2020-11-13

Managing Film Scans With FFmpeg

I have been trying to figure the best way to play and manage film scans and learned a bag of new tricks from reto.ch

Playing a DPX sequence

ffplay [DIRECTORY]/Scan\_%06d.tif

The regex %06d matches six digits long numbers, possibly with leading zeroes. This allows to read in ascending order, one image after the other,the full sequence inside one folder. Of course, the command must match the naming convention actually used.

Make a ProRes file from the scan sequence

ffmpeg
 -f image2 \
 -framerate 24 \
 -i [DIRECTORY]/Scan\_%06d.tif \
 -c:v prores_ks \
 -profile:v 3 \
 -filter:v "scale=1440:1080:flags=lanczos, pad=1920:1080:240:0" \
 ProRes.mov
  • -f image2 forces the image file de-muxer for single image files
  • -framerate sets the frame rate to 24

NOTE: The previous two parameters must be before the input file, because they are applied to the input file.

  • -i path, name and extension of the input file. The regex %06d matches six digits long numbers, possibly with leading zeroes. This allows to read in ascending order, one image after the other, the full sequence inside one folder. The command must of course match the naming convention actually used.
  • -c:v chooses the ProRes video codec
  • -profile:v the flavour ProRes 422 HQ has the video profile 3
  • -filter:v filters the video stream: scaling to the correct size (we use the Lanczos scaling algorithm which is slower but better than the default bilinear algorithm) and padding the 4:3 format into the 16:9 HD format with pillar box

Make a H264 file from the scan sequence

ffmpeg \
 -f image2 \
 -framerate 24 \
 -i DUFAY*TIFF/Dufay*%06d.tif \
 -c:v libx264 \
 -preset veryslow \
 -qp 18 \
 -filter:v "scale=1440:1080:flags=lanczos, pad=1920:1080:240:0" \
 -pix_fmt yuv420p \
 Scan_H264_1.mp4

Make an access file H.264 directly form the conservation files TIFF.

  • -c:v chooses the H.264 codec by using the libx264 library
  • -preset chooses the very slow preset which gives the best result
  • -qp a quantisation parameter of 18 means “visually lossless”
  • -an prevents an empty audio track ([a]udio [n]o)

Make a H264 file from the ProRes file

ffmpeg \
 -i ProRes.mov \
 -c:v libx264 \
 -preset veryslow \
 -qp 18 \
 -pix_fmt yuv420p \
 -an \
 Scan_H264_2.mp4