diff --git a/call/rtp_payload_params.cc b/call/rtp_payload_params.cc
index 18e6d9136b..f0347bc74e 100644
--- a/call/rtp_payload_params.cc
+++ b/call/rtp_payload_params.cc
@@ -604,23 +604,42 @@ void RtpPayloadParams::Vp9ToGeneric(const CodecSpecificInfoVP9& vp9_info,
     // Create the array only if it is ever used.
     last_vp9_frame_id_.resize(kPictureDiffLimit);
   }
-  if (vp9_header.inter_layer_predicted && spatial_index > 0) {
-    result.dependencies.push_back(
-        last_vp9_frame_id_[vp9_header.picture_id % kPictureDiffLimit]
-                          [spatial_index - 1]);
-  }
-  if (vp9_header.inter_pic_predicted) {
-    for (size_t i = 0; i < vp9_header.num_ref_pics; ++i) {
-      // picture_id is 15 bit number that wraps around. Though undeflow may
-      // produce picture that exceeds 2^15, it is ok because in this
-      // code block only last 7 bits of the picture_id are used.
-      uint16_t depend_on = vp9_header.picture_id - vp9_header.pid_diff[i];
+
+  if (vp9_header.flexible_mode) {
+    if (vp9_header.inter_layer_predicted && spatial_index > 0) {
       result.dependencies.push_back(
-          last_vp9_frame_id_[depend_on % kPictureDiffLimit][spatial_index]);
+          last_vp9_frame_id_[vp9_header.picture_id % kPictureDiffLimit]
+                            [spatial_index - 1]);
     }
+    if (vp9_header.inter_pic_predicted) {
+      for (size_t i = 0; i < vp9_header.num_ref_pics; ++i) {
+        // picture_id is 15 bit number that wraps around. Though undeflow may
+        // produce picture that exceeds 2^15, it is ok because in this
+        // code block only last 7 bits of the picture_id are used.
+        uint16_t depend_on = vp9_header.picture_id - vp9_header.pid_diff[i];
+        result.dependencies.push_back(
+            last_vp9_frame_id_[depend_on % kPictureDiffLimit][spatial_index]);
+      }
+    }
+    last_vp9_frame_id_[vp9_header.picture_id % kPictureDiffLimit]
+                      [spatial_index] = shared_frame_id;
+  } else {
+    // Implementing general conversion logic for non-flexible mode requires some
+    // work and we will almost certainly never need it, so for now support only
+    // non-layerd streams.
+    if (spatial_index > 0 || temporal_index > 0) {
+      // Prefer to generate no generic layering than an inconsistent one.
+      rtp_video_header.generic.reset();
+      return;
+    }
+
+    if (vp9_header.inter_pic_predicted) {
+      // Since we only support non-scalable streams we only need to save the
+      // last frame id.
+      result.dependencies.push_back(last_vp9_frame_id_[0][0]);
+    }
+    last_vp9_frame_id_[0][0] = shared_frame_id;
   }
-  last_vp9_frame_id_[vp9_header.picture_id % kPictureDiffLimit][spatial_index] =
-      shared_frame_id;
 
   result.active_decode_targets =
       ((uint32_t{1} << num_temporal_layers * num_active_spatial_layers) - 1);
diff --git a/call/rtp_payload_params_unittest.cc b/call/rtp_payload_params_unittest.cc
index cfd01018fe..8481b5f93f 100644
--- a/call/rtp_payload_params_unittest.cc
+++ b/call/rtp_payload_params_unittest.cc
@@ -567,6 +567,7 @@ TEST(RtpPayloadParamsVp9ToGenericTest, NoScalability) {
   EncodedImage encoded_image;
   CodecSpecificInfo codec_info;
   codec_info.codecType = kVideoCodecVP9;
+  codec_info.codecSpecific.VP9.flexible_mode = true;
   codec_info.codecSpecific.VP9.num_spatial_layers = 1;
   codec_info.codecSpecific.VP9.temporal_idx = kNoTemporalIdx;
   codec_info.codecSpecific.VP9.first_frame_in_picture = true;
@@ -611,6 +612,55 @@ TEST(RtpPayloadParamsVp9ToGenericTest, NoScalability) {
   EXPECT_EQ(header.generic->chain_diffs[0], 3 - 1);
 }
 
