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• FFMPEG inside a C#/C++ multithreaded application [on hold]

  24 décembre 2013, par oferbar

  I've inherited an application written mostly in C# that calls FFMPEG libraries to decode video frames, specifically avcodec_decode_video2().

  The general flow of a frame is like this :

  1. A frame is allocated and filled inside a C# dedicated thread (a.k.a. 'player').
  2. A managed C++ object is called to decode the frame.
  3. The Decode() method is initializing the parameters for avcodec_decode_video2() and calling this function.

  When I have 1-6 thread running in parallel and decoding frames I get no errors.
  However, when I increase the number of threads (>6) the decoding function starts failing and the got_picture_ptr parameter is returned as zero (no picture was decoded).

  The FFMPEG log gave me a hint : "no picture ooo" = out of order frames.

  I suspect that something fishy is going on with passing a managed memory block inside a frame to an the unmanaged code, maybe the pointer is moved ?

  Anyway, any advice on where to look would be greatly appreciated. I've done quite a lot of digging into this, but so far without luck.

  [Windows 7/64-bit, .NET 4.0.]

  Thx !

  Ofer

• mjpeg : Move code out of else branch

  29 juin 2013, par Luca Barbato

  mjpeg : Move code out of else branch
  Simplify the control flow and spare some vertical space.
  

  • [DBH] libavcodec/mjpegdec.c

• How to merge .ts files from a DLINK security camera losslessly ?

  13 juin 2022, par anjchang

  I have >1000s of small .ts files from a DLINK camera of a theft that occured. I first tried to merge the ts files into bigger files so that I could look for the audio where the relevant event occurred. Then in Premiere I looked for the highest sustained audio peaks (it was someone using a saw to cut out a catalytic converter). Then, I isolated the relevant 200 files where things happened on the timeline. But now, I want to export the 20 minutes of the incident with the least compression (or no compression). Apparently Adobe Premiere can export the whole timeline containing these clips, but will compress them. I have not edited any of the files, so I don't want any rendering. I just want them strung together in a "well-known" format so I can send the files to the insurance company and authorities.

  


  I used an answer from here but there were audio gaps. Some of the files had no audio, causing the problem when I first merged the files with :

  


   for i in `\ls *.ts | sort -V`; do echo "file '$i'"; done >> mylist.txt;ffmpeg -f concat -i mylist.txt -c copy -bsf:a aac_adtstoasc video.mp4