diff --git a/src/audio/audio_task.cpp b/src/audio/audio_task.cpp
index 4fad3114..7e0fb207 100644
--- a/src/audio/audio_task.cpp
+++ b/src/audio/audio_task.cpp
@@ -53,20 +53,23 @@ static const char* kTag = "audio_dec";
 
 static constexpr std::size_t kSampleBufferSize = 16 * 1024;
 
-Timer::Timer(StreamInfo::Pcm format)
-    : format_(format),
-      current_seconds_(0),
-      current_sample_in_second_(0),
-      total_duration_seconds_(0) {}
-
-auto Timer::SetLengthSeconds(uint32_t len) -> void {
-  total_duration_seconds_ = len;
-  has_duration_ = true;
-}
-
-auto Timer::SetLengthBytes(uint32_t len) -> void {
-  total_duration_seconds_ = bytes_to_samples(len) / format_.sample_rate;
-  has_duration_ = true;
+Timer::Timer(const StreamInfo::Pcm& format, const Duration& duration)
+    : format_(format), current_seconds_(0), current_sample_in_second_(0) {
+  switch (duration.src) {
+    case Duration::Source::kLibTags:
+      ESP_LOGI(kTag, "using duration from libtags");
+      total_duration_seconds_ = duration.duration;
+      break;
+    case Duration::Source::kCodec:
+      ESP_LOGI(kTag, "using duration from decoder");
+      total_duration_seconds_ = duration.duration;
+      break;
+    case Duration::Source::kFileSize:
+      ESP_LOGW(kTag, "calculating duration from filesize");
+      total_duration_seconds_ =
+          bytes_to_samples(duration.duration) / format_.sample_rate;
+      break;
+  }
 }
 
 auto Timer::AddBytes(std::size_t bytes) -> void {
@@ -137,14 +140,6 @@ void AudioTask::Main() {
             if (ForwardPcmStream(*pcm, stream.data())) {
               stream.consume(stream.data().size_bytes());
             }
-            if (!timer_->has_duration()) {
-              if (stream.info().total_length_seconds()) {
-                timer_->SetLengthSeconds(*stream.info().total_length_seconds());
-              } else {
-                timer_->SetLengthBytes(
-                    stream.info().total_length_bytes().value_or(0));
-              }
-            }
             return;
           }
 
@@ -235,16 +230,20 @@ auto AudioTask::BeginDecoding(InputStream& stream) -> bool {
       .sample_rate = format.sample_rate_hz,
   };
 
-  if (!ConfigureSink(new_format)) {
-    return false;
-  }
-
+  Duration duration;
   if (format.duration_seconds) {
-    timer_->SetLengthSeconds(*format.duration_seconds);
+    duration.src = Duration::Source::kCodec;
+    duration.duration = *format.duration_seconds;
   } else if (stream.info().total_length_seconds()) {
-    timer_->SetLengthSeconds(*stream.info().total_length_seconds());
+    duration.src = Duration::Source::kLibTags;
+    duration.duration = *stream.info().total_length_seconds();
   } else {
-    timer_->SetLengthBytes(stream.info().total_length_bytes().value_or(0));
+    duration.src = Duration::Source::kFileSize;
+    duration.duration = *stream.info().total_length_bytes();
+  }
+
+  if (!ConfigureSink(new_format, duration)) {
+    return false;
   }
 
   return true;
@@ -307,7 +306,11 @@ auto AudioTask::ForwardPcmStream(StreamInfo::Pcm& format,
                                  cpp::span<const std::byte> samples) -> bool {
   // First we need to reconfigure the sink for this sample format.
   if (format != current_output_format_) {
-    if (!ConfigureSink(format)) {
+    Duration d{
+        .src = Duration::Source::kFileSize,
+        .duration = samples.size_bytes(),
+    };
+    if (!ConfigureSink(format, d)) {
       return false;
     }
   }
@@ -319,7 +322,8 @@ auto AudioTask::ForwardPcmStream(StreamInfo::Pcm& format,
   return true;
 }
 
