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Accepted
Toodarday
Asked: 2019-04-13 11:27:47 +0800 CST

ffmpeg - Watermark every x second fade in/out and adjust for video resolution

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I am using the current ffmpeg command to convert multiple videos and create a watermark that is a scrolling text that goes from right to left to right every 120 seconds of play time.

find /home/video/ -type f -execdir ffmpeg -i '{}' -filter:v "drawtext=fontfile=/root/FreeSans.ttf:text='QWERTY':[email protected]:fontsize=26:y=h-line_h-30:x=w/20*mod(t\,120),scale=854:480" -pix_fmt yuv420p -c:v libx264 -preset slow -b:v 1000k -minrate 500k -maxrate 2000k -bufsize 2000k -c:a aac -ar 44100 -b:a 128k -movflags +faststart '/home/video/new/{}.mp4' \;

I would like to modify the watermark so it looks something like this

enter image description here

I would like the text shown above to fade in every 120 seconds and last for 15 seconds. Be bold format and the same colour (black).

"qwerty qwerty qwerty qwerty" new line
"qwerty qwerty qwerty qwerty"

Another issue I currently have with the current command I am using is with different video frames. For example if the video is only 800x600 the text will be very large. If the video is 1920x1080 the text will be extremely small. I would like the text size to be adjusted depending on the frame rate. It should look like above in terms of screen size.

ffmpeg

1 Answers

  1. Best Answer

    One method is to use ASS subtitles with the subtitles filter:

     ffmpeg -i input -filter_complex "subtitles=fade.ass" -c:a copy output

    Advantages:

    • Fading and timing is controlled by the ASS file.
    • The text will be automatically resized to fit the video size.
    • Subtitles are more customizable than drawtext.
    • Text can auto wrap if needed unlike drawtext.
    • ffmpeg command is simple.

    Disadvantage:

    • Each instance is a separate line in the ASS file. Not a big deal for short videos. There might be a way to address this with an ASS or karaoke feature, but I don't know off-hand.

    Sample ASS file (created in Aegisub 3.2.2):

    [Script Info]
; Script generated by Aegisub 3.2.2
; http://www.aegisub.org/
Title: Default Aegisub file
ScriptType: v4.00+
WrapStyle: 0
ScaledBorderAndShadow: yes
YCbCr Matrix: None

[Aegisub Project Garbage]
Last Style Storage: Default
Video Position: 749

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Default,Arial,20,&H00000000,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,0,0,2,10,10,10,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:15.00,Default,,0,0,0,,{\fad(500,500)}qwerty qwerty qwerty qwerty\Nqwerty qwerty qwerty qwerty
Dialogue: 0,0:02:00.00,0:02:15.00,Default,,0,0,0,,{\fad(500,500)}qwerty qwerty qwerty qwerty\Nqwerty qwerty qwerty qwerty
Dialogue: 0,0:04:00.00,0:04:15.00,Default,,0,0,0,,{\fad(500,500)}qwerty qwerty qwerty qwerty\Nqwerty qwerty qwerty qwerty
Dialogue: 0,0:06:00.00,0:06:15.00,Default,,0,0,0,,{\fad(500,500)}qwerty qwerty qwerty qwerty\Nqwerty qwerty qwerty qwerty
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