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• Stream video content through Web API 2

  12 février 2016, par FaNIX

  I’m in the process of working out what the best way is going to be to do the following :

  I have a bunch of CCTV footage files (MP4 files, ranging from 4MB-50MB in size), which I want to make available through a web portal. My first thought was to stream the file through Web API, so I found the link below :

  http://www.strathweb.com/2013/01/asynchronously-streaming-video-with-asp-net-web-api/

  After implementing a sample project, I realised that the example was based on Web API 1, and not Web API 2.1, which is what I’m using. After doing some more research, I got the code to compile with WebAPI 2.1. I then realised that if I want to do streaming I cannot use MP4 files, there is a fair amount of technical detail behind this, so here is the thread :

  Best approach to real time http streaming to HTML5 video client

  It seems for this to work I need to encode my MP4 files to something like WebM, but that is going to take too much time. Icecast (http://icecast.org/), which is a streaming server, but I haven’t tried it out yet, again not sure if this is what I need to do.

  Now that I think of it, I actually don’t need live streaming, I just need to allow the client to play the video file through their browser, perhaps using HTML5 video element ? The thing is, my application needs to work on IOS as well, so I reckon that means I cant even encode my MP4 to FLV and just use flash.

  All I really need is to have all my video clips as thumbnails on a web page, and if the client clicks on one, it begins to play ASAP, without having to download the entire file. Think of the "Watch Trailer" feature on imdb.com. Simply just play a video file, thats really what I want. I don’t need LIVE streaming, which is what I think WebM is for ? Again, not sure.

• ffmpeg copy stream preserving FPS

  10 mars 2017, par James Taylor

  I have a stream that I know is outputting at a certain frame rate (30 FPS). I want to use ffmpeg to make a copy of this stream and save it to disk.

  I have the following command :

  ffmpeg -i http://input/ -c copy -map 0 \
  
      -f segment -strftime 1 -segment_time 900 \
  
      -segment_atclocktime 1 -segment_format mp4 %Y-%m-%d_%H-%M-%S.mp4

  But when I run the command, I see the following :

  frame=   32 fps=3.9 q=-1.0 Lsize=N/A time=00:00:01.27 bitrate=N/A

  Where it appears the FPS is hovers around 4.0 FPS and time moves slower than real time.

  I tried added -re (copy the rate of the input stream) and -r 30 (manually set the rate to 30 FPS) flag specified before the input file, but it didn’t seem to work.

  I also read a similar question here using -framerate 30, but that option doesn’t exist in the man pages and is an Invalid option.

  Any help would be greatly appreciated !

  ---

  So I let the modified command (removing the flags -c copy -map 0) run for exactly 5 minutes. Running ffprobe yields :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '2017-03-10_01-09-12.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.2.100
  
    Duration: 00:00:15.43, start: 0.066016, bitrate: 13416 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc), 1024x768, 13414 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler

  Again, this only produces 15 seconds of video and I can’t seem to get a 1:1 relationship between the input stream of 30 FPS and an output stream also in 30 FPS in real time. Playing the video yields something that’s sped up.

• Is there a way to detect if a video is of poor quality with ffmpeg ? [on hold]

  29 avril 2015, par Daniela Carrasco

  I am working on a project where I am tracking the amount of time someone spends looking at a video.

  There are some videos in the mix that lag horribly and so it makes it seem as if the person is looking for longer than they actually are because the image is frozen with their eyes still looking at it, even though in real time, they aren’t looking.

  I thought that using frames per second would help me detect this but it seems to be inconsistent. I am using VCode and FFmpeg as well as FFprobe to try and figure this out.