Added VideoSourceDownSampler

VideoSourceDownSampler takes in a real video source. The MediaSource
interface is then implemented by shortcircuiting calls to this real source,
except for the read() function. For read we first call read of the real
source, then downsample the frame to the desired size and return that.

Change-Id: I6e1b377e043e136a70a7b03792eb9165bbe26398

2 files changed, 143 insertions, 0 deletions

diff --git a/media/libstagefright/Android.mk b/media/libstagefright/Android.mk
index 6b7947e..0d11b33 100644
--- a/media/libstagefright/Android.mk
+++ b/media/libstagefright/Android.mk
@@ -11,6 +11,7 @@ LOCAL_SRC_FILES:=                         \
         AwesomePlayer.cpp                 \
         CameraSource.cpp                  \
         CameraSourceTimeLapse.cpp         \
+        VideoSourceDownSampler.cpp        \
         DataSource.cpp                    \
         ESDS.cpp                          \
         FileSource.cpp                    \
diff --git a/media/libstagefright/VideoSourceDownSampler.cpp b/media/libstagefright/VideoSourceDownSampler.cpp
new file mode 100644
index 0000000..ea7b09a
--- /dev/null
+++ b/media/libstagefright/VideoSourceDownSampler.cpp
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "VideoSourceDownSampler"
+
+#include <media/stagefright/VideoSourceDownSampler.h>
+#include <media/stagefright/MediaBuffer.h>
+#include <media/stagefright/MediaDebug.h>
+#include <media/stagefright/MetaData.h>
+#include <media/stagefright/YUVImage.h>
+#include <media/stagefright/YUVCanvas.h>
+#include "OMX_Video.h"
+
+namespace android {
+
+VideoSourceDownSampler::VideoSourceDownSampler(const sp<MediaSource> &videoSource,
+        int32_t width, int32_t height) {
+    LOGV("Construct VideoSourceDownSampler");
+    CHECK(width > 0);
+    CHECK(height > 0);
+
+    mRealVideoSource = videoSource;
+    mWidth = width;
+    mHeight = height;
+
+    mMeta = new MetaData(*(mRealVideoSource->getFormat()));
+    CHECK(mMeta->findInt32(kKeyWidth, &mRealSourceWidth));
+    CHECK(mMeta->findInt32(kKeyHeight, &mRealSourceHeight));
+
+    if ((mWidth != mRealSourceWidth) || (mHeight != mRealSourceHeight)) {
+        // Change meta data for width and height.
+        CHECK(mWidth <= mRealSourceWidth);
+        CHECK(mHeight <= mRealSourceHeight);
+
+        mNeedDownSampling = true;
+        computeDownSamplingParameters();
+        mMeta->setInt32(kKeyWidth, mWidth);
+        mMeta->setInt32(kKeyHeight, mHeight);
+    } else {
+        mNeedDownSampling = false;
+    }
+}
+
+VideoSourceDownSampler::~VideoSourceDownSampler() {
+}
+
+void VideoSourceDownSampler::computeDownSamplingParameters() {
+    mDownSampleSkipX = mRealSourceWidth / mWidth;
+    mDownSampleSkipY = mRealSourceHeight / mHeight;
+
+    mDownSampleOffsetX = mRealSourceWidth - mDownSampleSkipX * mWidth;
+    mDownSampleOffsetY = mRealSourceHeight - mDownSampleSkipY * mHeight;
+}
+
+void VideoSourceDownSampler::downSampleYUVImage(
+        const MediaBuffer &sourceBuffer, MediaBuffer **buffer) const {
+    // find the YUV format
+    int32_t srcFormat;
+    CHECK(mMeta->findInt32(kKeyColorFormat, &srcFormat));
+    YUVImage::YUVFormat yuvFormat;
+    if (srcFormat == OMX_COLOR_FormatYUV420SemiPlanar) {
+        yuvFormat = YUVImage::YUV420SemiPlanar;
+    } else if (srcFormat == OMX_COLOR_FormatYUV420Planar) {
+        yuvFormat = YUVImage::YUV420Planar;
+    }
+
+    // allocate mediaBuffer for down sampled image and setup a canvas.
+    *buffer = new MediaBuffer(YUVImage::bufferSize(yuvFormat, mWidth, mHeight));
+    YUVImage yuvDownSampledImage(yuvFormat,
+            mWidth, mHeight,
+            (uint8_t *)(*buffer)->data());
+    YUVCanvas yuvCanvasDownSample(yuvDownSampledImage);
+
+    YUVImage yuvImageSource(yuvFormat,
+            mRealSourceWidth, mRealSourceHeight,
+            (uint8_t *)sourceBuffer.data());
+    yuvCanvasDownSample.downsample(mDownSampleOffsetX, mDownSampleOffsetY,
+            mDownSampleSkipX, mDownSampleSkipY,
+            yuvImageSource);
+}
+
+status_t VideoSourceDownSampler::start(MetaData *params) {
+    LOGV("start");
+    return mRealVideoSource->start();
+}
+
+status_t VideoSourceDownSampler::stop() {
+    LOGV("stop");
+    return mRealVideoSource->stop();
+}
+
+sp<MetaData> VideoSourceDownSampler::getFormat() {
+    LOGV("getFormat");
+    return mMeta;
+}
+
+status_t VideoSourceDownSampler::read(
+        MediaBuffer **buffer, const ReadOptions *options) {
+    LOGV("read");
+    MediaBuffer *realBuffer;
+    status_t err = mRealVideoSource->read(&realBuffer, options);
+
+    if (mNeedDownSampling) {
+        downSampleYUVImage(*realBuffer, buffer);
+
+        int64_t frameTime;
+        realBuffer->meta_data()->findInt64(kKeyTime, &frameTime);
+        (*buffer)->meta_data()->setInt64(kKeyTime, frameTime);
+
+        // We just want this buffer to be deleted when the encoder releases it.
+        // So don't add a reference to it and set the observer to NULL.
+        (*buffer)->setObserver(NULL);
+
+        // The original buffer is no longer required. Release it.
+        realBuffer->release();
+    } else {
+        *buffer = realBuffer;
+    }
+
+    return err;
+}
+
+status_t VideoSourceDownSampler::pause() {
+    LOGV("pause");
+    return mRealVideoSource->pause();
+}
+
+}  // namespace android