5 files changed, 26 insertions, 4 deletions
diff --git a/src/codecs/foxenflac.cpp b/src/codecs/foxenflac.cpp
index eef8225a..b1ba348a 100644
--- a/src/codecs/foxenflac.cpp
+++ b/src/codecs/foxenflac.cpp
@@ -64,7 +64,7 @@ auto FoxenFlacDecoder::OpenStream(std::shared_ptr<IStream> input)
 
   uint64_t num_samples = fx_flac_get_streaminfo(flac_, FLAC_KEY_N_SAMPLES);
   if (num_samples > 0) {
-    format.duration_seconds = num_samples / fs;
+    format.total_samples = num_samples / fs;
   }
 
   return format;
diff --git a/src/codecs/include/codec.hpp b/src/codecs/include/codec.hpp
index ece3d4fe..2f95389c 100644
--- a/src/codecs/include/codec.hpp
+++ b/src/codecs/include/codec.hpp
@@ -91,7 +91,7 @@ class ICodec {
   struct OutputFormat {
     uint8_t num_channels;
     uint32_t sample_rate_hz;
-    std::optional<uint32_t> duration_seconds;
+    std::optional<uint32_t> total_samples;
 
     bool operator==(const OutputFormat&) const = default;
   };
diff --git a/src/codecs/mad.cpp b/src/codecs/mad.cpp
index ce3a9cac..dfa568d4 100644
--- a/src/codecs/mad.cpp
+++ b/src/codecs/mad.cpp
@@ -92,7 +92,7 @@ auto MadMp3Decoder::OpenStream(std::shared_ptr<IStream> input)
 
   auto vbr_length = GetVbrLength(header);
   if (vbr_length) {
-    output.duration_seconds = vbr_length;
+    output.total_samples = vbr_length;
   }
   return output;
 }
@@ -234,7 +234,7 @@ auto MadMp3Decoder::GetVbrLength(const mad_header& header)
     return {};
   }
 
-  return (double)(frames_count * samples_per_frame) / header.samplerate;
+  return (double)(frames_count * samples_per_frame);
 }
 
 }  // namespace codecs
diff --git a/src/codecs/opus.cpp b/src/codecs/opus.cpp
index c0727c6b..f5ff471a 100644
--- a/src/codecs/opus.cpp
+++ b/src/codecs/opus.cpp
@@ -122,9 +122,24 @@ auto XiphOpusDecoder::OpenStream(std::shared_ptr<IStream> input)
     return cpp::fail(Error::kMalformedData);
   }
 
+  auto l = op_pcm_total(opus_, -1);
+  std::optional<uint32_t> length;
+  if (l > 0) {
+    // Output is always downmixed to two channels, but the pcm count does not
+    // reflect this.
+    int channels = op_channel_count(opus_, -1);
+    if (channels == 1) {
+      l *= 2;
+    } else if (channels > 2) {
+      l /= channels * 2;
+    }
+    length = l;
+  }
+
   return OutputFormat{
       .num_channels = 2,
       .sample_rate_hz = 48000,
+      .total_samples = length,
   };
 }
 
diff --git a/src/codecs/vorbis.cpp b/src/codecs/vorbis.cpp
index aa367e02..cf783978 100644
--- a/src/codecs/vorbis.cpp
+++ b/src/codecs/vorbis.cpp
@@ -118,9 +118,16 @@ auto TremorVorbisDecoder::OpenStream(std::shared_ptr<IStream> input)
     return cpp::fail(Error::kMalformedData);
   }
 
+  auto l = ov_pcm_total(&vorbis_, -1);
+  std::optional<uint32_t> length;
+  if (l > 0) {
+    length = l;
+  }
+
   return OutputFormat{
       .num_channels = static_cast<uint8_t>(info->channels),
       .sample_rate_hz = static_cast<uint32_t>(info->rate),
+      .total_samples = length,
   };
 }