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• How to compile ffmpeg and x264 with thread support for android ?

  18 mai 2017, par Sureshkumar Menon

  i want to compile both x264 and ffmpeg with thread support for ANDROID .FFmpeg and x264 didn’t compile with thread support even after enabling enable-pthreads and enable-threads respectively.

  Both the config.h contains #define HAVE_THREAD 0 and #define HAVE_PTHREADS 0

  1.How to compile with thread support.
  2.Second question is that when i increase the gop size from 1 to some other value encoder returns 0 for certain subsequent frames.This causes a delay more than 3 to 5 seconds in vide playing

• OpenCV 4.5.2 takes a long time (>100ms) to retrieve a single frame from a webcam, C++ on Windows 10

  9 juin 2021, par Mustard Tiger

  I've been having a tough time getting my webcam working quickly with opencv. Frames take a very long time to read, (a recorded average of 124ms across 500 frames) I've tried on three different computers (running Windows 10) with a logitech C922 webcam. The most recent machine I tested on has a Ryzen 9 3950X, with 32gbs of ram ; no lack of power.

  


  Here is the code :

  


  cv::VideoCapture cap = cv::VideoCapture(m_cameraNum);&#xA;&#xA;// Check if camera opened successfully&#xA;if (!cap.isOpened())&#xA;{&#xA;    m_logger->critical("Error opening video stream or file\n\r");&#xA;    return -1;&#xA;}&#xA;&#xA;bool result = true;&#xA;result &amp;= cap.set(cv::CAP_PROP_FRAME_WIDTH, 1280);&#xA;result &amp;= cap.set(cv::CAP_PROP_FRAME_HEIGHT, 720);&#xA;&#xA;bool ready = false;&#xA;std::vector<string> timeLog;&#xA;timeLog.reserve(50000);&#xA;int i = 0;&#xA;&#xA;while (i &lt; 500)&#xA;{&#xA;    auto start = std::chrono::system_clock::now();&#xA;    &#xA;    cv::Mat img;&#xA;    ready = cap.read(img);&#xA;&#xA;    // If the frame is empty, break immediately&#xA;    if (!ready)&#xA;    {&#xA;        timeLog.push_back("continue");&#xA;        continue;&#xA;    }&#xA;&#xA;    i&#x2B;&#x2B;;&#xA;    auto end = std::chrono::system_clock::now();&#xA;    timeLog.push_back(std::to_string(std::chrono::duration_cast(end - start).count()));&#xA;}&#xA;&#xA;for (auto&amp; entry : timeLog)&#xA;    m_logger->info(entry);&#xA;&#xA;cap.release();&#xA;return 0;&#xA;</string>

  


  Notice that I write the elapsed time to a log file at the end of execution. The average time is 124ms for debug and release, and not one instance of "continue" after half a dozen runs.

  


  It doesn't matter if I use USB 2 or USB 3 ports (the camera is USB2) or if I run a debug build or a release build, the log file will show anywhere from 110ms to 130ms of time for each frame. The camera works fine in other app, OBS can get a smooth 1080@30fps or 720@60fps.

  


  Stepping through the debugger and doing a lot of Googling, I've learned the following about my system :

  


  

  • The backend chosen by default is DSHOW. GStreamer and FFMPEG are also available.

  


  • DSHOW uses FFMPEG somehow (it needs the FFMPEG dll) but I cannot use FFMPEG directly through opencv. Attempting to use cv::VideoCapture(m_cameraNum, cv::CAP_FFMPEG) always fails. It seems like Opencv's interface to FFMPEG is only capable of opening video files.

  


  • Microsoft really screwed up camera devices in Windows a few years back, not sure if this is related to my problem.

  


  


  Here's a short list of the fixes I have tried, most taken from older SO posts :

  


  

  • result &= cap.set(cv::CAP_PROP_FRAME_COUNT, 30) ; // Returns false, does nothing

  


  • result &= cap.set(cv::CAP_PROP_CONVERT_RGB, 0) ; // Returns true, does nothing

  


  • result &= cap.set(cv::CAP_PROP_MODE, cv::VideoWriter::fourcc('M', 'J', 'P', 'G')) ; // Returns false, does nothing

  


  • Set registry key from http://alax.info/blog/1693 that should disable the new Windows camera server.

  


  • Updated from 4.5.0 to 4.5.2, no change.

  


  • Asked device manager to find a newer driver, no newer driver found.

  


  


  I'm out of ideas. Any help ?

  


• Decrypting And Combining .ts Audio Files with .m3u8

  30 septembre 2023, par Jonathon

  I have a few thousand .ts AES-128 encrypted audio files with a .key and .m3u8 file.

  



  The key file just contains a key comprised of 44 characters. The .m3ud files appears to be some type of playlist.

  



  #EXTM3U
#EXT-X-ALLOW-CACHE:NO
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-KEY:METHOD=AES-128,URI="http://localhost:[port]/hls/keys/nax_9781843794066.key"
#EXTINF:10,
http://localhost:[port]/filesequence0000000.ts
#EXTINF:10,
etc...


  



  Note that both the key URI and path to the .ts files is now wrong.

  



  Looking around, it appears ffmpeg might work with this format. But I am unsure of the syntax.

  



  How can I decrypt and combine these files ?

  



  I have been playing around with fixing the playlist syntax and figuring out how to use ffmpeg and got to.

  



  ffmpeg -i nax_9781843794066.m3u8 -c copy output.ts
ffmpeg version N-77197-gdf2ce13 Copyright (c) 2000-2015 the FFmpeg developers
built with gcc 5.2.0 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
libavutil      55. 10.100 / 55. 10.100
libavcodec     57. 17.100 / 57. 17.100
libavformat    57. 19.100 / 57. 19.100
libavdevice    57.  0.100 / 57.  0.100
libavfilter     6. 20.100 /  6. 20.100
libswscale      4.  0.100 /  4.  0.100
libswresample   2.  0.101 /  2.  0.101
libpostproc    54.  0.100 / 54.  0.100
[hls,applehttp @ 0000003e6348a660] Error when loading first segment 'filesequence0000000.ts'
nax_9781843794066.m3u8: Invalid data found when processing input


  



  filesequence0000000.ts is the first file, in the same folder. I cannot tell if this is some problem with the encryption or something else.

  



  This is the key file, if it matters : MoOoNvcKlThWBm2T+VzYq9QKZLw7MFUqSyLYjiwquTQ=