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howto:convert-images [2024/02/26 17:44] – [downscale video to 720p mkv] Wuffhowto:convert-images [2025/05/20 11:23] (current) – [lossy conversion of png to jpg] Wuff
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 </code> </code>
  
-===== lossless changing container from webm to mkv =====+===== lossy conversion of png to jpg ===== 
 +Converts all png files in the directory recursively to jpg 
 +<code> 
 +find . -iname '*.png' | while read i; do mogrify -format jpg "$i" && rm "$i"; echo "Converted $i to ${i%.*}.jpg"; done 
 +</code>
  
-Webm is a container similar to mkv and can contain various encoded video or audio streams. To change the container from webm to mkv, the following command can be used:+===== png to ico ===== 
 +To create favicon ico files, the following command creates multiple sizes and stores them in the ico file and keeps transparency. Adjust as required.: 
 +<code> 
 +convert logo.png -define icon:auto-resize=256,64,48,32,16 favicon.ico 
 +</code> 
 + 
 +===== lossless changing containers between webm/mov/mp4/mkv/m4v ===== 
 + 
 +webm/mov/mkv/mp4/m4v are container formats and can contain various encoded video or audio streams. To change the container between each other, the following command can be used, provided the used codecs inside the containers are compatible:
 <code> <code>
 ffmpeg -i file.webm -c:a copy -c:v copy file.mkv ffmpeg -i file.webm -c:a copy -c:v copy file.mkv
  
 #recursively changing containers: #recursively changing containers:
-find . -name '*.webm' -type f -exec bash -c 'ffmpeg -i "$0" -c:a copy -c:v copy "${0%.webm}.mkv"' {} \; +find . -iname '*.webm' -type f -exec bash -c 'ffmpeg -i "$0" -c:a copy -c:v copy "${0%.*}.mkv"' {} \; 
-#find . -type f -name '*.webm' -delete+#find . -type f -iname '*.webm' -delete 
 + 
 +#lossless change container mkv, webm, mov, m4v -> mp4 
 +find . -type f \( -iname "*.mkv" -o -iname "*.webm" -o -iname "*.mov" -o -iname "*.m4v" \) | while read f; do 
 +    ffmpeg -i "$f" -codec copy "${f%.*}.mp4" 
 +done
 </code> </code>
  
-===== change container mkv <-> mp4 ===== +===== high quality conversion to mp4 =====
- +
-To only change the container use the following example command - provided the codecs are compatible with mp4. The quality and size stays the same:+
 <code> <code>
-ffmpeg -i input.mkv -codec copy output.mp4+#High quality non-mp4 to mp4 conversion 
 +find . -type f \( -iname "*.mpg" -o -iname "*.asf" -o -iname "*.wmv" -o -iname "*.mpg" -o -iname "*.mpeg" -o -iname "*.avi" -o -iname "*.divx" -o -iname "*.rmvb" -o -iname "*.rm" -o -iname "*.m4v" -o -iname "*.flv" \) | while read f; do 
 +    ffmpeg -nostdin -i "$f" -vcodec libx264 -acodec aac "${f%.*}.mp4" 
 +done
 </code> </code>
 +===== find all non-mp4 files =====
 +<code>
 +#Find non-mp4 files
 +find . -type f -not \( -iname "*.mp4" \)
 +</code>
 +
 +
 +
 +
  
