WIP Audio decoder

Remove some old comments

src/xenia/apu/audio_decoder.h

@@ -0,0 +1,67 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2015 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_APU_AUDIO_DECODER_H_
+#define XENIA_APU_AUDIO_DECODER_H_
+
+#include "xenia/apu/audio_system.h"
+
+// XMA audio format:
+// From research, XMA appears to be based on WMA Pro with
+// a few (very slight) modifications.
+// XMA2 is fully backwards-compatible with XMA1.
+
+// Helpful resources:
+// https://github.com/koolkdev/libertyv/blob/master/libav_wrapper/xma2dec.c
+// http://hcs64.com/mboard/forum.php?showthread=14818
+// https://github.com/hrydgard/minidx9/blob/master/Include/xma2defs.h
+
+// Forward declarations
+struct AVCodec;
+struct AVCodecContext;
+struct AVFrame;
+struct AVPacket;
+
+namespace xe {
+namespace apu {
+
+class AudioDecoder {
+  public:
+    AudioDecoder();
+    ~AudioDecoder();
+
+    int Initialize(int bits);
+    void Cleanup();
+
+    int PreparePacket(uint8_t* input, size_t size, int sample_rate, int channels);
+    void DiscardPacket();
+
+    int DecodePacket(uint8_t* output, size_t offset, size_t size);
+
+  private:
+    AVCodec* codec_;
+    AVCodecContext* context_;
+    AVFrame* decoded_frame_;
+    AVPacket* packet_;
+
+    uint8_t bits_per_frame_;
+    uint32_t bits_;
+    size_t current_frame_pos_;
+    uint8_t* current_frame_;
+    uint32_t frame_samples_size_;
+    int offset_;
+
+    uint8_t packet_data_[XMAContextData::kBytesPerBlock];
+};
+
+} // namespace apu
+} // namespace xe
+
+
+#endif  // XENIA_APU_AUDIO_DECODER_H_