CODEWITHSUNDEEP
videoffmpegvideo-processing
Samsy
Samsy

Reputation: 375

FFMPEG cropping size is always wrong

I need a bunch of video to be EXACTLY 1024x512 ( power of 2 video ), not a pixel less, not a pixel more..

I'm scaling them first to 1024 width

Then cropping them to 1024x512

Problem is..

result always ends up with 1 pixel more or 2 less pixels in width etc...

Source dimension : 1624 × 1080
Output dimension : 1022 × 512

Source dimension : 1264 × 720
Output dimension : 1025 × 512

rm -R ./output

mkdir output

cd input

for i in *.mp4;

  do name=`echo "$i" | cut -d'.' -f1`

  FILE="${name}"

  TMP="temp.mp4"

  INPUT="${FILE}.mp4"

  OUT_PUT="../output/${FILE}.mp4"

  JPEG_OUTPUT="../output/${FILE}.jpg"

  echo FILE

  echo INPUT

  ffmpeg -i $INPUT -filter:v scale=1024:-2 -c:a copy ${TMP}

  ffmpeg -i ${TMP} -filter:v "crop=1024:512:exact=1" -c:a copy ${OUT_PUT}

  # ffmpeg -loglevel panic -i $OUT_PUT -vframes 1 -f image2 $JPEG_OUTPUT

  rm ${TMP}

done

Upvotes: 0

Views: 847

Answers (1)

Gyan
Gyan

Reputation: 93329

Use

ffmpeg -i $INPUT -filter:v "scale=1024:-2,crop=1024:512:exact=1,setsar=1" -c:a copy ${TMP}

Due to an adjustment by the scale filter to SAR, it's likely that your media checker is reporting a resolution corrected by a non-unit SAR. The setsar filter resets SAR to 1 to prevent that.

Upvotes: 1

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