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• ffmpeg avformat_open_input cannot open file

  21 mai 2014, par Zyoo

  I’m trying to open an existing Mp3 file via Android NDK, but it won’t open.

  Java

  private static String FILENAME = "/mnt/sdcard/My Audios/Doomsday.mp3";

  C

  if ((res=avformat_open_input(&pFormatCtx, path, NULL, NULL)) < 0) {
  
      __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "file name: %s", path);
  
      printf("Hello %s\n", path);
  
      __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "cannot open input file");
  
      __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "%d", res);
  
      return res; // couldn't open file
  
  }

  Here’s the log

  

  Definitely sure the file exists.
  Thanks.

• Syncing decoded video using Ffmpeg

  30 juin 2012, par Infiniti Fizz

  I am using Ffmpeg to decode and play video files. I have currently got the video playing and the audio playing at as fast as the CPU can decode and display them. The problem is that I want to play the video and audio in sync using the system clock.

  I've searched around for some help but can't find anything substantial other than dranger's tutorial 05 but I don't really understand what he is doing because my program isn't written in the same way as his.

  I am using mjpeg files and so the pts seems to be retrieved every single time a frame is decoded, I have multiplied the pts by the time_base as dranger does to get the value in seconds but the resolution seems to be only seconds and so I get the value "6" 25 times and then "7" 25 times as the video runs at 25 frames per second.

  Is there not a more accurate value ? Or way to get a more accurate value and if so, how would I go about syncing to this value ? I am using SDL to display the value so can I just use a SDL_Delay() of the value I get ?

  Thanks for your time,

  Infinitifizz

• Best way to load in a video and to grab images using c++

  17 octobre 2011, par Seb

  I am looking for a fast way to load in a video file and to create images from them at certain intervals ( every second, every minute, every hour, etc.).

  I tried using DirectShow, but it just ran too slow for me to start the video file and move to a certain location to get data and to save it out to an image. Even if I disabled the reference clock. Tried OpenCV, but it has trouble opening the AVI file unless I know the exact codec information. So if I know a way to get the codec information out from OpenCV I may give it another shot. I tried to use FFMPEG, but I don't have as much control over it as well as I would wish.

  Any advice would be greatly appreciated. This is being developed on a Windows box since it has to be hosted on a Windows box.