Some work to make audio encoding work.

1 files changed, 100 insertions, 0 deletions

diff --git a/cmds/stagefright/SineSource.cpp b/cmds/stagefright/SineSource.cpp
new file mode 100644
index 0000000..3c25a7f
--- /dev/null
+++ b/cmds/stagefright/SineSource.cpp
@@ -0,0 +1,100 @@
+#include "SineSource.h"
+
+#include <math.h>
+
+#include <media/stagefright/MediaBufferGroup.h>
+#include <media/stagefright/MediaDebug.h>
+#include <media/stagefright/MetaData.h>
+
+namespace android {
+
+SineSource::SineSource(int32_t sampleRate, int32_t numChannels)
+    : mStarted(false),
+      mSampleRate(sampleRate),
+      mNumChannels(numChannels),
+      mPhase(0),
+      mGroup(NULL) {
+    CHECK(numChannels == 1 || numChannels == 2);
+}
+
+SineSource::~SineSource() {
+    if (mStarted) {
+        stop();
+    }
+}
+
+status_t SineSource::start(MetaData *params) {
+    CHECK(!mStarted);
+
+    mGroup = new MediaBufferGroup;
+    mGroup->add_buffer(new MediaBuffer(kBufferSize));
+
+    mPhase = 0;
+    mStarted = true;
+
+    return OK;
+}
+
+status_t SineSource::stop() {
+    CHECK(mStarted);
+
+    delete mGroup;
+    mGroup = NULL;
+
+    mStarted = false;
+
+    return OK;
+}
+
+sp<MetaData> SineSource::getFormat() {
+    sp<MetaData> meta = new MetaData;
+    meta->setCString(kKeyMIMEType, "audio/raw");
+    meta->setInt32(kKeyChannelCount, mNumChannels);
+    meta->setInt32(kKeySampleRate, mSampleRate);
+
+    return meta;
+}
+
+status_t SineSource::read(
+        MediaBuffer **out, const ReadOptions *options) {
+    *out = NULL;
+
+    MediaBuffer *buffer;
+    status_t err = mGroup->acquire_buffer(&buffer);
+
+    if (err != OK) {
+        return err;
+    }
+
+    size_t frameSize = mNumChannels * sizeof(int16_t);
+    size_t numFramesPerBuffer = buffer->size() / frameSize;
+
+    int16_t *ptr = (int16_t *)buffer->data();
+
+    const double k = kFrequency / mSampleRate * (2.0 * M_PI);
+
+    double x = mPhase * k;
+    for (size_t i = 0; i < numFramesPerBuffer; ++i) {
+        int16_t amplitude = (int16_t)(32767.0 * sin(x));
+        
+        *ptr++ = amplitude;
+        if (mNumChannels == 2) {
+            *ptr++ = amplitude;
+        }
+
+        x += k;
+    }
+
+    buffer->meta_data()->setInt32(kKeyTimeUnits, mPhase);
+    buffer->meta_data()->setInt32(kKeyTimeScale, mSampleRate);
+
+    mPhase += numFramesPerBuffer;
+
+    buffer->set_range(0, numFramesPerBuffer * frameSize);
+
+    *out = buffer;
+
+    return OK;
+}
+
+}  // namespace android