+TEST(RtpPayloadParamsVp9ToGenericTest, NoScalabilityNonFlexibleMode) {
+  RtpPayloadState state;
+  RtpPayloadParams params(/*ssrc=*/123, &state, FieldTrialBasedConfig());
+
+  EncodedImage encoded_image;
+  CodecSpecificInfo codec_info;
+  codec_info.codecType = kVideoCodecVP9;
+  codec_info.codecSpecific.VP9.flexible_mode = false;
+  codec_info.codecSpecific.VP9.num_spatial_layers = 1;
+  codec_info.codecSpecific.VP9.temporal_idx = kNoTemporalIdx;
+  codec_info.codecSpecific.VP9.first_frame_in_picture = true;
+  codec_info.end_of_picture = true;
+
+  // Key frame.
+  encoded_image._frameType = VideoFrameType::kVideoFrameKey;
+  codec_info.codecSpecific.VP9.inter_pic_predicted = false;
+  RTPVideoHeader key_header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info,
+                               /*shared_frame_id=*/1);
+
+  ASSERT_TRUE(key_header.generic);
+  EXPECT_EQ(key_header.generic->spatial_index, 0);
+  EXPECT_EQ(key_header.generic->temporal_index, 0);
+  EXPECT_EQ(key_header.generic->frame_id, 1);
+  ASSERT_THAT(key_header.generic->decode_target_indications, Not(IsEmpty()));
+  EXPECT_EQ(key_header.generic->decode_target_indications[0],
+            DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(key_header.generic->dependencies, IsEmpty());
+  ASSERT_THAT(key_header.generic->chain_diffs, Not(IsEmpty()));
+  EXPECT_EQ(key_header.generic->chain_diffs[0], 0);
+
+  encoded_image._frameType = VideoFrameType::kVideoFrameDelta;
+  codec_info.codecSpecific.VP9.inter_pic_predicted = true;
+  RTPVideoHeader delta_header =
+      params.GetRtpVideoHeader(encoded_image, &codec_info,
+                               /*shared_frame_id=*/3);
+
+  ASSERT_TRUE(delta_header.generic);
+  EXPECT_EQ(delta_header.generic->spatial_index, 0);
+  EXPECT_EQ(delta_header.generic->temporal_index, 0);
+  EXPECT_EQ(delta_header.generic->frame_id, 3);
+  ASSERT_THAT(delta_header.generic->decode_target_indications, Not(IsEmpty()));
+  EXPECT_EQ(delta_header.generic->decode_target_indications[0],
+            DecodeTargetIndication::kSwitch);
+  EXPECT_THAT(delta_header.generic->dependencies, ElementsAre(1));
+  ASSERT_THAT(delta_header.generic->chain_diffs, Not(IsEmpty()));
+  EXPECT_EQ(delta_header.generic->chain_diffs[0], 3 - 1);
+}
+
 TEST(RtpPayloadParamsVp9ToGenericTest, TemporalScalabilityWith2Layers) {
   // Test with 2 temporal layers structure that is not used by webrtc:
   //    1---3   5
@@ -622,6 +672,7 @@ TEST(RtpPayloadParamsVp9ToGenericTest, TemporalScalabilityWith2Layers) {
   EncodedImage image;
   CodecSpecificInfo info;
   info.codecType = kVideoCodecVP9;
+  info.codecSpecific.VP9.flexible_mode = true;
   info.codecSpecific.VP9.num_spatial_layers = 1;
   info.codecSpecific.VP9.first_frame_in_picture = true;
   info.end_of_picture = true;
@@ -732,6 +783,7 @@ TEST(RtpPayloadParamsVp9ToGenericTest, TemporalScalabilityWith3Layers) {
   EncodedImage image;
   CodecSpecificInfo info;
   info.codecType = kVideoCodecVP9;
+  info.codecSpecific.VP9.flexible_mode = true;
   info.codecSpecific.VP9.num_spatial_layers = 1;
   info.codecSpecific.VP9.first_frame_in_picture = true;
   info.end_of_picture = true;
@@ -885,6 +937,7 @@ TEST(RtpPayloadParamsVp9ToGenericTest, SpatialScalabilityKSvc) {
   EncodedImage image;
   CodecSpecificInfo info;
   info.codecType = kVideoCodecVP9;
+  info.codecSpecific.VP9.flexible_mode = true;
   info.codecSpecific.VP9.num_spatial_layers = 2;
   info.codecSpecific.VP9.first_frame_in_picture = true;
 
@@ -993,6 +1046,7 @@ TEST(RtpPayloadParamsVp9ToGenericTest,
   EncodedImage image;
   CodecSpecificInfo info;
   info.codecType = kVideoCodecVP9;
+  info.codecSpecific.VP9.flexible_mode = true;
   info.codecSpecific.VP9.num_spatial_layers = 1;
   info.codecSpecific.VP9.first_frame_in_picture = true;