* Allow the number of threads FFMpeg uses to be selected during VideoCapture::open().
Reset interupt timer in grab if
err = avformat_find_stream_info(ic, NULL);
is interupted but open is successful.

* Correct the returned number of threads and amend test cases.

* Update container test case.

* Reverse changes added to existing videoio_container test case and include test combining thread change and raw read in the newly added videoio_read test case.

Default FFMPEG VideoCapture backend to rtsp_flags=prefer_tcp

* Make the VideoCapture ffmpeg backends default rtsp connection type prefer_tcp.

* Ensure that the ffmpeg version of avformat is checked.

resolves #21038

* remove C assert

* revert C header

* fix several points in review

* fix test_ds.cpp

Add capacity to Videocapture to return the extraData from FFmpeg when required

* Update rawMode to append any extra data recieved during the initial negotiation of an RTSP stream or during the parsing of an MPEG4 file header.
For h264[5] RTSP streams this ensures the parameter sets if available are always returned on the first call to grab()/read() and has two purposes:
1) To ensure the parameter sets are available even if they are not transmitted in band.  This is common for axis ip camera's.
2) To allow callers of VideoCapture::grab()[read()] to write to split the raw stream over multiple files by appending the parameter sets to the begining of any new files.
For (1) there is no alternative, for (2) if the parameter sets were provided in band it would be possible to parse the raw bit stream and search for the parameter sets however that would be a lot of work when that information is already provided by FFMPEG.
For MPEG4 files this information is only suplied in the header and is required for decoding.

Two properties are also required to enable the raw encoded bitstream to be written to multiple files, these are;
1) an indicator as to whether the last frame was a key frame or not - each new file needs to start at a key frame to avoid storing unusable frame diffs,
2) the length in bytes of the paramater sets contained in the last frame - required to split the paramater sets from the frame without having to parse the stream.  Any call to VideoCapture::get(CAP_PROP_LF_PARAM_SET_LEN) returning a number greater than zero indicates the presense of a parameter set at the begining of the raw bitstream.

* Adjust test data to account for extraData

* Address warning.

* Change added property names and remove paramater set start code check.

* Output extra data on calls to retrieve instead of appending to the first packet.

* Reverted old test case and added new one to evaluate new functionality.

* Add missing definition.

* Remove flag from legacy api.
Add property to determine if returning extra data is supported.
Always allow extra data to be returned on calls to cap.retrieve()
Update test case.

* Update condition which indicates CAP_PROP_CODEC_EXTRADATA_INDEX is not supported in test case.

* Include compatibility for windows dll if not updated.
Enforce existing return status convention.

* Fix return error and missing test constraints.

Fix the following build failure with gcc 4.8:

In file included from /home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/videoio/src/cap_ffmpeg_impl.hpp:100:0,
                 from /home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/videoio/src/cap_ffmpeg.cpp:50:
/home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/videoio/src/cap_ffmpeg_hw.hpp: In constructor 'HWAccelIterator::HWAccelIterator(cv::VideoAccelerationType, bool, AVDictionary*)':
/home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/videoio/src/cap_ffmpeg_hw.hpp:939:23: error: use of deleted function 'std::basic_istringstream<char>& std::basic_istringstream<char>::operator=(const std::basic_istringstream<char>&)'
             s_stream_ = std::istringstream(accel_list);
                       ^
In file included from /home/buildroot/autobuild/instance-3/output-1/host/opt/ext-toolchain/arm-none-linux-gnueabi/include/c++/4.8.3/complex:45:0,
                 from /home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/core/include/opencv2/core/cvstd.inl.hpp:47,
                 from /home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/core/include/opencv2/core.hpp:3306,
                 from /home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/videoio/include/opencv2/videoio.hpp:46,
                 from /home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/videoio/src/precomp.hpp:57,
                 from /home/buildroot/autobuild/instance-3/output-1/build/opencv4-4.5.4/modules/videoio/src/cap_ffmpeg.cpp:42:
/home/buildroot/autobuild/instance-3/output-1/host/opt/ext-toolchain/arm-none-linux-gnueabi/include/c++/4.8.3/sstream:272:11: note: 'std::basic_istringstream<char>& std::basic_istringstream<char>::operator=(const std::basic_istringstream<char>&)' is implicitly deleted because the default definition would be ill-formed:
     class basic_istringstream : public basic_istream<_CharT, _Traits>
           ^
/home/buildroot/autobuild/instance-3/output-1/host/opt/ext-toolchain/arm-none-linux-gnueabi/include/c++/4.8.3/sstream:272:11: error: use of deleted function 'std::basic_istream<char>& std::basic_istream<char>::operator=(const std::basic_istream<char>&)'

