diff --git a/trunk/src/kernel/srs_kernel_codec.cpp b/trunk/src/kernel/srs_kernel_codec.cpp
index 267435ca9..7351573c0 100644
--- a/trunk/src/kernel/srs_kernel_codec.cpp
+++ b/trunk/src/kernel/srs_kernel_codec.cpp
@@ -553,10 +553,8 @@ srs_error_t SrsFormat::on_audio(int64_t timestamp, char* data, int size)
     SrsBuffer* buffer = new SrsBuffer(data, size);
     SrsAutoFree(SrsBuffer, buffer);
     
-    // audio decode
-    if (!buffer->require(1)) {
-        return srs_error_new(ERROR_HLS_DECODE_ERROR, "aac decode sound_format");
-    }
+    // We already checked the size is positive and data is not NULL.
+    srs_assert(buffer->require(1));
     
     // @see: E.4.2 Audio Tags, video_file_format_spec_v10_1.pdf, page 76
     uint8_t v = buffer->read_1bytes();
@@ -599,10 +597,8 @@ srs_error_t SrsFormat::on_video(int64_t timestamp, char* data, int size)
     SrsBuffer* buffer = new SrsBuffer(data, size);
     SrsAutoFree(SrsBuffer, buffer);
     
-    // video decode
-    if (!buffer->require(1)) {
-        return srs_error_new(ERROR_HLS_DECODE_ERROR, "decode frame_type");
-    }
+    // We already checked the size is positive and data is not NULL.
+    srs_assert(buffer->require(1));
     
     // @see: E.4.3 Video Tags, video_file_format_spec_v10_1.pdf, page 78
     int8_t frame_type = buffer->read_1bytes();
diff --git a/trunk/src/utest/srs_utest_kernel.cpp b/trunk/src/utest/srs_utest_kernel.cpp
index 87a1a721e..1898c533a 100644
--- a/trunk/src/utest/srs_utest_kernel.cpp
+++ b/trunk/src/utest/srs_utest_kernel.cpp
@@ -2690,6 +2690,39 @@ VOID TEST(KernelCodecTest, AVFrame)
     }
 }
 
+VOID TEST(KernelCodecTest, IsSequenceHeaderSpecial)
+{
+	if (true) {
+		SrsFormat f;
+		EXPECT_FALSE(f.is_avc_sequence_header());
+
+		f.vcodec = new SrsVideoCodecConfig();
+		f.video = new SrsVideoFrame();
+		EXPECT_FALSE(f.is_avc_sequence_header());
+
+		f.vcodec->id = SrsVideoCodecIdAVC;
+		EXPECT_FALSE(f.is_avc_sequence_header());
+
+		f.video->avc_packet_type = SrsVideoAvcFrameTraitSequenceHeader;
+		EXPECT_TRUE(f.is_avc_sequence_header());
+	}
+
+	if (true) {
+		SrsFormat f;
+		EXPECT_FALSE(f.is_avc_sequence_header());
+
+		f.vcodec = new SrsVideoCodecConfig();
+		f.video = new SrsVideoFrame();
+		EXPECT_FALSE(f.is_avc_sequence_header());
+
+		f.vcodec->id = SrsVideoCodecIdHEVC;
+		EXPECT_FALSE(f.is_avc_sequence_header());
+
+		f.video->avc_packet_type = SrsVideoAvcFrameTraitSequenceHeader;
+		EXPECT_TRUE(f.is_avc_sequence_header());
+	}
+}
+
 VOID TEST(KernelCodecTest, AudioFormat)
 {
     if (true) {
@@ -2805,6 +2838,137 @@ VOID TEST(KernelCodecTest, AudioFormat)
     }
 }
 
