FAQ Database Discussion Community


Video encoding pipeline - threads design

multithreading,encoding,streaming,video-capture,video-processing
I work on a system which does video capture & encoding of multiple channels. each stage takes time. The capture/encoding is done in HW, but still can take its time to finish. capture frames->encode->file-save (or stream to network) I have a dillema what would be a better approach/design: one thread...

ffmpeg recording h264 live stream got error

c,video,ffmpeg,video-streaming,video-capture
I am trying to record a h.264 live stream using the following code: AVOutputFormat* fmt = av_guess_format(NULL, "test.mpeg", NULL); AVFormatContext* oc = avformat_alloc_context(); oc->oformat = fmt; avio_open2(&oc->pb, "test.mpeg", AVIO_FLAG_WRITE, NULL, NULL); AVStream* stream = NULL; ... while(!done) { // Read a frame if(av_read_frame(inputStreamFormatCtx, &packet)<0) return false; if(packet.stream_index==correct_index) { //////////////////////////////////////////////////////////////////////// //...

What is the purpose of the LowLag* advanced features in the MediaCapture class?

windows-runtime,media,video-capture,image-capture
I don't see a real difference between the LowLag* features (controlled by LowLagPhotoCapture, LowLagPhotoSequenceCapture and LowLagMediaRecording classes) and the more classic CapturePhoto* and StartRecord*/StopRecord* methods of the MediaCapture class. What are their purpose ? What advantages have they over the classic methods ?...

CVPixelBufferUnlockBaseAddress - Block UI

ios,xcode,video-capture,avcaptureoutput
i'm struggling to debug a weird problem. In a captureOutput:didOutputSampleBuffer:fromConnection: right after CVPixelBufferUnlockBaseAddress(imageBuffer,0); the entire UI stops responding to touches. The camera preview works but all my buttons stop responding and i even added a UITapGesture and also would not work. I tried putting it into a dispatch but still...

Blackmagic DirectShow Framerate - Why am I not getting all of the video modes that my capture device is capable of?

c++,visual-studio,video,directshow,video-capture
I recently started experimenting with the DirectShow Examples of the BlackMagic SDK. I made my first application but I experienced some strange behaviour when reading the available Video modes of the Card (a DeckLink Studio 4K). Sidenote: same behaviour happens on Windows 7 Prof. & HP x64 and Win 8.1...

ALSA buffer xrun induced by low quality source in ffmpeg capture

ffmpeg,video-capture,alsa,aac,vorbis
I am attempting to transfer some old Video 8 tapes to my computer, though an EasyCap USB stick and the motherboard's sound line-in, on Ubuntu. I believe the arguments are correctly laid out below to capture from two independent streams, and encode them both into the output MP4 file. Edit:...

MediaFoundation with multi-input device?

video-capture,ms-media-foundation
I have a project where the source device has an SVideo and a Composite connector available for capture. In DirectShow, I can use IAMCrossbar to set which one to capture from, but in MediaFoundation I only get a single video stream and a C00D3704 status when I try to start...

RecordRTC video upload AmazonS3 Timeout error

javascript,amazon-s3,html5-video,webrtc,video-capture
I am currently developing a component that allows you to make webcam videos and upload them directly to amazon s3. For that purpose I user RecordRTC library and Amazon S3 storage. I have discovered a strange issue, and I am not sure whether it has to do with RecordRTC blobs...

html5 mobile capture camera and generate a preview box

javascript,html5,camera,video-capture,mobile-browser
How can I capture the camera and start a 'live preview' on a little div on the on the page on mobile? In the past I encountered some javascript web audio api that can allow you to create sound, manipulate them, start recording audio, buffer etc.. So I hope there...

Video recording doesn't stop even after max duration for it finishes in android xamarin

c#,android,xamarin,video-capture
I want to enable users to record a video for duration up to a max of 2 minutes in my app. I do provide the max duration for the video recording intent in my code but the recorder doesn't stop after that time. What do i need to do for...

CGImageRef faster way to access pixel data?

objective-c,video-capture,video-processing,cgimageref
My current method is: CGDataProviderRef provider = CGImageGetDataProvider(imageRef); imageData.rawData = CGDataProviderCopyData(provider); imageData.imageData = (UInt8 *) CFDataGetBytePtr(imageData.rawData); I only get about 30 frames per second. I know part of the performance hit is copying the data, it'd be nice if I could just have access to the stream of bytes and...

Windows Runtime API: MediaCapture how to limit recording file size

c#,windows,video-capture
With Windows.Media.Capture.MediaCapture, can we specify a size limit so that this event(RecordLimitationExceededEventHandler) is fired and recording is stopped? If not, what is the proper way to monitor file size. Thanks!...

How to show capture video in Phonegap?

jquery,cordova,phonegap-plugins,video-capture
i am using phoengap capture video plugin i have used this code <!DOCTYPE html> <html> <head> <title>Capture Video</title> <script type="text/javascript" charset="utf-8" src="cordova.js"> </script> <script type="text/javascript" charset="utf-8" src="json2.js"></script> <script type="text/javascript" charset="utf-8"> // Called when capture operation is finished // function captureSuccess(mediaFiles) { var i, len; for (i = 0, len =...

How to save recorded video on iPhone using Cordova + Phonegap?

angularjs,cordova,phonegap-plugins,ionic-framework,video-capture
I use this function to record video using Cordova + Phonegap : $scope.captureVideo = function() { var options = { limit: 1, duration: 5, saveToPhotoAlbum: true }; $cordovaCapture.captureVideo(options).then(function(videoData) { var i, path, len; for (i = 0, len = videoData.length; i < len; i += 1) { path = videoData[i].fullPath;...

video storing and synchronous streaming software (can Hadoop do it?)

hadoop,video-streaming,bigdata,video-capture,video-processing
I need some software solution for video storing. I will have a few IP cameras which has to stream into disks. This so called database records those streams.On demand I should be able to stream any of these videos or or few of them. Just do not want to merge...

Forcably Terminating DirectShow

webcam,directshow,video-capture,directshow.net
I have an application that captures video and images from webcams. Normally it works well and reliably using the DirectShow.net wrapper.Stopping the graph often leads to deadlocks however. It uses a number of filters including the sampleGrabber filter and vendor supplied filters (which we cannot edit or replace). Normal mediaControl...

Changing Max Duration of Video while Recording iOS

ios,avfoundation,video-capture,avcapturesession
I am initially starting recording with a specified Maximum Time Threshold. AVCaptureMovieFileOutput* output; //initialisations, other configurations... //Here i am setting up my MaxDuration before starting recording. [output setMaxRecordedDuration:CMTimeMakeWithSeconds(MY_MAX_LENGTH, 600)]; //Starting recording here [output startRecordingToOutputFileURL:MY_FILE_URL recordingDelegate:self]; I need to change the Maximum Recording Time Threshold while recording is going on. What...

How to detect if two successive video frames are identical or not?

c++,computer-vision,video-capture
I'm working on a computer vision project on a video. I want to detect if any two successive frames are identical or not. This is my code. capture >> currentFrame; previousFrame = currentFrame; do{ capture >> currentFrame; cvtColor( currentFrame, g1, CV_BGR2GRAY ); cvtColor( previousFrame, g2, CV_BGR2GRAY ); cv::absdiff(g1,g2,diff); int eq...