From 530907d519257b70b2418c3f96e05cd568ec01ae Mon Sep 17 00:00:00 2001
From: Bo-Rong Chen <borongchen@google.com>
Date: Tue, 26 Mar 2024 17:07:46 -0700
Subject: [PATCH] [media] Fix OpusAudioDecoder::Reset() on  PartialAudio tests

This PR (https://github.com/youtube/cobalt/pull/2501) recreating OpusAUdioDecoder in Reset(). Change to reset a previously initialized state using the #OPUS_RESET_STATE CTL as stated in the opus document.

b/327281974
---
 starboard/shared/opus/opus_audio_decoder.cc | 65 +++++++++++----------
 starboard/shared/opus/opus_audio_decoder.h  |  2 -
 2 files changed, 33 insertions(+), 34 deletions(-)

diff --git a/starboard/shared/opus/opus_audio_decoder.cc b/starboard/shared/opus/opus_audio_decoder.cc
index 85ba47e6eb1f..f345f70e9cd5 100644
--- a/starboard/shared/opus/opus_audio_decoder.cc
+++ b/starboard/shared/opus/opus_audio_decoder.cc
@@ -47,11 +47,31 @@ static const VorbisLayout vorbis_mappings[8] = {
 
 OpusAudioDecoder::OpusAudioDecoder(const AudioStreamInfo& audio_stream_info)
     : audio_stream_info_(audio_stream_info) {
-  InitializeCodec();
+  int error;
+  int channels = audio_stream_info_.number_of_channels;
+  if (channels > 8 || channels < 1) {
+    SB_LOG(ERROR) << "Can't create decoder with " << channels << " channels";
+    return;
+  }
+
+  decoder_ = opus_multistream_decoder_create(
+      audio_stream_info_.samples_per_second, channels,
+      vorbis_mappings[channels - 1].nb_streams,
+      vorbis_mappings[channels - 1].nb_coupled_streams,
+      vorbis_mappings[channels - 1].mapping, &error);
+  if (error != OPUS_OK) {
+    SB_LOG(ERROR) << "Failed to create decoder with error: "
+                  << opus_strerror(error);
+    decoder_ = NULL;
+    return;
+  }
+  SB_DCHECK(decoder_ != NULL);
 }
 
 OpusAudioDecoder::~OpusAudioDecoder() {
-  TeardownCodec();
+  if (decoder_) {
+    opus_multistream_decoder_destroy(decoder_);
+  }
 }
 
 void OpusAudioDecoder::Initialize(const OutputCB& output_cb,
@@ -195,34 +215,6 @@ void OpusAudioDecoder::WriteEndOfStream() {
   Schedule(output_cb_);
 }
 
-void OpusAudioDecoder::InitializeCodec() {
-  int error;
-  int channels = audio_stream_info_.number_of_channels;
-  if (channels > 8 || channels < 1) {
-    SB_LOG(ERROR) << "Can't create decoder with " << channels << " channels";
-    return;
-  }
-
-  decoder_ = opus_multistream_decoder_create(
-      audio_stream_info_.samples_per_second, channels,
-      vorbis_mappings[channels - 1].nb_streams,
-      vorbis_mappings[channels - 1].nb_coupled_streams,
-      vorbis_mappings[channels - 1].mapping, &error);
-  if (error != OPUS_OK) {
-    SB_LOG(ERROR) << "Failed to create decoder with error: "
-                  << opus_strerror(error);
-    decoder_ = NULL;
-    return;
-  }
-  SB_DCHECK(decoder_ != NULL);
-}
-
-void OpusAudioDecoder::TeardownCodec() {
-  if (decoder_) {
-    opus_multistream_decoder_destroy(decoder_);
-  }
-}
-
 scoped_refptr<OpusAudioDecoder::DecodedAudio> OpusAudioDecoder::Read(
     int* samples_per_second) {
   SB_DCHECK(BelongsToCurrentThread());
@@ -241,9 +233,18 @@ scoped_refptr<OpusAudioDecoder::DecodedAudio> OpusAudioDecoder::Read(
 void OpusAudioDecoder::Reset() {
   SB_DCHECK(BelongsToCurrentThread());
 
-  TeardownCodec();
-  InitializeCodec();
+  if (decoder_) {
+    int error = opus_multistream_decoder_ctl(decoder_, OPUS_RESET_STATE);
+    if (error != OPUS_OK) {
+      SB_LOG(ERROR) << "Failed to reset decoder with error: "
+                    << opus_strerror(error);
+      decoder_ = NULL;
+      return;
+    }
+    SB_DCHECK(decoder_ != NULL);
+  }
 
+  frames_per_au_ = kMaxOpusFramesPerAU;
   stream_ended_ = false;
   while (!decoded_audios_.empty()) {
     decoded_audios_.pop();
diff --git a/starboard/shared/opus/opus_audio_decoder.h b/starboard/shared/opus/opus_audio_decoder.h
index f16ba245ff9b..7716cc75e064 100644
--- a/starboard/shared/opus/opus_audio_decoder.h
+++ b/starboard/shared/opus/opus_audio_decoder.h
@@ -54,8 +54,6 @@ class OpusAudioDecoder
  private:
   static constexpr int kMinimumBuffersToDecode = 2;
 
-  void InitializeCodec();
-  void TeardownCodec();
   void DecodePendingBuffers();
   bool DecodeInternal(const scoped_refptr<InputBuffer>& input_buffer);
   static const int kMaxOpusFramesPerAU = 9600;