Commands used at BAVC

Basics

# 0.  Set the desktop as working space
#
#     In order to find the generated files easier.

cd ~/Desktop

#     Generate the working files
#
# 1.  The Mandelbrot pattern is a fractal curve that allows to notice errors
#     quickly. This gives an image file.
#
#     Parameters:
#     -f        uses lafvi, FFmpeg’s virtual input device
#     -i        choses the Mandelbrot pattern as input «file»
#     -t        duration in seconds
#     -pix_fmt  choses the YUV 4:2:0 planar pixel encoding [Y’C_BC_R would be the
#               accurate writing]
#               path, name and extension of the output file [no -o is needed]

ffmpeg -f lavfi -i mandelbrot -t 10 -pix_fmt yuv420p mandelbrot.mov

# 2.  The musical note A (aka 440 Hz) gives a sound file.
#
#     Parameters:
#     -f  uses lavfi, FFmpeg’s virtual input device
#     -i  evaluates a sinus function
#     -t  duration in seconds
#         path, name and extension of the output file [no -o is needed]

ffmpeg -f lavfi -i aevalsrc="sin(440*2*PI*t)" -t 10 A.wav

# 3.  Join the generated image and the sound files
#
#     Parameters:
#     -i  path, name and extension of the first input file
#     -i  path, name and extension of the second input file
#         path, name and extension of the output file [no -o is needed]

ffmpeg -i mandelbrot.mov -i A.wav mandelaaa.mov

# 4.  Extract the technical metadata
#
#     Parameters:
#     -show_format   shows the container’s metadata
#     -show_streams  shows the codec’s metadata
#     -print_format  choses the output format

ffprobe mandelbrot.mov

ffprobe -show_format mandelbrot.mov

ffprobe -show_streams mandelbrot.mov

ffprobe -show_format -show_streams mandelbrot.mov

ffprobe -show_format -show_streams -print_format flat mandelbrot.mov

ffprobe -show_format -show_streams -print_format json mandelbrot.mov

ffprobe -show_format -show_streams -print_format xml mandelbrot.mov

#     See also: avpres.net/FFmpeg/probe_json
#
# 5.  Transform the container
#
#     Consists on demultiplex the container given as input, copy the data
#     without decoding and encoding, and multiplex into the output container.
#
#     Parameters:
#     -c  in this example we chose to copy the codec

ffmpeg -i mandelbrot.mov -c copy mandelbrot.avi

# 6.  MD5 hash values for each frame in the video stream
#
#     Parameters:
#     -f  library framemd5 is used to calculate the MD5 checksum

ffmpeg -i mandelbrot.mov -f framemd5 mandelbrot_mov_frames.md5

ffmpeg -i mandelbrot.avi -f framemd5 mandelbrot_avi_frames.md5

cat mandelbrot_mov_frames.md5

cat mandelbrot_avi_frames.md5

#     This shows that by modifying the container, as we made under 3., the video
#     streams remains identical on a bit level.

Transformations

#     NOTE: The backward slash \ escapes the newline. This way you can split
#     a command into more lines for readability.
#
# 7.  Make a mezzanine file ProRes 422 HQ from the conservation files TIFF.
#
#     Parameters:
#     -f image2   forces the image file de-muxer for single image files
#                 NOTE: this parameter must be before the input file
#     -i          path, name and extension of the first 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        we chose the ProRes codec
#     -profile:v  the video profile 3 is for HQ
#     -filter:v   we filter the video stream:
#                 - scaling to the correct size
#                   [we use the Lanczos scaling algorithm which is slower but
#                   better than the default bilinear algorithm]
#                 - padding the 4:3 format into the HD format with pillar-box

ffmpeg \
    -f image2 \
    -i DUFAYCOLOR/DUFAY_TIFF/Dufay_%06d.tif \
    -c:v prores \
    -profile:v 3 \
    -filter:v "scale=1440:1080:flags=lanczos, pad=1920:1080:240:0" \
    -an \
    Dufay_ProRes.mov


#     See also: avpres.net/FFmpeg/sq_ProRes
#
# 8.  Make an access file H.264 directly form the conservation files TIFF.
#
#     Parameters:
#     -c:v      we chose the libx264 codec
#     -preset   we chose veryslow which gives the best result
#     -qp       a quality parameter of 18 means «visually lossless»

ffmpeg \
    -f image2 \
    -i DUFAYCOLOR/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 \
    -an \
    Dufay_H264_1.mp4

#     See also: avpres.net/FFmpeg/sq_H264
#
# 9.  Make an access file H.264 from the mezzanine file ProRes 422 HQ.

ffmpeg \
    -i Dufay_ProRes.mov \
    -c:v libx264 \
    -preset veryslow \
    -qp 18 \
    -pix_fmt yuv420p \
    -an \
    Dufay_H264_2.mp4

#     See also: avpres.net/FFmpeg/im_H264

Advanced

# 10. Difference file

ffmpeg \
    -i Dufay_H264_1.mp4 \
    -i Dufay_H264_2.mp4 \
    -filter_complex \
        "[1]format=yuva444p, \
            lut=c3=128, \
            negate[1_with_alpha_channel]; \
        [0][1_with_alpha_channel]overlay" \
    Dufay_H264_delta.mp4

#     See also: avpres.net/FFmpeg/delta
#
# 11. Split screen

ffmpeg \
    -i Dufay_H264_1.mp4 \
    -i Dufay_H264_2.mp4 \
    -filter_complex \
        "[0]crop=iw/2:ih:0:0, \
            pad=iw*2:ih*1[left]; \
        [1]crop=iw/2:ih:iw/2:0[right]; \
        [left][right]overlay=w" \
    Dufay_H264_split.mp4
#
#     See also: avpres.net/FFmpeg/split

Exercises

horizontal split screen
split screen with a tiny black line between the two sectors

2016-07-05