Fixes:
 - http://autobuild.buildroot.org/results/60f8846b435dafda0ced412d59ffe15bdff0810dSigned-off-by: NFabrice Fontaine <fontaine.fabrice@gmail.com>

Add CAP_PROP_STREAM_OPEN_TIME

* Added CAP_PROP_STREAM_OPEN_TIME to videoio module - can be used to query the time at which the stream was opened, in seconds since Jan 1 1970 (midnight, UTC). Useful for RTSP and other live video where absolute timestamps are needed. Only applicable to ffmpeg backends

* use nanoseconds instead of seconds to mark the stream open time, and change the cap prop name to CAP_PROP_STREAM_OPEN_TIME_NSEC

* use microseconds for CAP_PROP_STREAM_OPEN_TIME (nanoseconds rolls over too soon, and milliseconds/seconds requires a division)

* fix whitespace issue

* VideoCapture add open/read timeout params to FFMPEG backend

* Fix wrong enum name

* Fix wrong enum name

* VideoCapture timeout set/get

* Common formatting for enum values

* Fix enum values wrongly in videoio.hpp

* Define timeout enum values in public api and align with master

cv::UMat output/input in VideoCapture/VideoWriter (data stays in GPU memory)

* FFMPEG with UMat input/output

* OpenCL_D3D* context

* fix Linux build

* cosmetic changes

* fix build if USE_AV_HW_CODECS=0

* simplify how child context pointer stored in parent context

* QSV interop with OpenCL on Windows

* detect_msdk.cmake via pkg-config

* fix av_buffer_ref() usage

* revert windows-decode-mfx whitelisting; remove debug msg

* address review comments

* rename property to HW_ACCELERATION_USE_OPENCL

* fix issue with "cl_khr_d3d11_sharing" extension not reported by OpenCL GPU+CPU platform

* core(ocl): add OpenCL stubs for configurations without OpenCL

* videoio(ffmpeg): update #if guards

* Put OpenCL related code under HAVE_OPENCL; simplify reuse of media context from OpenCL context

* videoio(test): skip unsupported tests

- plugins don't support OpenCL/UMat yet
- change handling of *_USE_OPENCL flag

* videoio(ffmpeg): OpenCL dependency

* videoio(ffmpeg): MediaSDK/oneVPL dependency

* cleanup, logging

* cmake: fix handling of 3rdparty interface targets
Co-authored-by: NAlexander Alekhin <alexander.a.alekhin@gmail.com>

- default is VIDEO_ACCELERATION_NONE

* videoio(ffmpeg): eliminate MSVC build warnings

* videoio(ffmpeg): update initialization code

- repair FFmpeg logger settings on each .open() call

videoio: HW decode/encode in FFMPEG backend; new properties with support in FFMPEG/GST/MSMF

* HW acceleration in FFMPEG backend

* fixes on Windows, remove D3D9

* HW acceleration in FFMPEG backend

* fixes on Windows, remove D3D9

* improve va test

* Copyright

* check LIBAVUTIL_BUILD >= AV_VERSION_INT(55, 78, 100) // FFMPEG 3.4+

* CAP_MSMF test on .mp4

* .mp4 in test

* improve va test

* Copyright

* check LIBAVUTIL_BUILD >= AV_VERSION_INT(55, 78, 100) // FFMPEG 3.4+

* CAP_MSMF test on .mp4

* .mp4 in test

* .avi for GStreamer test

* revert changes around seek()

* cv_writer_open_with_params

* params.warnUnusedParameters

* VideoCaptureParameters in GStreamer

* open_with_params

* params->getUnused

* Reduce PSNR threshold 33->32 (other tests use 30)

* require FFMPEG 4.0+; PSNR 30 as in other tests

* GStreamer AVI-demux plugin not installed in Ubuntu test environment?

* fix build on very old ffmpeg

* fix build on very old ffmpeg

* fix build issues

* fix build issues (static_cast)

* FFMPEG built on Windows without H264 encoder?

* fix for write_nothing test on VAAPI

* fix warnings

* fix cv_writer_get_prop in plugins

* use avcodec_get_hw_frames_parameters; more robust fallback to SW codecs

* internal function hw_check_device() for device check/logging

* two separate tests for HW read and write

* image size 640x480 in encode test

* WITH_VA=ON (only .h headers used in OpenCV, no linkage dependency)

* exception on VP9 SW encoder?

