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• Why ffmpeg developers using "runtime if" with macrofied condition

  4 avril 2022, par Pavel Korotkevich

  I'm looking to FFmpeg source code and I find it weird to use weird code like this :

  


  #define MACRO 0
void func(void)
{
    if (MACRO) 
    {
        //code
    }
}


  


  Is there any reason to use "if" instead of "#if ... #endif" when dealing with macros ?

  


  Some examples of this in ffmpeg repo

  


  

  • GitHub - libavcodec/me_cmp.c

  


  • GitHub - libavcodec/h264pred.c

  


  • GitHub - libavcodec/h264qpel.c

  


  • GitHub - libavcodec/h264chroma.c

  


  • GitHub - libavcodec/h264dsp.c

  


  • GitHub - libavcodec/videodsp.c

  


  • GitHub - libavutil/cpu.c

  


  


• Resize to a specific width and height using ffmpeg

  15 juin 2014, par Lambda Dusk

  I need to generate thumbnails for videos, automatically. I cannot predict the format of the video, but I need the thumbnail to be 220x120 pixels, always. Using -s 220x120 produces a weird stretch, just like -vf "scale=220:120". I’d like the stretching to be uniform, either cutting away top and bottom if the video is too high or adding black borders.

• Why does my video have an audio/mp4 mime type [duplicate]

  22 février 2018, par Tucker Peebles

  This question already has an answer here :

  • How do you safely identify whether an mp4 is an audio only or video file
    
    1 answer
    
  • Using ffprobe to check audio-only files
    
    3 answers
    

  I have a video file but it has a mime type of "audio/mp4". Why would that happen. The user who sent it to me said it came from a Flip video camera and was uploaded by usb to her computer.

  In my program, I’m checking for ’video/mp4’ mime type when I’m trying to determine if it’s a video, but I want to eventually support audio uploads too which would need to check ’audio/mp4’.

  Unfortunately, the video is a personal video of the user’s child so I don’t want to upload it here. Let me know if there is any information I can provide about the video that would help.