-auto AudioTask::ConfigureSink(const StreamInfo::Pcm& format) -> bool {
+auto AudioTask::ConfigureSink(const StreamInfo::Pcm& format,
+                              const Duration& duration) -> bool {
   if (format != current_output_format_) {
     // The new format is different to the old one. Wait for the sink to drain
     // before continuing.
@@ -337,7 +341,7 @@ auto AudioTask::ConfigureSink(const StreamInfo::Pcm& format) -> bool {
   }
 
   current_output_format_ = format;
-  timer_.reset(new Timer(format));
+  timer_.reset(new Timer(format, duration));
   return true;
 }
 
diff --git a/src/audio/include/audio_task.hpp b/src/audio/include/audio_task.hpp
index 72732021..f6e9789b 100644
--- a/src/audio/include/audio_task.hpp
+++ b/src/audio/include/audio_task.hpp
@@ -18,15 +18,21 @@
 
 namespace audio {
 
+struct Duration {
+  enum class Source {
+    kLibTags,
+    kCodec,
+    kFileSize,
+  };
+  Source src;
+  uint32_t duration;
+};
+
 class Timer {
  public:
-  explicit Timer(StreamInfo::Pcm);
-
-  auto SetLengthSeconds(uint32_t) -> void;
-  auto SetLengthBytes(uint32_t) -> void;
+  Timer(const StreamInfo::Pcm&, const Duration&);
 
   auto AddBytes(std::size_t) -> void;
-  auto has_duration() const -> bool { return has_duration_; }
 
  private:
   auto bytes_to_samples(uint32_t) -> uint32_t;
@@ -36,7 +42,6 @@ class Timer {
   uint32_t current_seconds_;
   uint32_t current_sample_in_second_;
 
-  bool has_duration_;
   uint32_t total_duration_seconds_;
 };
 
@@ -57,7 +62,7 @@ class AudioTask {
 
   auto ForwardPcmStream(StreamInfo::Pcm&, cpp::span<const std::byte>) -> bool;
 
-  auto ConfigureSink(const StreamInfo::Pcm&) -> bool;
+  auto ConfigureSink(const StreamInfo::Pcm&, const Duration&) -> bool;
 
   IAudioSource* source_;
   IAudioSink* sink_;
diff --git a/src/codecs/foxenflac.cpp b/src/codecs/foxenflac.cpp
index ce18975c..3a727ce2 100644
--- a/src/codecs/foxenflac.cpp
+++ b/src/codecs/foxenflac.cpp
@@ -6,6 +6,7 @@
 
 #include "foxenflac.hpp"
 #include <stdint.h>
+#include <sys/_stdint.h>
 
 #include <cstdlib>
 
@@ -44,13 +45,20 @@ auto FoxenFlacDecoder::BeginStream(const cpp::span<const std::byte> input)
     return {bytes_used, cpp::fail(Error::kMalformedData)};
   }
 
-  return {bytes_used,
-          OutputFormat{
-              .num_channels = static_cast<uint8_t>(channels),
-              .bits_per_sample = 32,  // libfoxenflac output is fixed-size.
-              .sample_rate_hz = static_cast<uint32_t>(fs),
-              .duration_seconds = {},
-          }};
+  OutputFormat format{
+      .num_channels = static_cast<uint8_t>(channels),
+      .bits_per_sample = 32,  // libfoxenflac output is fixed-size.
+      .sample_rate_hz = static_cast<uint32_t>(fs),
+      .duration_seconds = {},
+      .bits_per_second = {},
+  };
+
+  uint64_t num_samples = fx_flac_get_streaminfo(flac_, FLAC_KEY_N_SAMPLES);
+  if (num_samples > 0) {
+    format.duration_seconds = num_samples / fs;
+  }
+
+  return {bytes_used, format};
 }
 
 auto FoxenFlacDecoder::ContinueStream(cpp::span<const std::byte> input,