* rebase master; refine info message

* videoio: fix FFmpeg standalone plugin build

* videoio(ffmpeg): eliminate MSVC build warnings

* address review comments

* videoio(hw): update videocapture_acceleration.read test

- remove parallel decoding by SW code path
- check PSNR against the original generated image

* videoio: minor fixes

* videoio(test): disable unsupported MSMF cases (SW and HW)

* videoio(test): update PSNR thresholds for HW acceleration read

* videoio(test): update debug messages

* "hw_acceleration" whitelisting parameter

* little optimization in test

* D3D11VA supports decoders, doesn't support encoders

* videoio(test): adjust PSNR threshold in write_read_position tests

* videoio(ffmpeg): fix rejecting on acceleration device name mismatch

* videoio(ffmpeg): fix compilation USE_AV_HW_CODECS=0, add more debug logging

* videoio: rework VideoAccelerationType behavior

- enum is not a bitset
- default value is backend specific
- only '_NONE' and '_ANY' may fallback on software processing
- specific H/W acceleration doesn't fallback on software processing. It fails if there is no support for specified H/W acceleration.

* videoio(test): fix for current FFmpeg wrapper
Co-authored-by: NAlexander Alekhin <alexander.a.alekhin@gmail.com>

- example: ffmpeg

 - AVDISCARD_NONINTRA flag is supported only for FFMPEG libraries pack

Remove obsolete FFMPEG versions support

* refactor: removed obsolete FFMPEG version support

 - Oldest available version via official FFMPEG repository mirror has tag v.0.5
 LIBAVFORMAT version for this tag is 52.31.0

* refactor: prefer std::min function to MIN macro

* refactor: use appropriate macro instead of manual version calculation

* refactor: remove macros for versions prior 0.5.15 release

* refactor: remove libavcodec macros for versions < 54.35.1 (default to Ubuntu 14.04)

* refactor: remove libavformat macro for versions < 54.20.4 (default ubuntu 14.04)

* refactor: remove libavutil macro for versions < 52.3.0 (default ubuntu 14.04)

* refactor: remove missed macros for libavcodec and libavformat

* refactor: remove unused _opencv_ffmpeg_free function

* build: add FFMPEG libraries versions checks

 - Add verbose message about what FFMPEG libraries are missing.
 - Add minimal versions check set to libav 9.20 release (default ubuntu 14.04) and FFMPEG 1.1.16 release.
   If the check is failed CMake produces user-friendly message instead of build error.

* fix: libavcodec version guard for AVDISCARD_NONINTRA

* fix: libav check of libavcodec version guard for AVDISCARD_NONINTRA

* fix: version check for AV_CODEC_FLAG_GLOBAL_HEADER

* fix: missing FFMPEG libraries output

- Added test for automated rotation for  MP4 videos with metadata
- Fix 180 degrees rotation bug
- Moved rotation logic to cv::VideoCapture implementation for FFmpeg and restore binary compatibility with FFmpeg wrapper.

- Add VideoCapture camera orientation property for mp4 videos with camera orientation meta.
- Add auto rotation for 90, 180, 270 degrees using cv::rotate

decoder should be properly flushed after that

* feature: Add video capture bitrate read-only property for FFMPEG backend

* test: For WIN32 property should be either expected or 0.

Added `IsOneOf` helper function, enabled only for _WIN32.

Videocapture skip frames

* enable skipping frames

* update videoio_skip test

- backport 15290
- add extra test case

Add retrieve encoded frame to VideoCapture

* Add capacity to retrieve the encoded frame from a VideoCapture object.

* Correct raw codec and pixle format output from ffmpeg capture.

* Remove warnings from build.

* Added VideoCaptureRaw subclass.

* Include abstract base class VideoCaptureBase and rename new subclass VideoContainer as suggested by mshabunin.

* Remove using.

* Change base class name for compatibility with jave bindings generator.

* Move grab and retrieve and add override specifier

* Add setRaw and readRaw to IVideoCapture interface
-setRaw to disable video decoding and enable bitstream filters from mp4 to h254 and h265.
-readRaw to return the raw undecoded/filtered bitstream.
Add createRawCapture to initiate a backend with setRaw enabled.
Remove inheritance and use an independant VideoContainer subclass with IVideoCapture member.

* Address unused parameter warings.
Remove VideoContainer from python bindings as it no longer returns a Mat.
Use opencv type uchar instead of unsigned char.
Add missing destructor to VideoContainer class.

* Address build warnings and include all params in documentation.

* Include deprecated bitstream filtering API.

* Update codec_id query to work with older ffmpeg api's.
Change api version defines to be consistent - most recent api version first.

* Fix typo.

* Update test to work with naming of new files in the extra repo

* Investigate test failure

* Check bytes read by ffmpeg

* Removed mp4 video container test

* Applied suggested changes.

* videoio: rework API for extraction of RAW video streams

- FFmpeg only

* address review comments