Merge "stagefright: add a 2kb cache for CallbackDataSource." (a7346034) · Commits · e / os / android_frameworks_av

media/libstagefright/CallbackDataSource.cpp

+49 −3

Original line number	Diff line number	Diff line
		@@ -70,9 +70,10 @@ ssize_t CallbackDataSource::readAt(off64_t offset, void* data, size_t size) {
		if (numRead == 0) {
		return totalNumRead;
		}
		// Sanity check.
		CHECK((size_t)numRead <= numToRead && numRead >= 0 &&
		(size_t)numRead <= bufferSize);
		if ((size_t)numRead > numToRead) {
		return ERROR_OUT_OF_RANGE;
		}
		CHECK(numRead >= 0 && (size_t)numRead <= bufferSize);
		memcpy(((uint8_t*)data) + totalNumRead, mMemory->pointer(), numRead);
		numLeft -= numRead;
		totalNumRead += numRead;
		@@ -94,4 +95,49 @@ status_t CallbackDataSource::getSize(off64_t *size) {
		return OK;
		}

		TinyCacheSource::TinyCacheSource(const sp<DataSource>& source)
		: mSource(source), mCachedOffset(0), mCachedSize(0) {
		}

		status_t TinyCacheSource::initCheck() const {
		return mSource->initCheck();
		}

		ssize_t TinyCacheSource::readAt(off64_t offset, void* data, size_t size) {
		if (size >= kCacheSize) {
		return mSource->readAt(offset, data, size);
		}

		// Check if the cache satisfies the read.
		if (offset >= mCachedOffset && offset + size <= mCachedOffset + mCachedSize) {
		memcpy(data, &mCache[offset - mCachedOffset], size);
		return size;
		}

		// Fill the cache and copy to the caller.
		const ssize_t numRead = mSource->readAt(offset, mCache, kCacheSize);
		if (numRead <= 0) {
		return numRead;
		}
		if ((size_t)numRead > kCacheSize) {
		return ERROR_OUT_OF_RANGE;
		}

		mCachedSize = numRead;
		mCachedOffset = offset;
		CHECK(mCachedSize <= kCacheSize && mCachedOffset >= 0);
		const size_t numToReturn = std::min(size, (size_t)numRead);
		memcpy(data, mCache, numToReturn);

		return numToReturn;
		}

		status_t TinyCacheSource::getSize(off64_t *size) {
		return mSource->getSize(size);
		}

		uint32_t TinyCacheSource::flags() {
		return mSource->flags();
		}

		} // namespace android

media/libstagefright/DataSource.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -283,7 +283,7 @@ sp<DataSource> DataSource::CreateMediaHTTP(const sp<IMediaHTTPService> &httpServ
		}

		sp<DataSource> DataSource::CreateFromIDataSource(const sp<IDataSource> &source) {
		return new CallbackDataSource(source);
		return new TinyCacheSource(new CallbackDataSource(source));
		}

		String8 DataSource::getMIMEType() const {

media/libstagefright/include/CallbackDataSource.h

+30 −0

Original line number	Diff line number	Diff line
		@@ -44,6 +44,36 @@ private:
		DISALLOW_EVIL_CONSTRUCTORS(CallbackDataSource);
		};


		// A caching DataSource that wraps a CallbackDataSource. For reads smaller
		// than kCacheSize it will read up to kCacheSize ahead and cache it.
		// This reduces the number of binder round trips to the IDataSource and has a significant
		// impact on time taken for filetype sniffing and metadata extraction.
		class TinyCacheSource : public DataSource {
		public:
		TinyCacheSource(const sp<DataSource>& source);

		virtual status_t initCheck() const;
		virtual ssize_t readAt(off64_t offset, void* data, size_t size);
		virtual status_t getSize(off64_t* size);
		virtual uint32_t flags();

		private:
		// 2kb comes from experimenting with the time-to-first-frame from a MediaPlayer
		// with an in-memory MediaDataSource source on a Nexus 5. Beyond 2kb there was
		// no improvement.
		enum {
		kCacheSize = 2048,
		};

		sp<DataSource> mSource;
		uint8_t mCache[kCacheSize];
		off64_t mCachedOffset;
		size_t mCachedSize;

		DISALLOW_EVIL_CONSTRUCTORS(TinyCacheSource);
		};

		}; // namespace android

		#endif // ANDROID_CALLBACKDATASOURCE_H