Android 13 - Media框架（21）- ACodec（三）

这一节我们将继续来学习 ACodec 的剩余部分。

    enum {
        kFlagIsSecure                                 = 1,
        kFlagPushBlankBuffersToNativeWindowOnShutdown = 2,
        kFlagIsGrallocUsageProtected                  = 4,
        kFlagPreregisterMetadataBuffers               = 8,
    };

    enum {
        kVideoGrallocUsage = (GRALLOC_USAGE_HW_TEXTURE
                            | GRALLOC_USAGE_HW_COMPOSER
                            | GRALLOC_USAGE_EXTERNAL_DISP)
                            | static_cast<uint64_t>(BufferUsage::VIDEO_DECODER),
    };

    struct BufferInfo {
        enum Status {
            OWNED_BY_US,
            OWNED_BY_COMPONENT,
            OWNED_BY_UPSTREAM,
            OWNED_BY_DOWNSTREAM,
            OWNED_BY_NATIVE_WINDOW,
            UNRECOGNIZED,            // not a tracked buffer
        };

        static inline Status getSafeStatus(BufferInfo *info) {
            return info == NULL ? UNRECOGNIZED : info->mStatus;
        }

        IOMX::buffer_id mBufferID;
        Status mStatus;
        unsigned mDequeuedAt;

        sp<MediaCodecBuffer> mData;  // the client's buffer; if not using data conversion, this is
                                     // the codec buffer; otherwise, it is allocated separately
        sp<RefBase> mMemRef;         // and a reference to the IMemory, so it does not go away
        sp<MediaCodecBuffer> mCodecData;  // the codec's buffer
        sp<RefBase> mCodecRef;            // and a reference to the IMemory

        sp<GraphicBuffer> mGraphicBuffer;
        bool mNewGraphicBuffer;
        int mFenceFd;
        FrameRenderTracker::Info *mRenderInfo;

        // The following field and 4 methods are used for debugging only
        bool mIsReadFence;
        // Store |fenceFd| and set read/write flag. Log error, if there is already a fence stored.
        void setReadFence(int fenceFd, const char *dbg);
        void setWriteFence(int fenceFd, const char *dbg);
        // Log error, if the current fence is not a read/write fence.
        void checkReadFence(const char *dbg);
        void checkWriteFence(const char *dbg);
    };