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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.

• FFprobe reading incorrect resolution value despite players rendering it correctly

  24 juillet 2015, par Boehmi

  I’m creating a video from a stream with the help of FFMPEG and I also use FFPROBE to gather information for use on a status page like resolution, codecs et cetera.

  When FFProbe parses my video for information, I get a resolution value of 544x576 (almost a square !), but an aspect ratio of 16:9.

  These values are consistent on both the input stream and my saved video.

  When I watch the video in the standard HTML5 Player, VLC or FFPLAY however, I get a video with the proportions of 16:9 and a resolution (measured using an image editing program) of 1024x576 that does look native and not stretched in any way.

  Even if I re-encode the video using slightly different codecs, this incorrect resolution value persists, even though every player I use displays it correctly.

  This is slightly inconvenient because I am relying on getting the correct resolution value from the video for further processing.

  I’m also using a recent FFMPEG+FFPROBE version that was compiled on the 15th of July.

  Is this a bug within FFMPEG or is there anything I’m doing wrong ?

  Used command lines :

  FFMPEG :

  ffmpeg -i source -loglevel debug -vcodec copy -acodec copy -bsf:a aac_adtstoasc -movflags +faststart -t 360 -y video.mp4

  FFPROBE (I parse the output of this directly and save the values) :

  ffprobe -i source -show_format -show_streams 

  FFProbe output :

  width=544
  
  height=576
  
  coded_width=544
  
  coded_height=576
  
  has_b_frames=2
  
  sample_aspect_ratio=32:17
  
  display_aspect_ratio=16:9

  I can see that the sample aspect ratio is different from the display aspect ratio, but how come the video looks proper in 16:9 when it’s supposedly encoded at a near square resolution ?

• dds : Fix palette decoding

  21 juillet 2015, par Vittorio Giovara

  dds : Fix palette decoding
  Red and blue channels were decoded in the wrong order.
  Found-By : ami_stuff
  

  • [DH] libavcodec/dds.c
  • [DH] tests/ref/fate/dds-pal
  • [DH] tests/ref/fate/dds-pal-ati