 ===== downscale video to 720p mkv ===== ===== downscale video to 720p mkv =====
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     if [ -f "$input" ]; then     if [ -f "$input" ]; then
         echo "Processing file: $input"         echo "Processing file: $input"
-        output="${input%.*}.convertednew.$container"+        output="${input%.*}.convertednew"
         # Check if mp4 container is desired and if subtitle is ASS format, then convert to srt, otherwise just copy subs         # Check if mp4 container is desired and if subtitle is ASS format, then convert to srt, otherwise just copy subs
         subtitles_present=$(ffprobe -v error -select_streams s -show_entries stream=codec_name -of csv=p=0:s=x "$input")         subtitles_present=$(ffprobe -v error -select_streams s -show_entries stream=codec_name -of csv=p=0:s=x "$input")
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         else         else
             subtitle_option="-scodec copy"             subtitle_option="-scodec copy"
 +        fi
 +        #check framerate to only ever reduce it and not increase it
 +        # ffprobe returns 25/1 or 24000/1001. result needs to be calculated and needs to be an integer, thus the bash $(( )).
 +        fps=$(ffprobe -v 0 -of csv=p=0 -select_streams v -show_entries stream=avg_frame_rate "$input" | sed 's#/# / #g')
 +        if [ "$fps" == "0 / 0" ]; then
 +            # some video files return 0 / 0 for avg_frame_rate, using r_frame_rate instead
 +            fps=$(ffprobe -v 0 -of csv=p=0 -select_streams v -show_entries stream=r_frame_rate "$input" | sed 's#/# / #g')
 +        fi
 +        fps=$(( $fps ))
 +        if [ $fps -gt 30 ]; then
 +            fps_option="-r 30"
 +        else
 +            fps_option=""
         fi         fi
         #-c:a copy   #copies audio as is, but mp4 works best with aac and wma cannot be in mp4 files         #-c:a copy   #copies audio as is, but mp4 works best with aac and wma cannot be in mp4 files
         #$binary -i "$input" -vf scale=-2:$resolution -c:v libx264 -r 30 -crf 28 -c:a aac -scodec copy -b:v $bitrate -maxrate $bitrate -bufsize $bufsize "$output"         #$binary -i "$input" -vf scale=-2:$resolution -c:v libx264 -r 30 -crf 28 -c:a aac -scodec copy -b:v $bitrate -maxrate $bitrate -bufsize $bufsize "$output"
         # using complex filter to prevent upscaling and only ever downscale         # using complex filter to prevent upscaling and only ever downscale
-        cmd=$binary' -i "'"$input"'" -filter_complex "scale=ceil(iw*min(1\,min('$maxwidth'/iw\,'$maxheight'/ih))/2)*2:-2" -c:v libx264 -r 30 -crf 28 -c:a aac '$subtitle_option' -b:v '$bitrate' -maxrate '$bitrate' -bufsize '$bufsize' "'"$output"'"' +        cmd=$binary' -i "'"$input"'" -filter_complex "scale=ceil(iw*min(1\,min('$maxwidth'/iw\,'$maxheight'/ih))/2)*2:-2" -c:v libx264 '$fps_option' -crf 28 -c:a aac '$subtitle_option' -b:v '$bitrate' -maxrate '$bitrate' -bufsize '$bufsize' -f '$container' "'"$output"'"' 
-        eval $cmd+        $binary -i "$input" -filter_complex "scale=ceil(iw*min(1\,min($maxwidth/iw\,$maxheight/ih))/2)*2:-2" -c:v libx264 $fps_option -crf 28 -c:a aac $subtitle_option -b:v $bitrate -maxrate $bitrate -bufsize $bufsize -f $container "$output"
         if [ $? -eq 0 ];         if [ $? -eq 0 ];
         then         then
             actualheight=$(ffprobe -v error -select_streams v -show_entries stream=height -of csv=p=0:s=x "$output")             actualheight=$(ffprobe -v error -select_streams v -show_entries stream=height -of csv=p=0:s=x "$output")
             #output2="${output%.*}."$actualheight"p.$container"             #output2="${output%.*}."$actualheight"p.$container"
-            output2="${output//.convertednew./.$actualheight""p.}"+            output2="${output//.convertednew/.$actualheight""p.}$container"
             mv "$output" "$output2"             mv "$output" "$output2"
             echo "Output file: $output2"             echo "Output file: $output2"
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     fi     fi
 done done
 +
 +# When using in Nemo, it's helpful to force a key to be pressed before closing the terminal to see the status or any errors. Uncomment the following line:
 +
 +#echo;read -rsn1 -p "Press any key to continue . . .";echo
 </code> </code>
  
