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  • avcodec/speedhq : Don't use ff_ prefix for static symbols

    12 octobre 2020, par Andreas Rheinhardt
    avcodec/speedhq : Don't use ff_ prefix for static symbols
    

    Reviewed-by : Paul B Mahol <onemda@gmail.com>
    Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

    • [DH] libavcodec/speedhq.c
  • How do I make a C# win form program that breaks a video down to frames, then put those frames back together to make a video ?

    30 juillet 2015, par Atom Scott

    First, I’m fairly new to C sharp so I’m looking for a thorough and easy to understand answer.

    How do I make a C# win form program that breaks a video down to frames, then puts those frames back together to make a video ?
    I also want to be able to select which frames to extract by setting an interval time. For example, extract frames that are one second apart.
    Is this possible, I have done some research but I don’t understand how to use the codes displayed on the following websites.

    Supposedly code to breakdown video into frames. However I do not know where to put it. Do I make it the event for a button or something. From my own research I am guessing this uses ffmpeg. But I’m not exactly sure how to use ffmpeg, I have tried downloading Aforge, and use Aforge.Video.ffmpeg. But I’m stuck there.
    http://www.researchgate.net/post/Has_anyone_code_in_C_to_read_video_file_and_split_it_into_frames[^]

    Code for making a video from images, it looked promising so i tried to copy and paste it visual studio. However the line using BytescoutImageToVideoLib ; has an error asking me whether I am missing a reference. What reference am I missing ?
    http://bytescout.com/products/developer/imagetovideosdk/imagetovideosdk_first_step_with_visual_c_sharp_net.html[^]

    I also noticed that there was a page on code project for something similar to this, but the downloadable demo project didn’t work at all. I didnt see the point in spending time on something where the end product is broken.
    http://www.codeproject.com/Articles/13237/Extract-Frames-from-Video-Files

    Any help is greatly appreciated.

  • Compile FFmpeg Zeranoe Build with Visual Studio 2013

    29 août 2017, par mFeinstein

    I downloaded the most recent Zeranoe dev build here, included the header files to my code, placed extern "C" around the includes, since this is a C++ project and FFmpeg is a C library, and added the libs to Visual Studio as well, and I get this linker error :

    1>Camera.obj : error LNK2019 : unresolved external symbol _av_free referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _av_freep referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _av_frame_alloc referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _av_frame_free referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_register_all referenced in function __catch$ ??0Camera@MicroDFV_Camera@@QAE@V ?$basic_string@DU ?$char_traits@D@std@@V ?$allocator@D@2@@std@@0PAX@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_alloc_context3 referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_open2 referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_close referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _av_init_packet referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _av_packet_unref referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_find_encoder referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _avcodec_encode_video2 referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _av_opt_set referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>Camera.obj : error LNK2019 : unresolved external symbol _av_image_alloc referenced in function __catch$ ?NewFrameReceived@Camera@MicroDFV_Camera@@AAEXKKKGPAE@Z$0
    1>M :\Desktop\OpenCVTest\Debug\OpenCVTest.exe : fatal error LNK1120 : 14 unresolved externals

    Searching here and on Google I found many recommendations, such as to add #pragma comment(lib,...), and that the libs are static, so their order is important, and none of this helps.

    So I scratched my head even more and realized that the Zeranoe build is made with MinGW-w64, so probably it won’t link with Visual Studio. I inspected the lib using dumpbin and the symbols on the libs don’t have the underscore, so I am pretty sure it won’t work.

    The other Zeranoe builds for Windows don’t have libs, they are just plain .exe or exe + .dll.

    Will I have to make my own VS2013 build of FFmpeg to link it, or is there some alternative way ?