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• c# what is the best way to record live frames as Video

  13 février 2015, par Balu

  I have been checking around to convert live frames into video. And I found (NReco.VideoConverter) ffmpeg lib to convert live frames to Video, but the problem is it is taking time to write each frame to ConvertLiveMediaTask (async live media task conversion).

  I have an event that provides (raw) frames (1920x1080) (25fps) from IpCamera. Whenever I get frame I am doing the following

  //Image availbale event fired
  
  //...
  
  
  
  //...
  
  // Record video is true
  
  if(record)
  
  {
  
  //////////////############# Time taking part ##############//////////////////////
  
  var bd = frameBmp.LockBits(new Rectangle(0, 0, frameBmp.Width, frameBmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);                        
  
    var buf = new byte[bd.Stride * frameBmp.Height];                       
  
    Marshal.Copy(bd.Scan0, buf, 0, buf.Length);
  
    // write to ConvertLiveMediaTask
  
    convertLiveMediaTask.Write(buf, 0, buf.Length); // ffMpegTask
  
    frameBmp.UnlockBits(bd);
  
  //////////////////////////////////////////////////////////////////////////////////
  
  }

  As the above part is taking much time, I am loosing the frames.

  //Stop recording
  
  convertLiveMediaTask.Stop(); //ffMpegTask

  Stop recording, for this part I have used BackgroundWorker, because this takes too smuch time to save the media to file.
  My question is how can I write the frame to ConvertLiveMediaTask in faster way ? are there any possibilites to write it in background ?
  Please give me suggestions.

• How to convert a video and audio file to be smoothly played via Media Source Extension API ?

  4 octobre 2018, par Aman

  I have built a web video player using the Media Source Extension API. I have been testing my video player using local video and audio files on my PC. Everything works perfectly expect the video keeps buffering. I’m playing a 4k 60fps video, which I downloaded from YouTube. My PC is not 4k resolution, but the video smoothly plays through YouTube and VLC Media Player. I’m just surprised to why my Media Source Extension Video Player buffers even through the video and audio file are not being retrieved via network. I’m assuming that the video and audio files I’m using are causing this problem. So I will explain how I created my video and audio files first :

  1. I downloaded the video from https://www.youtube.com/watch?v=KaCQ8SQ6ZHQ&t=3s using the 4K Video Downloader https://www.4kdownload.com/products/product-videodownloader.

  2. Convert the mkv (the 4K Video Downloader only allows the 4k 60fps video to be downloaded in mkv format, for me) file to mp4 using ffmpeg in CMD : ffmpeg -i test.mkv -codec copy test.mp4.

  3. Converting the test.mp4 file to my preferred 4K resolution 3840x2160 from 3840x1632 using ffmpeg in CMD : ffmpeg -i test.mp4 -s 3840x2160 -c:a copy test_changed.mp4. (NOT SO IMPORTANT)

  4. Separating the video and audio of test_changed.mp4 to video.mp4 for video and audio.mp4 for audio using MP4Box in CMD : Video - MP4Box -single 1 test_changed.mp4 -out video.mp4 and Audio - MP4Box -single 2 test_changed.mp4 -out audio.mp4.

  5. Splitting both video.mp4 and audio.mp4 into 30 split parts each containing 5 seconds of the video and audio file. So I end up having (video_1.mp4,audio_1.mp4), (video_2.mp4,audio_2.mp4), (video_3.mp4,audio_3.mp4), ..... (video_29.mp4,audio_29.mp4), (video_30.mp4,audio_30.mp4). Using ffmpeg and one by one specifying the time range for each part in CMD :

     [For Part 1 : ffmpeg -ss 00:00:00 -to 00:00:05 -i video.mp4 video_1.mp4, ffmpeg -ss 00:00:00 -to 00:00:05 -i audio.mp4 audio_1.mp4],

     [For Part 2 : ffmpeg -ss 00:00:05 -to 00:00:10 -i video.mp4 video_2.mp4, ffmpeg -ss 00:00:05 -to 00:00:10 -i audio.mp4 audio_2.mp4],

     [For Part 3 : ffmpeg -ss 00:00:10 -to 00:00:15 -i video.mp4 video_3.mp4, ffmpeg -ss 00:00:10 -to 00:00:15 -i audio.mp4 audio_3.mp4],

     .....

     [For Part 29 : ffmpeg -ss 00:02:20 -to 00:02:25 -i video.mp4 video_29.mp4, ffmpeg -ss 00:02:20 -to 00:02:25 -i audio.mp4 audio_29.mp4],

     [For Part 30 : ffmpeg -ss 00:02:25 -to 00:02:30 -i video.mp4 video_30.mp4, ffmpeg -ss 00:02:25 -to 00:02:30 -i audio.mp4 audio_30.mp4].

  6. Fragmenting each of the video and audio parts using MP4Box in CMD(As far as I know, fragmented mp4 files are only files played via Media Source Extension API) :

     [For Part 1 : MP4Box -dash 1000 -rap -frag-rap video_1.mp4, MP4Box -dash 1000 -rap -frag-rap audio_1.mp4],

     [For Part 2 : MP4Box -dash 1000 -rap -frag-rap video_2.mp4, MP4Box -dash 1000 -rap -frag-rap audio_2.mp4],

     [For Part 3 : MP4Box -dash 1000 -rap -frag-rap video_3.mp4, MP4Box -dash 1000 -rap -frag-rap audio_3.mp4],

     .....

     [For Part 29 : MP4Box -dash 1000 -rap -frag-rap video_29.mp4, MP4Box -dash 1000 -rap -frag-rap audio_29.mp4],

     [For Part 30 : MP4Box -dash 1000 -rap -frag-rap video_30.mp4, MP4Box -dash 1000 -rap -frag-rap audio_30.mp4].

  7. I receive a fragmented file for each file with "_dashinit" being in it e.g. For Part 1 : video_1_dashinit.mp4 and audio_1_dashinit.mp4. These are the files I’m playing through Media Source Extension API.

  So I’m appending these files into my sourceBuffers and playing it with the video. I have given the test.zip file here (https://drive.google.com/file/d/1tyPBTxgpS601Xs5VEWznYhWw9PwhMHsB/view?usp=sharing) containing the test sample.

  I’m using this command in CMD to run Chrome and test my file : chrome.exe --allow-file-access-from-files

  Anyone can use this test sample and see if the video is buffering for them too. Please comment about anything I’m doing wrong, or help me construct a better 5 seconds video and audio files for MSE playable. Thanks

• avfilter/drawtext : present 'hms' formatted 'pts' in 24h format

  7 mai 2018, par Vishwanath Dixit

  avfilter/drawtext : present 'hms' formatted 'pts' in 24h format
  HMS is formatted as HH:MM:SS.mmm, but, HH part is not limited to
  
  24 hours. For example, the the drawn text may look like this :
  
  243029:20:30.342. To present the timestamp in more readable and
  
  user friendly format, this patch provides an additional option
  
  to limit the hour part in the range 0-23.
  Note : Actually the above required format can be obtained with
  
  format options 'localtime' and 'gmtime', but,  milliseconds part
  
  is not supported in those formats.
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/vf_drawtext.c