Reader::max_block_duration() const {
diff --git a/src/internal_modules/roc_fec/writer.cpp b/src/internal_modules/roc_fec/writer.cpp
index b6f4cb1b2..93ec94691 100644
--- a/src/internal_modules/roc_fec/writer.cpp
+++ b/src/internal_modules/roc_fec/writer.cpp
@@ -112,7 +112,6 @@ status::StatusCode Writer::write(const packet::PacketPtr& pp) {
     }
 
     if (cur_packet_ == 0) {
-        update_block_duration_(pp);
         if (!begin_block_(pp)) {
             // TODO(gh-183): return status
             return status::StatusOK;
@@ -139,6 +138,8 @@ status::StatusCode Writer::write(const packet::PacketPtr& pp) {
 }
 
 bool Writer::begin_block_(const packet::PacketPtr& pp) {
+    update_block_duration_(pp);
+
     if (!apply_sizes_(next_sblen_, next_rblen_, pp->fec()->payload.size())) {
         return false;
     }
@@ -347,19 +348,16 @@ bool Writer::validate_source_packet_(const packet::PacketPtr& pp) {
 }
 
 void Writer::update_block_duration_(const packet::PacketPtr& ptr) {
-    if (!ptr->rtp()) {
-        return;
-    }
     packet::stream_timestamp_diff_t block_dur = 0;
     if (prev_block_timestamp_valid_) {
-        block_dur = packet::stream_timestamp_diff(ptr->rtp()->stream_timestamp,
-                                                  prev_block_timestamp_);
+        block_dur =
+            packet::stream_timestamp_diff(ptr->stream_timestamp(), prev_block_timestamp_);
     }
     if (block_dur < 0) {
         prev_block_timestamp_valid_ = false;
     } else {
         block_max_duration_ = std::max(block_max_duration_, block_dur);
-        prev_block_timestamp_ = ptr->rtp()->stream_timestamp;
+        prev_block_timestamp_ = ptr->stream_timestamp();
         prev_block_timestamp_valid_ = true;
     }
 }
diff --git a/src/tests/roc_fec/test_writer_reader.cpp b/src/tests/roc_fec/test_writer_reader.cpp
index 59ab88f2c..ead50308a 100644
--- a/src/tests/roc_fec/test_writer_reader.cpp
+++ b/src/tests/roc_fec/test_writer_reader.cpp
@@ -270,7 +270,8 @@ TEST(writer_reader, no_losses) {
                 } else {
                     CHECK(reader.is_started());
                     if (i_block > 1) {
-//                        CHECK(reader.max_block_duration() == NumSourcePackets * 10);
+                        //                        CHECK(reader.max_block_duration() ==
+                        //                        NumSourcePackets * 10);
                     }
                 }
                 CHECK(p);