3 files changed, 111 insertions, 0 deletions
diff --git a/src/codecs/CMakeLists.txt b/src/codecs/CMakeLists.txt
index 478d4d3f..8502268c 100644
--- a/src/codecs/CMakeLists.txt
+++ b/src/codecs/CMakeLists.txt
@@ -8,3 +8,13 @@ idf_component_register(
   REQUIRES "result" "span" "libmad" "libfoxenflac" "stb_vorbis")
 
 target_compile_options("${COMPONENT_LIB}" PRIVATE ${EXTRA_WARNINGS})
+
+set(OPUS_FIXED_POINT ON)
+set(OPUS_ENABLE_FLOAT_API ON)
+set(OPUS_INSTALL_PKG_CONFIG_MODULE OFF)
+set(OPUS_INSTALL_CMAKE_CONFIG_MODULE OFF)
+
+set(CMAKE_POLICY_DEFAULT_CMP0077 NEW)
+
+add_subdirectory($ENV{PROJ_PATH}/lib/opus ${CMAKE_CURRENT_BINARY_DIR}/opus)
+target_link_libraries(${COMPONENT_LIB} PUBLIC opus)
diff --git a/src/codecs/include/opus.hpp b/src/codecs/include/opus.hpp
new file mode 100644
index 00000000..a5a7d78c
--- /dev/null
+++ b/src/codecs/include/opus.hpp
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <optional>
+#include <string>
+#include <utility>
+
+#include "opus.h"
+#include "span.hpp"
+
+#include "codec.hpp"
+
+namespace codecs {
+
+class XiphOpusDecoder : public ICodec {
+ public:
+  XiphOpusDecoder();
+  ~XiphOpusDecoder();
+
+  /*
+   * Returns the output format for the next frame in the stream. MP3 streams
+   * may represent multiple distinct tracks, with different bitrates, and so we
+   * handle the stream only on a frame-by-frame basis.
+   */
+  auto BeginStream(cpp::span<const std::byte>) -> Result<OutputFormat> override;
+
+  /*
+   * Writes samples for the current frame.
+   */
+  auto ContinueStream(cpp::span<const std::byte> input,
+                      cpp::span<std::byte> output)
+      -> Result<OutputInfo> override;
+
+  auto SeekStream(cpp::span<const std::byte> input, std::size_t target_sample)
+      -> Result<void> override;
+
+ private:
+  OpusDecoder *opus_;
+  float *sample_buffer_;
+  std::size_t sample_buffer_len_;
+}  // namespace codecs
diff --git a/src/codecs/opus.cpp b/src/codecs/opus.cpp
new file mode 100644
index 00000000..2c4291c2
--- /dev/null
+++ b/src/codecs/opus.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "opus.hpp"
+#include <stdint.h>
+#include <sys/_stdint.h>
+
+#include <cstdint>
+#include <cstring>
+#include <optional>
+
+#include "mad.h"
+
+#include "codec.hpp"
+#include "esp_log.h"
+#include "opus.h"
+#include "result.hpp"
+#include "types.hpp"
+
+namespace codecs {
+
+  static constexpr std::size_t kSampleBufferSize = 5760 * sizeof(float);
+
+XiphOpusDecoder::XiphOpusDecoder() {
+  int err;
+  opus_ = opus_decoder_create(48000, 2, &err);
+  assert(err == OPUS_OK);
+}
+XiphOpusDecoder::~XiphOpusDecoder() {
+  opus_decoder_destroy(opus_);
+}
+
+auto XiphOpusDecoder::BeginStream(const cpp::span<const std::byte> input)
+    -> Result<OutputFormat> {}
+
+auto XiphOpusDecoder::ContinueStream(cpp::span<const std::byte> input,
+                                     cpp::span<std::byte> output)
+    -> Result<OutputInfo> {
+  int samples_decoded = opus_decode_float(
+      opus_, reinterpret_cast<const unsigned char*>(input.data()),
+      input.size_bytes(), sample_buffer_, sample_buffer_len_, 0);
+}
+
+auto XiphOpusDecoder::SeekStream(cpp::span<const std::byte> input,
+                                 std::size_t target_sample) -> Result<void> {
+  return {};
+}
+
+}  // namespace codecs