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• ffmpeg datascope filter : How does it works ?

  25 octobre 2022, par tony

  I'm trying to see how the datascope filter is displaying the color values for a black and white image. I was expecting to see a part of the image with 0xfff and one with 0x000 value,
instead I obtained only the 0xfff for white

  


  ffmpeg \
-f lavfi -i color=white:100x100 \
-f lavfi -i color=black:100x100 \
-lavfi '[0:v][1:v]hstack[out]' \
-map [out] \
-frames 1 \
blackAndWhite.png ; \


ffmpeg \
-i blackAndWhite.png \
-vf 'datascope' \
data.png


  


  what am I seeing ?


  


• FFMpeg - Freeze First Frame for X seconds

  13 mars 2021, par John Doe

  I need to pause/freeze the first frame of the video for 2 seconds before proceeding to the scroll effect. Here's what I have :

  


  ffmpeg -y -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=44100 -loop 1 -i "temp.jpg" -i "floating.png" -filter_complex "[1:v]fps=fps=30,crop=1280:720:0:'t*(ih-oh)/120',overlay,scale=1280x720,drawtext=fontfile='font.ttf':text='text here':x=20:y=675:fontsize=60:fontcolor=white:shadowcolor=black:shadowx=2:shadowy=2,drawtext=fontfile='font.ttf':text='more text':x=w-tw-20:y=670:fontsize=70:fontcolor=white:shadowcolor=black:shadowx=2:shadowy=2[out]" -t 10 -map "[out]" -map "0:a" -shortest -c:v h264_qsv -c:a aac -ac 2 -ar 44100 -vb 30M -r 30 "video.mp4"


  


  Any ideas ?

  


• Audio/Video drop when merging 3 FFmpeg commands which includes scale, pad, filter complex

  21 novembre 2018, par Mayank

  I am trying to scale 2 videos to h=240 resolution keeping the same aspect ration. Then I am merging the audio and video of these 2 videos to form a single mp4 file. I have 3 commands in total and the final result is good.

  However, I want to combine these 3 commands and get the same result in one single command. Can someone please help me in combing these commands ? Thanks in advance.

  First Command :

  ffmpeg -i 01_v.mp4 -vf "[0]scale=-1:240[scaled_240]; [scaled_240]pad=width=320:height=240:x=(320-in_w)/2:y=(240-in_h)/2:color=black" -preset ultrafast -y -r pal "1_v.mp4"

  Second Command :

  ffmpeg -i 02_v.mp4 -vf "[0]scale=-1:240[scaled_240]; [scaled_240]pad=width=320:height=240:x=(320-in_w)/2:y=(240-in_h)/2:color=black" -preset ultrafast -y -r pal "2_v.mp4"

  Third Command :

  ffmpeg -i 1_a.opus -i 2_a.opus -itsoffset 0.024181 -i 1_v.mp4 -itsoffset 0.113192 -i 2_v.mp4 -filter_complex "[1:a]adelay=15726.168|15726.168[a1]; [0:a][a1]amix; [3:v]trim=0:15.726168,geq=0:128:128[silence]; [3:v]fifo[3v]; [silence][3v]concat[3_v_silence]; [2:v]fifo[2v]; [2v][3_v_silence]hstack[out_v]; [out_v]pad=width=640:height=480:x=(640-in_w)/2:y=(480-in_h)/2:color=black" -crf 40 -preset ultrafast -y -r pal "out.mp4"

  I have tried to combine the above 3 commands and formed a single command. However, the result is not good with muted audio for few seconds in the middle of playback, also the 2nd video gets over few seconds earlier. Hence ending up in messing up the audio/video sync.

  This is my single command which doesn’t produce the desired result :

  ffmpeg -i 1_a.opus -i 2_a.opus -itsoffset 0.024181 -i 01_v.webm -itsoffset 0.113192 -i 02_v.webm -filter_complex "[1:a]adelay=15726.168|15726.168[a1]; [0:a][a1]amix; [3:v]trim=0:15.726168,geq=0:128:128[silence]; [3:v]fifo[3v]; [silence][3v]concat[3_v_silence]; [2:v]scale=-1:240[2v_scaled_240]; [2v_scaled_240]pad=width=320:height=240:x=(320-in_w)/2:y=(240-in_h)/2:color=black[2v_padded]; [3_v_silence]scale=-1:240[3v_scaled_240]; [3v_scaled_240]pad=width=320:height=240:x=(320-in_w)/2:y=(240-in_h)/2:color=black[3v_padded]; [2v_padded]fifo[2v]; [2v][3v_padded]hstack[out_v]; [out_v]pad=width=640:height=480:x=(640-in_w)/2:y=(480-in_h)/2:color=black" -crf 40 -preset ultrafast -y -r pal out.mp4