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• ffmpeg combine existing filter_complex with upscaleto e.g. 720p

  24 novembre 2019, par Tom Meyer

  Currently I am combining two videos using this filter :

  -filter_complex "[1:v][0:v]scale2ref=main_w:ih[sec][pri]; [sec]setsar=1,drawbox=c=black:t=fill[sec];[pri][sec]hstack[canvas]; [canvas][1:v]overlay=main_w-overlay_w"

  The output is the following : test.png (Green is the first video input, orange the second one) The whole video (red) has a format of 1600x540 (That might change depending on the input sizes.)

  My question is whether there is a way to upscale this video to maybe 1920x1080 or 1280x720 in the same command. By upscaling I mean to change its size and to fittingly insert black bars on the side/top.

• Normalise video aspect ratio with ffmpeg

  4 juillet 2022, par Benjamin Tamasi

  I'm parsing a video stream from an application that receives an h264 stream and writes it to a file. (The frame data is an unencrypted depacketized H.264 elementary stream).

  


  I use ffmpeg to resize it to a fixed resolution. (I overlay it on a black canvas with -f lavfi -i color=c=black:s=1920x1080:r=30) and -filter_complex [1][0]scale2ref=w='if(gt(mdar\,dar),iw,oh*mdar)':h='if(gt(mdar\,dar),ow/mdar,ih)'[2mp4][base];[base][2mp4]overlay=x='(W-w)/2':y='(H-h)/2':eof_action=pass[vout]

  


  My issue is, that since this stream is coming from a phone's camera, whenever the orientation of the phone changes, the stream's aspect ratio changes. It can go from portrait to landscape, and back, in the same stream. When I open the file in vlc, it handles it quite nicely by resizing the window of the player to match the aspect ratio as it changes.

  


  How can I "normalise" the video, so it's always nicely overlayed on my black canvas as the aspect ratio changes ? Currently it's just using the initial aspect ratio, and if that changes mid stream, it will ignore the change, effectively distorting the stream by squishing or stretching it.

  


  Is there some way I can get ffmpeg to do this ?

  


• Creating marketing videos

  7 juin 2020, par Cengiz

  I am trying to create a marketing video with multiple images (png/jpg) after adding texts on every single image and of course with their duration. Therefor, I use several ffmpeg commands, because I am not able to do it with just one command.

  



  How can I define a text and a duration for every image before adding it to the video ?

  



  My example batch file :

  



   !/bin/bash

  



  echo "[Start]"
ffmpeg \
 -i '01.jpg' \
 -vf drawtext="\text='Stack Overflow' : fontcolor=white : fontsize=24 : box=1 : boxcolor=black@0.9 : boxborderw=5 : x=(w-text_w)/2 : y=(h-text_h)/2" \
 -codec:a copy \
 -y 'out-a.mp4'
ffmpeg \
 -i '02.jpg' \
 -vf drawtext="\text='Another Text' : fontcolor=white : fontsize=24 : box=1 : boxcolor=black@0.9 : boxborderw=5 : x=(w-text_w)/2 : y=(h-text_h)/2" \
 -codec:a copy \
 -y 'out-b.mp4'
ffmpeg \
 -i '03.jpg' \
 -vf drawtext="\text='Hello World' : fontcolor=white : fontsize=24 : box=1 : boxcolor=black@0.9 : boxborderw=5 : x=(w-text_w)/2 : y=(h-text_h)/2" \
 -codec:a copy \
 -y 'out-c.mp4'
ffmpeg \
 -i out-*.mp4 \
 -vf scale=768x420 \
 -c:v libx264 \
 -r 30 \
 -pix_fmt yuv420p \
 -y 'output.mp4'
echo "[End]"

  



  Thanks to all
Cengiz