Для этого вам необходимо использовать модуль libvlc imem. Это может быть действительно запутанным, поскольку он не является публично документированным API прямо сейчас. Однако я последовал за несколькими другими сообщениями, связанными с этим здесь и на форумах VideoLan. Ниже приведен пример кода, который я сегодня работал на C++, который использует изображения JPEG, загруженные в память, для создания видеопотока. Вы можете выполнить аналогичные шаги, но вам просто нужно будет изменить кодек ваших данных в памяти (см. Строку imem-codec = RV24).
// Local file/media source.
std::string IMEM_SOURCE_FOLDER = "settings/rvideo/samples/bigdog";
class MyImemData
{
public:
MyImemData() : mFrame(0), mDts(0), mPts(0) {}
~MyImemData() {}
std::vector<cv::Mat> mImages;
std::size_t mFrame;
int64_t mDts;
int64_t mPts;
};
/**
\brief Callback method triggered by VLC to get image data from
a custom memory source. This is used to tell VLC where the
data is and to allocate buffers as needed.
To set this callback, use the "--imem-get=<memory_address>"
option, with memory_address the address of this function in memory.
When using IMEM, be sure to indicate the format for your data
using "--imem-cat=2" where 2 is video. Other options for categories are
0 = Unknown,
1 = Audio,
2 = Video,
3 = Subtitle,
4 = Data
When creating your media instance, use libvlc_media_new_location and
set the location to "imem:/" and then play.
\param[in] data Pointer to user-defined data, this is your data that
you set by passing the "--imem-data=<memory_address>" option when
initializing VLC instance.
\param[in] cookie A user defined string. This works the same way as
data, but for string. You set it by adding the "--imem-cookie=<your_string>"
option when you initialize VLC. Use this when multiple VLC instances are
running.
\param[out] dts The decode timestamp, value is in microseconds. This value
is the time when the frame was decoded/generated. For example, 30 fps
video would be every 33 ms, so values would be 0, 33333, 66666, 99999, etc.
\param[out] pts The presentation timestamp, value is in microseconds. This
value tells the receiver when to present the frame. For example, 30 fps
video would be every 33 ms, so values would be 0, 33333, 66666, 99999, etc.
\param[out] flags Unused,ignore.
\param[out] bufferSize Use this to set the size of the buffer in bytes.
\param[out] buffer Change to point to your encoded frame/audio/video data.
The codec format of the frame is user defined and set using the
"--imem-codec=<four_letter>," where 4 letter is the code for your
codec of your source data.
*/
int MyImemGetCallback (void *data,
const char *cookie,
int64_t *dts,
int64_t *pts,
unsigned *flags,
size_t * bufferSize,
void ** buffer)
{
MyImemData* imem = (MyImemData*)data;
if(imem == NULL)
return 1;
// Loop...
if(imem->mFrame >= imem->mImages.size())
{
imem->mFrame = 0;
}
// Changing this value will impact the playback
// rate on the receiving end (if they use the dts and pts values).
int64_t uS = 33333; // 30 fps
cv::Mat img = imem->mImages[imem->mFrame++];
*bufferSize = img.rows*img.cols*img.channels();
*buffer = img.data;
*dts = *pts = imem->mDts = imem->mPts = imem->mPts + uS;
return 0;
}
/**
\brief Callback method triggered by VLC to release memory allocated
during the GET callback.
To set this callback, use the "--imem-release=<memory_address>"
option, with memory_address the address of this function in memory.
\param[in] data Pointer to user-defined data, this is your data that
you set by passing the "--imem-data=<memory_address>" option when
initializing VLC instance.
\param[in] cookie A user defined string. This works the same way as
data, but for string. You set it by adding the "--imem-cookie=<your_string>"
option when you initialize VLC. Use this when multiple VLC instances are
running.
\param[int] bufferSize The size of the buffer in bytes.
\param[out] buffer Pointer to data you allocated or set during the GET
callback to handle or delete as needed.
*/
int MyImemReleaseCallback (void *data,
const char *cookie,
size_t bufferSize,
void * buffer)
{
// Since I did not allocate any new memory, I don't need
// to delete it here. However, if you did in your get method, you
// should delete/free it here.
return 0;
}
/**
\brief Method to load a series of images to use as raw image data
for the network stream.
\param[in] sourceFolder Path to folder containing jpeg or png images.
