Merge pull request #21022 from sivanov-work:async_mfp_demux

G-API: oneVPL Implement asynchronous MFP demux data provider

* Add dummy dmux

* Initial commit for draft versionn

* Demux for low res file works

* Add media source resolver to work over incorrect MIME

* Add MFP Demux logger

* stash changes

* Extend IDataProvider with CodecId, Add troubleshooting info

* Add IDapaProvider dispatcher

* Add ComPtrGuard wrappers

* Add new unit test scope for MFP demux & Add minor changes

* Enhance UTs

* Remove ATL header

* Remove ATL another one

* Fix build

* Add static for some methods

* Initial commit

* Add async demuxing

* Apply tdd idea

* Intro IDataProvider changes: +fetch_bitstream, -fetch_data

* Fix UTs

* Remove IDataProvider::CodecId & Fix EOF hang

* Remove sync demux

* Remove mfp async dependencies

* Remove VPL dependencies from IDataProvider declaration

* Apply comments

* Fix compilation

* Suppress unused warning

* Apply some comments

* Apply some comments

* Apply comments

modules/gapi/include/opencv2/gapi/streaming/onevpl/data_provider_interface.hpp

@@ -7,28 +7,39 @@
 #ifndef GAPI_STREAMING_ONEVPL_ONEVPL_DATA_PROVIDER_INTERFACE_HPP
 #define GAPI_STREAMING_ONEVPL_ONEVPL_DATA_PROVIDER_INTERFACE_HPP
 #include <exception>
+#include <memory>
 #include <string>
 
 #include <opencv2/gapi/own/exports.hpp> // GAPI_EXPORTS
-
 namespace cv {
 namespace gapi {
 namespace wip {
 namespace onevpl {
 
 struct GAPI_EXPORTS DataProviderException : public std::exception {
-    virtual ~DataProviderException() {}
-};
+    DataProviderException(const std::string& descr);
+    DataProviderException(std::string&& descr);
 
-struct GAPI_EXPORTS DataProviderSystemErrorException : public DataProviderException {
-    DataProviderSystemErrorException(int error_code, const std::string& desription = std::string());
-    virtual ~DataProviderSystemErrorException();
+    virtual ~DataProviderException() = default;
     virtual const char* what() const noexcept override;
-
 private:
     std::string reason;
 };
 
+struct GAPI_EXPORTS DataProviderSystemErrorException final : public DataProviderException {
+    DataProviderSystemErrorException(int error_code, const std::string& desription = std::string());
+    ~DataProviderSystemErrorException() = default;
+};
+
+struct GAPI_EXPORTS DataProviderUnsupportedException final : public DataProviderException {
+    DataProviderUnsupportedException(const std::string& description);
+    ~DataProviderUnsupportedException() = default;
+};
+
+struct GAPI_EXPORTS DataProviderImplementationException : public DataProviderException {
+    DataProviderImplementationException(const std::string& description);
+    ~DataProviderImplementationException() = default;
+};
 /**
  * @brief Public interface allows to customize extraction of video stream data
  * used by onevpl::GSource instead of reading stream from file (by default).
@@ -41,21 +52,41 @@ private:
  */
 struct GAPI_EXPORTS IDataProvider {
     using Ptr = std::shared_ptr<IDataProvider>;
+    using mfx_codec_id_type = uint32_t;
 
-    virtual ~IDataProvider() {}
+    /**
+     * NB: here is supposed to be forward declaration of mfxBitstream
+     * But according to current oneVPL implementation it is impossible to forward
+     * declare untagged struct mfxBitstream.
+     *
+     * IDataProvider makes sense only for HAVE_VPL is ON and to keep IDataProvider
+     * interface API/ABI compliant between core library and user application layer
+     * let's introduce wrapper mfx_bitstream which inherits mfxBitstream in private
+     * G-API code section and declare forward for wrapper mfx_bitstream here
+     */
+    struct mfx_bitstream;
+
+    virtual ~IDataProvider() = default;
+
+    /**
+     * The function is used by onevpl::GSource to extract codec id from data
+     *
+     */
+    virtual mfx_codec_id_type get_mfx_codec_id() const = 0;
 
     /**
      * The function is used by onevpl::GSource to extract binary data stream from @ref IDataProvider
      * implementation.
      *
      * It MUST throw `DataProviderException` kind exceptions in fail cases.
-     * It MUST return 0 in EOF which considered as not-fail case.
+     * It MUST return MFX_ERR_MORE_DATA in EOF which considered as not-fail case.
      *
-     * @param out_data_bytes_size the available capacity of out_data buffer.
-     * @param out_data the output consumer buffer with capacity out_data_bytes_size.
-     * @return fetched bytes count.
+     * @param in_out_bitsream the input-output reference on MFX bitstream buffer which MUST be empty at the first request
+     * to allow implementation to allocate it by itself and to return back. Subsequent invocation of `fetch_bitstream_data`
+     * MUST use the previously used in_out_bitsream to avoid skipping rest of frames which haven't been consumed
+     * @return true for fetched data, false on EOF and throws exception on error
      */
-    virtual size_t fetch_data(size_t out_data_bytes_size, void* out_data) = 0;
+    virtual bool fetch_bitstream_data(std::shared_ptr<mfx_bitstream> &in_out_bitsream) = 0;
 
     /**
      * The function is used by onevpl::GSource to check more binary data availability.