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• FFMPEG in Android not rendering Arabic characters

  14 octobre 2024, par Henry Smith

  I have an Android app that uses FFMPEG to add text overlays onto a mp4 video files.

  


  It works fine with a Latin alphabet, but when I try and add Arabic characters as an overlay on the .mp4 file, the output video displays rectangles (assuming unrecognised characters).

  


  FFMPEG command example is :
-y -i video-in.mp4 -preset ultrafast -vf "[in]drawtext=text='نقطة البداية قلا':enable='between(t, 0,5)':fontcolor=White:fontsize=20:box=1:boxcolor=black@0.5:boxborderw=5:x=(w-text_w)/2:y=(h-text_h)/2,drawtext=text='وصلات مزاحجة كبيرة الإزاحة (من ١٢ إلى ٤)':enable='between(t, 15,20)':fontcolor=White:fontsize=20:box=1:boxcolor=black@0.5:boxborderw=5:x=(w-text_w)/2:y=(h-text_h)/2[out]" -r 24 "video-out.mp4"

  


  Output mp4 video comes out a below :
enter image description here

  


  Using Android SDK Version 13, FFMPEG plugin : com.arthenica:mobile-ffmpeg-full-gpl:4.4

  


  Class example code :

  


  import com.arthenica.mobileffmpeg.ExecuteCallback
import com.arthenica.mobileffmpeg.FFmpeg

class VideoUtils() {

    fun addTextOverlay(inputFile: String, outputFile: String, text: String) {
        // create video filter for overlay text between 0 - 5 seconds, centre aligned, white font and black box
        val tempTextString =
            "drawtext=text='$text:enable='between(t, 0,5)':fontcolor=White:fontsize=20:box=1:boxcolor=black@0.5:boxborderw=5:x=(w-text_w)/2:y=(h-text_h)/2"

        // create FFMPEG command
        val cmd =
            "-y -i $inputFile -preset ultrafast -vf \"[in]$tempTextString[out]\" -r 24 \"$outputFile\""

        FFmpeg.execute(cmd)
    }
}


  


• Enhance the contrast of only a portion of an image using FFmpeg ?

  27 septembre 2021, par isend

  I am able to enhance the contrast of a whole image with the following command using FFmpeg eq filter :

  


  ffmpeg -i input.png -vf eq=contrast=2 -c:a copy output.png


  


  But can I enhance the contrast of only a portion (say, the second quadrant) of the image using FFmpeg ? I checked another post regarding how to apply a filter only on a certain duration of a film. Can I somehow insert something like enable='between(x,0,10)*between(y,0,10)' into the code above for my purpose ? Thanks.

  


• Using FFMPEG to add pillar bars

  10 février 2021, par Ewok BBQ

  I have transferred some film to video files from 16mm (native 4:3). The image looks great.

  


  When I scanned them, I scanned to a native 16:9. As I overscanned them, I got the entire height of the frame, which is what I want. But it also got the soundtrack and perforation. But I want to go just to the frame line on the sides as well.

  


  I can CROP the image down with FFMPEG to remove the information outside of the framing I want [-vf crop=1330:1080:00:00].
I know this will result in a non-standard aspect ratio.
This plays fine on a computer (vlc just adapts to the non-standard).

  


  But for standardized delivery, I would love to keep the native 1920x1080 pixels, but just make everything outside of the centered 1330:1080 black.

  


  Is there a way to specifically select where the pillar bars are ?

  


  I really want to re-encode the video as little as possible.

  


  In that vein, does anyone have a better tool than -vf crop as well ?

  


  thank you very very much.