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 Name=Video Downscale to max 720p Name=Video Downscale to max 720p
 Comment=Video Downscale to max 720p Comment=Video Downscale to max 720p
-Exec=<video_downscale.sh %F;echo;read -rsn1 -p "Press any key to continue . . .";echo>+Exec=video_downscale.sh %F
 Icon-Name=stock_down Icon-Name=stock_down
 Selection=notnone Selection=notnone
-Extensions=mp4;wma;avi;mkv +Extensions=mp4;wmv;avi;mkv;mov;webm;mpg 
-#Quote=double+Quote=double
 EscapeSpaces=true EscapeSpaces=true
 Terminal=true Terminal=true
 +</code>
 +
 +When using in Nemo, it's helpful to add the following to the very end of the video_downscale.sh script to force a key to be pressed before closing the terminal to see the status or any errors:
 +<code>
 +echo;read -rsn1 -p "Press any key to continue . . .";echo
 +</code>
 +
 +===== Reencode videos with high bitrate =====
 +
 +<code bash processfiles.sh>
 +#!/bin/bash
 +MYFILES=$(find /media/videofiles -type f -iname "*.mp4")
 +SAVEIFS=$IFS
 +
 +IFS=$(echo -en "\n\b")
 +for FILE in ${MYFILES}
 +do
 +  bitrate=$(ffprobe -v quiet - select_streams v:0 -show_entries stream=bit_rate -of default=noprint_wrappers=1:nokey=1 $FILE)
 +  if ! [[ $bitrate =~ ^[0-9]+$ ]];
 +  then
 +      continue
 +  fi
 +  if [ $bitrate -gt 8000000 ]
 +  then
 +      echo $bitrate" | "$FILE
 +      video_downscale.sh "$FILE"
 +  fi
 +done
 +IFS=$SAVEIFS
 +</code>
 +
 +
 +===== 3D VR SBS to 2D =====
 +
 +https://blog.interstellar.co.jp/en/2022/06/21/converting-vr180-videos-to-2d-videos-with-ffmpeg/
 +
 +<code>
 +ffmpeg -i input.mp4 -vf v360=input=equirect:output=flat:ih_fov=180:iv_fov=180:h_fov=93:v_fov=121:in_stereo=sbs:w=960:h=640 -codec:v h264 output.mp4
 +</code>
 +
 +https://video.stackexchange.com/questions/21084/how-to-convert-a-3d-movie-to-2d-using-ffmpeg
 +
 +<code>
 +ffmpeg -i input.mkv -vf stereo3d=sbsl:ml -metadata:s:v:0 stereo_mode="mono" output.mkv
 +</code>
 +Use sbsl2:ml or  -aspect 16:9 if the aspect ratio is wrong
 +
 +
 +https://stackoverflow.com/questions/66960003/unwarping-180-vr-footage-with-ffmpeg-v360-filter
 +
 +
 +https://github.com/paulpaul999/vr-video-notes/blob/main/vr-to-flat/README.md
 +<code>
 +ffmpeg -i equirectangular.mp4 -filter:v "v360=input=hequirect:output=flat:in_stereo=sbs:out_stereo=2d:d_fov=125:w=1920:h=1080:pitch=+5" -map 0 -c copy -c:v h264 -pix_fmt yuv420p flat.mp4
 +</code>
 +
 +===== Mono to Stereo MP3 =====
 +
 +Conversion using ffmpeg -ac 2 reduces volume by 3db, apparently to keep perceived loudness the same. To maintain the same volume use pan as below. 
 +
 +<code>
 +for i in {01..33}; do 
 +  ffmpeg -i "Chapter "$i".mp3" -af "pan=stereo|c0=c0|c1=c0" "Chapter "$i"s.mp3"; 
 +done
 </code> </code>
  
howto/convert-images.1708969482.txt.gz · Last modified: by Wuff