diff --git a/webrtc/modules/audio_coding/neteq/timestamp_scaler.cc b/webrtc/modules/audio_coding/neteq/timestamp_scaler.cc
index b228e01..1f28639 100644
--- a/webrtc/modules/audio_coding/neteq/timestamp_scaler.cc
+++ b/webrtc/modules/audio_coding/neteq/timestamp_scaler.cc
@@ -11,7 +11,6 @@
 #include "webrtc/modules/audio_coding/neteq/timestamp_scaler.h"
 
 #include "webrtc/modules/audio_coding/neteq/decoder_database.h"
-#include "webrtc/modules/audio_coding/neteq/defines.h"
 #include "webrtc/system_wrappers/include/logging.h"
 
 namespace webrtc {
@@ -43,39 +42,25 @@
     // Payload type is unknown. Do not scale.
     return external_timestamp;
   }
-  switch (info->codec_type) {
-    case NetEqDecoder::kDecoderG722:
-    case NetEqDecoder::kDecoderG722_2ch: {
-      // Use timestamp scaling with factor 2 (two output samples per RTP
-      // timestamp).
-      numerator_ = 2;
-      denominator_ = 1;
-      break;
-    }
-    case NetEqDecoder::kDecoderAVT:
-    case NetEqDecoder::kDecoderCNGnb:
-    case NetEqDecoder::kDecoderCNGwb:
-    case NetEqDecoder::kDecoderCNGswb32kHz:
-    case NetEqDecoder::kDecoderCNGswb48kHz: {
-      // Do not change the timestamp scaling settings for DTMF or CNG.
-      break;
-    }
-    default: {
-      // Do not use timestamp scaling for any other codec.
-      numerator_ = 1;
-      denominator_ = 1;
-      break;
+  if (!(info->IsComfortNoise() || info->IsDtmf())) {
+    // Do not change the timestamp scaling settings for DTMF or CNG.
+    numerator_ = info->SampleRateHz();
+    if (info->codec_type == NetEqDecoder::kDecoderArbitrary) {
+      // We have no format mapping for "arbitrary" external codecs, so we cannot
+      // support timestamp scaling of them.
+      denominator_ = numerator_;
+    } else {
+      denominator_ = info->GetFormat().clockrate_hz;
     }
   }
-
-  if (!(numerator_ == 1 && denominator_ == 1)) {
+  if (numerator_ != denominator_) {
     // We have a scale factor != 1.
     if (!first_packet_received_) {
       external_ref_ = external_timestamp;
       internal_ref_ = external_timestamp;
       first_packet_received_ = true;
     }
-    int64_t external_diff = external_timestamp - external_ref_;
+    const int64_t external_diff = int64_t{external_timestamp} - external_ref_;
     assert(denominator_ > 0);  // Should not be possible.
     external_ref_ = external_timestamp;
     internal_ref_ += (external_diff * numerator_) / denominator_;
@@ -88,11 +73,11 @@
 
 
 uint32_t TimestampScaler::ToExternal(uint32_t internal_timestamp) const {
-  if (!first_packet_received_ || (numerator_ == 1 && denominator_ == 1)) {
+  if (!first_packet_received_ || (numerator_ == denominator_)) {
     // Not initialized, or scale factor is 1.
     return internal_timestamp;
   } else {
-    int64_t internal_diff = internal_timestamp - internal_ref_;
+    const int64_t internal_diff = int64_t{internal_timestamp} - internal_ref_;
     assert(numerator_ > 0);  // Should not be possible.
     // Do not update references in this method.
     // Switch |denominator_| and |numerator_| to convert the other way.