+VOID TEST(KernelCodecTest, VideoFormatSepcial)
+{
+	srs_error_t err;
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)"\x17", 1));
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)"\x27", 1));
+    }
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        uint8_t buf[] = {
+            0x17, // 1, Keyframe; 7, AVC.
+            0x00, // 0, Sequence header.
+            0x00, 0x00, 0x00, // Timestamp.
+        };
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)buf, sizeof(buf)));
+    }
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        uint8_t buf[] = {
+            0x17, // 1, Keyframe; 7, AVC.
+            0x00, // 0, Sequence header.
+            0x00, 0x00, 0x00, // Timestamp.
+            // AVC extra data, SPS/PPS.
+            0x00, 0x00, 0x00, 0x00,
+            0x02, // lengthSizeMinusOne
+            0x00,
+        };
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)buf, sizeof(buf)));
+    }
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        uint8_t buf[] = {
+            0x17, // 1, Keyframe; 7, AVC.
+            0x00, // 0, Sequence header.
+            0x00, 0x00, 0x00, // Timestamp.
+            // AVC extra data, SPS/PPS.
+            0x00, 0x00, 0x00, 0x00,
+            0x00, // lengthSizeMinusOne
+            0x00, // SPS
+        };
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)buf, sizeof(buf)));
+    }
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        uint8_t buf[] = {
+            0x17, // 1, Keyframe; 7, AVC.
+            0x00, // 0, Sequence header.
+            0x00, 0x00, 0x00, // Timestamp.
+            // AVC extra data, SPS/PPS.
+            0x00, 0x00, 0x00, 0x00,
+            0x00, // lengthSizeMinusOne
+            0x01, // SPS
+        };
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)buf, sizeof(buf)));
+    }
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        uint8_t buf[] = {
+            0x17, // 1, Keyframe; 7, AVC.
+            0x00, // 0, Sequence header.
+            0x00, 0x00, 0x00, // Timestamp.
+            // AVC extra data, SPS/PPS.
+            0x00, 0x00, 0x00, 0x00,
+            0x00, // lengthSizeMinusOne
+            0x01, 0x00, 0x00, // SPS, empty
+        };
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)buf, sizeof(buf)));
+    }
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        uint8_t buf[] = {
+            0x17, // 1, Keyframe; 7, AVC.
+            0x00, // 0, Sequence header.
+            0x00, 0x00, 0x00, // Timestamp.
+            // AVC extra data, SPS/PPS.
+            0x00, 0x00, 0x00, 0x00,
+            0x00, // lengthSizeMinusOne
+            0x01, 0x00, 0x00, // SPS, empty
+            0x00, // PPS
+        };
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)buf, sizeof(buf)));
+    }
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        uint8_t buf[] = {
+            0x17, // 1, Keyframe; 7, AVC.
+            0x00, // 0, Sequence header.
+            0x00, 0x00, 0x00, // Timestamp.
+            // AVC extra data, SPS/PPS.
+            0x00, 0x00, 0x00, 0x00,
+            0x00, // lengthSizeMinusOne
+            0x01, 0x00, 0x00, // SPS
+            0x01, // PPS
+        };
+        HELPER_EXPECT_FAILED(f.on_video(0, (char*)buf, sizeof(buf)));
+    }
+
+    if (true) {
+        SrsFormat f;
+        EXPECT_TRUE(srs_success == f.initialize());
+        uint8_t buf[] = {
+            0x17, // 1, Keyframe; 7, AVC.
+            0x00, // 0, Sequence header.
+            0x00, 0x00, 0x00, // Timestamp.
+            // AVC extra data, SPS/PPS.
+            0x00, 0x00, 0x00, 0x00,
+            0x00, // lengthSizeMinusOne
+            0x01, 0x00, 0x00, // SPS, empty
+            0x01, 0x00, 0x00, // PPS, empty
+        };
+        HELPER_EXPECT_SUCCESS(f.on_video(0, (char*)buf, sizeof(buf)));
+    }
+}
+
 VOID TEST(KernelCodecTest, VideoFormat)
 {
     if (true) {