*/
std::vector<cv::Mat> GetRawImageData(const std::string& sourceFolder)
{
namespace fs = boost::filesystem;
std::vector<cv::Mat> result;
std::vector<std::string> filenames;
if(fs::exists(sourceFolder) && fs::is_directory(sourceFolder))
{
for(fs::directory_iterator dir(sourceFolder);
dir != fs::directory_iterator();
dir++)
{
std::string ext = dir->path().extension().string();
if(fs::is_regular_file(dir->status()) &&
(dir->path().extension() == ".jpeg" ||
dir->path().extension() == ".png"))
{
filenames.push_back(dir->path().string());
}
}
}
if(filenames.size() > 0)
{
// Sort from 0 to N
std::sort(filenames.begin(), filenames.end());
std::vector<std::string>::iterator filename;
for(filename = filenames.begin();
filename != filenames.end();
filename++)
{
cv::Mat img = cv::imread(*filename);
result.push_back(img);
}
}
return result;
}
int main(int argc, char* argv[])
{
// Load images first since we need to know
// the size of the image data for IMEM
MyImemData data;
data.mImages =
GetRawImageData(IMEM_SOURCE_FOLDER);
if(data.mImages.size() == 0)
{
std::cout << "No images found to render/stream.";
return 0;
}
int w, h, channels;
w = data.mImages.front().cols;
h = data.mImages.front().rows;
channels = data.mImages.front().channels();
// You must create an instance of the VLC Library
libvlc_instance_t * vlc;
// You need a player to play media
libvlc_media_player_t *mediaPlayer;
// Media object to play.
libvlc_media_t *media;
// Configure options for this instance of VLC (global settings).
// See VLC command line documentation for options.
std::vector<const char*> options;
std::vector<const char*>::iterator option;
options.push_back("--no-video-title-show");
char imemDataArg[256];
sprintf(imemDataArg, "--imem-data=%#p", &data);
options.push_back(imemDataArg);
char imemGetArg[256];
sprintf(imemGetArg, "--imem-get=%#p", MyImemGetCallback);
options.push_back(imemGetArg);
char imemReleaseArg[256];
sprintf(imemReleaseArg, "--imem-release=%#p", MyImemReleaseCallback);
options.push_back(imemReleaseArg);
options.push_back("--imem-cookie=\"IMEM\"");
// Codec of data in memory for IMEM, raw 3 channel RGB images is RV24
options.push_back("--imem-codec=RV24");
// Video data.
options.push_back("--imem-cat=2");
// If using RAW image data, like RGB24, then you
// must specify the width, height, and number of channels
// to IMEM. Other codes may have that information within
// the data buffer, but RAW will not.
char imemWidthArg[256];
sprintf(imemWidthArg, "--imem-width=%d", w);
options.push_back(imemWidthArg);
char imemHeightArg[256];
sprintf(imemHeightArg, "--imem-height=%d", h);
options.push_back(imemHeightArg);
char imemChannelsArg[256];
sprintf(imemChannelsArg, "--imem-channels=%d", channels);
options.push_back(imemChannelsArg);
//options.push_back("--verbose=2");
// Load the VLC engine
vlc = libvlc_new (int(options.size()), options.data());
// Create a media item from file
media = libvlc_media_new_location (vlc, "imem://");
// Configure any transcoding or streaming
// options for the media source.
options.clear();
// Stream as MPEG2 via RTSP
//options.push_back(":sout=#transcode{venc=ffmpeg{keyint=1,min-keyint=1,tune=zerolatency,bframes=0,vbv-bufsize=1200}, vcodec=mp2v,vb=800}:rtp{sdp=rtsp://:1234/BigDog}");
// Stream as MJPEG (Motion JPEG) to http destination. MJPEG encoder
// does not currently support RTSP
//options.push_back(":sout=#transcode{vcodec=MJPG,vb=800,scale=1,acodec=none}:duplicate{dst=std{access=http,mux=mpjpeg,noaudio,dst=:1234/BigDog.mjpg}");
// Convert to H264 and stream via RTSP
options.push_back(":sout=#transcode{vcodec=h264,venc=x264,vb=0,vbv-bufsize=1200,bframes=0,scale=0,acodec=none}:rtp{sdp=rtsp://:1234/BigDog}");
// Set media options
for(option = options.begin(); option != options.end(); option++)
{
libvlc_media_add_option(media, *option);
}
// Create a media player playing environment
mediaPlayer = libvlc_media_player_new_from_media (media);
// No need to keep the media now
libvlc_media_release (media);
// play the media_player
libvlc_media_player_play (mediaPlayer);
boost::this_thread::sleep(boost::posix_time::milliseconds(60000));
// Stop playing
libvlc_media_player_stop (mediaPlayer);
// Free the media_player
libvlc_media_player_release (mediaPlayer);
// Free vlc
libvlc_release (vlc);
return 0;
}