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• FFmpeg side by side video (widescreen) and play each video one by one

  6 mai 2020, par Knide

  new to ffmpeg, I've already did this to combine 3 or more videos that I have into 1 video :

  



  ffmpeg -i left.mp4 -i center.mp4 -i right.mp4 -filter_complex "[0:v:0][1:v:0][2:v:0]hstack=inputs=3" -c:v libx264 -tune film -crf 16 -b:a 256k output.mp4


  



  Now what I am having trouble with is the videos have different play times (in seconds) what I want to achieve is have them all side by side (working with the code above) then have left.mp4 play first (with it's own audio) once done, center.mp4 plays (has own audio), and when done too, right.mp4 plays (has own audio) as well and the video is over.

  



  Can someone enlighten me on how to achieve this ? Thank you !

  


• lavc/h274 : transpose IDCT

  28 septembre 2023, par Niklas Haas

  lavc/h274 : transpose IDCT
  This is mathematically equivalent to what we were doing before, but
  
  gives subtly different results due to rounding (rows first vs columns
  
  first). Doing it this way makes our film grain database generation match
  
  reference implementation and now produces bit-exact outputs in my
  
  testing.
  Rename the transposed variables to be a bit less confusing.
  

  • [DH] libavcodec/h274.c

• MP4 to DASH using ffmpeg linux too slow

  16 mai 2022, par darox

  Currently, I'm working at a project that contains 2000 video mp4 files, and I need convert all of them in mpeg dash files.

  



  I have this script :

  



  MYDIR=$(dirname $(readlink -f ${BASH_SOURCE[0]}))
SAVEDIR=$(pwd)

# Check programs
if [ -z "$(which ffmpeg)" ]; then
    echo "Error: ffmpeg is not installed"
    exit 1
fi

if [ -z "$(which MP4Box)" ]; then
    echo "Error: MP4Box is not installed"
    exit 1
fi

cd "$MYDIR"

TARGET_FILES=$(find ./ -maxdepth 1 -type f \( -name "*.mov" -or -name "*.mp4" \))
for f in $TARGET_FILES
do
  fe=$(basename "$f") # fullname of the file
  f="${fe%.*}" # name without extension

  if [ ! -d "${f}" ]; then #if directory does not exist, convert
    echo "Converting \"$f\" to multi-bitrate video in MPEG-DASH"

    mkdir "${f}"

    ffmpeg -y -i "${fe}" -c:a aac -b:a 192k -vn "${f}_audio.m4a"


    ffmpeg -y -i "${fe}" -preset slow -tune film -vsync passthrough -write_tmcd 0 -an -c:v libx264 -x264opts 'keyint=25:min-keyint=25:no-scenecut' -crf 23 -maxrate 800k -bufsize 2000k -pix_fmt yuv420p -vf "scale=-2:720" -f mp4  "${f}_800.mp4"
    # static file for ios and old browsers and mobile safari
    ffmpeg -y -i "${fe}" -preset slow -tune film -movflags +faststart -vsync passthrough -write_tmcd 0 -c:a aac -b:a 160k -c:v libx264  -crf 23 -maxrate 1400 -bufsize 3000k -pix_fmt yuv420p -f mp4 "${f}/${f}.mp4"


    rm -f ffmpeg*log*
    # if audio stream does not exist, ignore it
    if [ -e "${f}_audio.m4a" ]; then
        MP4Box -dash-strict 2000 -rap -frag-rap  -bs-switching no -profile "dashavc264:live" "${f}_5000.mp4" "${f}_3000.mp4" "${f}_1500.mp4" "${f}_800.mp4" "${f}_400.mp4" "${f}_audio.m4a" -out "${f}/${f}.mpd"
        rm "${f}_5000.mp4" "${f}_3000.mp4" "${f}_1500.mp4" "${f}_800.mp4" "${f}_400.mp4" "${f}_audio.m4a"
    else
        MP4Box -dash-strict 2000 -rap -frag-rap  -bs-switching no -profile "dashavc264:live" "${f}_5000.mp4" "${f}_3000.mp4" "${f}_1500.mp4" "${f}_800.mp4" "${f}_400.mp4" -out "${f}/${f}.mpd"
        rm "${f}_5000.mp4" "${f}_3000.mp4" "${f}_1500.mp4" "${f}_800.mp4" "${f}_400.mp4" 
    fi
    # create a jpg for poster. Use imagemagick or just save the frame directly from ffmpeg is you don't have cjpeg installed.
    ffmpeg -i "${fe}" -ss 00:00:00 -vframes 1  -qscale:v 10 -n -f image2 - | cjpeg -progressive -quality 75 -outfile "${f}"/"${f}".jpg

    fi

done

cd "$SAVEDIR"


  



  This is working fine, but, taking a long time to convert only single file, I have intel 7 and a simple mp4 file take 30 min to be converted. How can I accelerate this process ? Must I change something in this script ?

  



  Thank you.