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  • Calling FFMPEG with Boost.Process

    10 février 2016, par CadentOrange

    I'm trying to call FFMPEG from my C++ process to stream video from an IP camera. The FFMPEG command I use is ffmpeg.exe -rtsp_transport tcp -i rtsp://10.0.1.21/ONVIF/MediaInput?profile=1_def_profile4 -f image2pipe -pix_fmt rgb24 -vcodec rawvideo -r 15 -. I've verified this command in the command prompt and it does start a video stream and dumps the frames to stdout. I've also written similar code in Python and it works.

    This is the code I'm using to call FFMPEG with the arguments from the previous paragraph in C++ and read the individual frames from stdout.

    bool build_ffmpeg_arguments(const std::string &uri, std::vector &args)
{
    args.push_back("-rtsp_transport");
    args.push_back("tcp");
    args.push_back("-i");
    args.push_back(uri);
    args.push_back("-f");
    args.push_back("image2pipe");
    args.push_back("-pix_fmt");
    args.push_back("rgb24");
    args.push_back("-vcodec");
    args.push_back("rawvideo");
    args.push_back("-r");
    args.push_back("15");
    args.push_back("-");

    return true;
}


boost::process::child start_ffmpeg(const std::string &uri,
                                   const std::string &ffmpeg_path = "c:\\Tools\\ffmpeg.exe")
{
    std::vector args;
    build_ffmpeg_arguments(uri, args);

    boost::process::context ctx;
    ctx.stdout_behavior = boost::process::capture_stream();
    ctx.stderr_behavior = boost::process::capture_stream();

    return boost::process::launch(ffmpeg_path, args, ctx);
}

bool read_frame(boost::process::pistream &is, int frame_size, std::vector &frame_bytes)
{
    char *buffer = new char[frame_size];

    frame_bytes.clear();
    is.read(buffer, frame_size);
    int bytes_read = is.gcount();
    frame_bytes.assign(buffer, buffer + bytes_read);

//    std::cout << "Is Bad: " << is.bad() << std::endl;
//    std::cout << "Is EOF: " << is.eof() << std::endl;
//    std::cout << "gcount: " << bytes_read << std::endl;

    delete[] buffer;
    if(is.bad() || is.eof() || bytes_read < frame_size)
    {
        //We read in gunk, skip this time.
        is.clear();
        return false;
    }
    else
    {
        return true;
    }
}


//This is where the code is invoked.
BOOST_AUTO_TEST_CASE(test_ffmpeg_stream)
{
    std::string uri = "rtsp://10.0.1.21/ONVIF/MediaInput?profile=1_def_profile4";
    int width = 320;
    int height = 240;
    int bpp = 3;
    int bytes_expected = width * height * 3;
    boost::process::child c = start_ffmpeg(uri);
    boost::process::pistream &is = c.get_stdout();
    boost::process::pistream &err = c.get_stderr();

    std::vector buffer;
    bool result = read_frame(is, bytes_expected, buffer);
    //BOOST_CHECK_EQUAL(true, result);
    std::cout << "Buffer size: " << buffer.size() << std::endl;

    std::string line;
    while (std::getline(err, line))
        std::cout << line << std::endl;
}

    The output from stderr suggests that the parameters could be passed in wrong.

    ffmpeg version 2.8.3 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 5.2.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-l
ibilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enab
le-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --en
able-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --ena
ble-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc
 --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enabl
e-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --ena
ble-decklink --enable-zlib
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
rtsp://10.0.1.21/ONVIF/MediaInput?profile=1_def_profile4: Unknown error

    Is there a way of showing the full command line with arguments that boost::process::launch is calling? Is there anything obvious that I'm doing wrong with boost::process?

    Update:

    Suspecting that it could be the command line arguments being passed in wrong, I've created a dummy executable that prints out the command line arguments it receives. It's a drop-in replacement for ffmpeg.exe purely so that I can see what command lines are being passed. The command line I'm getting is -rtsp_transport tcp -i rtsp://10.0.1.21/ONVIF/MediaInput?profile=1_def_profile4 -f image2pipe -pix_fmt rgb24 -vcodec rawvideo -r 15 -. Manually calling ffmpeg with that command line works as expected. Yet somehow it doesn't work when launched via boost::process.

    ** Solution **

    It looks like I need to set the the environment field of the context. No idea why that fixes the problem, but it does.

    boost::process::context ctx;
ctx.environment = boost::process::self::get_environment();
ctx.stdout_behavior = boost::process::capture_stream();
ctx.stderr_behavior = boost::process::capture_stream();

  • Using ffmpeg to ensure all files have AC3 and AAC available ?

    10 février 2016, par JamieB

    I currently use the following command to convert files to MP4 with AC3:

    ffmpeg.exe -fix_sub_duration -i `"$oldfile`" -vcodec libx264 -map 0:0 -vb 1095k -c:a:0 ac3 -map 0:1 -ac:a:0 6 -b:a:0 1536k -metadata:s:a:0 language=eng -f mp4 -threads auto -y `"$newFile`"

    I'd like to run a batch file across my entire library which would make sure each file has AAC and AC3 available. Is this possible?

  • Is there any alternative sdk for video edtting ithen than FFMPEG ? [on hold]

    10 février 2016, par Sidd

    I have tried a lot by compiling ffmpeg using android ndk but no success. Is there any alternative sdk for video edtting ithen than FFMPEG?

  • ffmpeg gdigrab hidpi mouse capture

    10 février 2016, par gmetax

    Have anyone find out how to capture the correct mouse position with ffmpeg on hidpi monitors ?
    There is an issue (https://trac.ffmpeg.org/ticket/4232) it says it is fixed, but it isn't in the latest build.

  • What are the different ways to generate thumbnail of video in PHP ? [on hold]

    10 février 2016, par Vaidehi

    Is there any alternative for FFMPEG to get Video thumbnails in PHP? Client don't want to use EXEC and other server commands due to security issues. FFMPEG library need EXEC() to be enabled. So I am looking for other alternatives. I am using below code to generate thumbnail of video using PHP. But on server exec() function is disabled due to security reasons. So, I can't use FFMPEG to generate thumbnail.

    ----------------------------
$thumbnail_path = "your_site_domain/media/images/thumbnail/"; 
$second = 1;
$thumbSize="150x150"; 
$videoname="sample_video";

$cmd="{$ffmpeg_installation_path} -i {$video_file_path} -deinterlace -an -ss {$second} -t 00:00:01  -s {$thumbSize} -r 1 -y -vcodec mjpeg -f mjpeg {$path_to_store_generated_thumbnail} 2>&1";
exec($cmd, $output, $retval);
if ($retval)
{
    echo "error in generating video thumbnail";
}
else
{
    echo "Thumbnail generated successfully";
    echo $thumb_path=$thumbnail_path.$videoname.".jpg";
}
-------------------------------

    In my case, video can be of any format like .mp4, .avi, youtube link or any possible video which I am going to upload using php and while uploading I want to generate thumbnail of same. If any solution then please reply me back.

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