1 files changed, 86 insertions, 0 deletions
diff --git a/externals/oboe/samples/RhythmGame/src/main/cpp/audio/AAssetDataSource.cpp b/externals/oboe/samples/RhythmGame/src/main/cpp/audio/AAssetDataSource.cpp
new file mode 100644
index 0000000000..1c697878c2
--- /dev/null
+++ b/externals/oboe/samples/RhythmGame/src/main/cpp/audio/AAssetDataSource.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <utils/logging.h>
+#include <oboe/Oboe.h>
+
+#include "AAssetDataSource.h"
+
+#if !defined(USE_FFMPEG)
+#error USE_FFMPEG should be defined in app.gradle
+#endif
+
+#if USE_FFMPEG==1
+#include "FFMpegExtractor.h"
+#else
+#include "NDKExtractor.h"
+#endif
+
+
+constexpr int kMaxCompressionRatio { 12 };
+
+AAssetDataSource* AAssetDataSource::newFromCompressedAsset(
+        AAssetManager &assetManager,
+        const char *filename,
+        const AudioProperties targetProperties) {
+
+    AAsset *asset = AAssetManager_open(&assetManager, filename, AASSET_MODE_UNKNOWN);
+    if (!asset) {
+        LOGE("Failed to open asset %s", filename);
+        return nullptr;
+    }
+
+    off_t assetSize = AAsset_getLength(asset);
+    LOGD("Opened %s, size %ld", filename, assetSize);
+
+    // Allocate memory to store the decompressed audio. We don't know the exact
+    // size of the decoded data until after decoding so we make an assumption about the
+    // maximum compression ratio and the decoded sample format (float for FFmpeg, int16 for NDK).
+#if USE_FFMPEG==true
+    const long maximumDataSizeInBytes = kMaxCompressionRatio * assetSize * sizeof(float);
+    auto decodedData = new uint8_t[maximumDataSizeInBytes];
+
+    int64_t bytesDecoded = FFMpegExtractor::decode(asset, decodedData, targetProperties);
+    auto numSamples = bytesDecoded / sizeof(float);
+#else
+    const long maximumDataSizeInBytes = kMaxCompressionRatio * assetSize * sizeof(int16_t);
+    auto decodedData = new uint8_t[maximumDataSizeInBytes];
+
+    int64_t bytesDecoded = NDKExtractor::decode(asset, decodedData, targetProperties);
+    auto numSamples = bytesDecoded / sizeof(int16_t);
+#endif
+
+    // Now we know the exact number of samples we can create a float array to hold the audio data
+    auto outputBuffer = std::make_unique<float[]>(numSamples);
+
+#if USE_FFMPEG==1
+    memcpy(outputBuffer.get(), decodedData, (size_t)bytesDecoded);
+#else
+    // The NDK decoder can only decode to int16, we need to convert to floats
+    oboe::convertPcm16ToFloat(
+            reinterpret_cast<int16_t*>(decodedData),
+            outputBuffer.get(),
+            bytesDecoded / sizeof(int16_t));
+#endif
+
+    delete[] decodedData;
+    AAsset_close(asset);
+
+    return new AAssetDataSource(std::move(outputBuffer),
+            numSamples,
+            targetProperties);
+}