RFR: 8337960: Improve performance of mfwrapper by reusing GStreamer media buffers for decoded video

[Alexander Matveev]

On Wed, 5 Feb 2025 03:00:17 GMT, Alexander Matveev <almatvee at openjdk.org> wrote:

> - Added new class `CMFGSTBuffer` which can allocate memory internally or provide GStreamer allocated memory to Media Foundation.
> - Added `GstBufferPool` to limit allocation of output buffers used for rendering (memory will not be allocated for each buffer, but instead will be reused from pool). Limits are 3 min buffers and 6 max buffers. During testing 3 buffers was enough.
> - Changed `CoInitializeEx` to `COINIT_MULTITHREADED` as per Media Foundation requirements.
> - Added error handling for `ProcessOutput` in case of https://bugs.openjdk.org/browse/JDK-8329227. With error handling `MediaPlayer` fails nicely instead of silent hang.

8337960: Improve performance of mfwrapper by reusing GStreamer media buffers for decoded video [v2]
- Fixed typos.
- Lock / Unlock is now thread safe and last Unlock will unmap buffer.
- AllocateOrGetBuffer() is updated to remap unmapped buffer and split into two logical sections.

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PR Comment: https://git.openjdk.org/jfx/pull/1695#issuecomment-2655410557