Play video using libVLC from memory in python

Question

I am trying to use python libVLC bindings to play files after they are read into memory. I have the following code that reads a valid video file in memory. I need to play the video directly from memory now.

import vlc File1 = open('vid.webm','rb') Axel = File1.read() 

Now I need to play the contents in Axel, how can I do this.

Information on how to do this in C, Java, etc. can also help.

Edit: It is clear that I will need to use the imem module, but I cannot find any help regarding its implementation.

Answer 1

For this you need to use the imem libvlc module. This can be really confusing as it is not a publicly documented API right now. However, I followed a few other posts related to this here and on the VideoLan forums. Below is an example of the code that I worked in C ++ today that uses JPEG images loaded into memory to create a video stream. You can follow the same steps, but you just need to change the codec of your data in memory (see line 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; } 

Answer 2

I know this question is very old, but I was looking for the same thing and it might be useful.

If you are working on Linux, you can hack the system as follows: create the tmpfs partition and just copy the files to the tmpfs partition when the application starts.

Now you can download them from there.