Image sequence into Matroska/FFV1

Problem

Transcode an image sequence into an FFV1 file wrapped in a Matroska container.

Solution

ffmpeg                        \
-f image2                     \
-framerate 24                 \
-i input_file_%06d.extension  \
-c:v ffv1                     \
-level 3                      \
-threads 8                    \
-coder 1                      \
-context 1                    \
-g 1                          \
-slices 24                    \
-slicecrc 1                   \
-c:a copy                     \
output_file.mkv

General command

ffmpeg                         \
-f image2                      \
-framerate frames_per_second   \
-i input_file_regex.extension  \
-c:v ffv1                      \
-level 3                       \
-threads nb_threads            \
-coder 1                       \
-context 1                     \
-g 1                           \
-slices nb_slices              \
-slicecrc 1                    \
-c:a copy                      \
output_file

Command syntax

ffmpeg

starts the command

-f image2

forces the image file de-muxer for single image files

-framerate frames_per_second

sets the frame rate

-i input_file_regex.extension

path, name with regex and extension of the input files

-c:v ffv1

The video codec FFV1 is selected.

-level 3

The version 3 of FFV1 is selected.

-threads nb_threads

This positive integer gives the number of threads to use while processing. Adjust this to match how many of the available CPU and/or GPU cores you want to use.

-coder 1

The Range coder is selected.

-context 1

The large context is selected.

-g 1

The GOP-size 1 is selected for archival use.

-slices nb_slices

Valid values include 4, 6, 9, 12, 16, 24 and 30.¹ Each frame is split into this number of slices. This affects multithreating performance, as well as filesize: increasing the number of slices may speed up performance, but also increases the filesize.

-slicecrc switch

0 = off, 1 = on. Enabling this option adds CRC information to each slice. This makes it possible for a decoder to detect errors in the bitstream, rather than blindly decoding a broken slice.

-c:a copy

re-encodes the audio stream using the same audio codec

output_file

path, name and extension of the output file

Discussion

The parameters witch apply to the input files must precede them. Therefore the option -f image2 must precede the image sequence given as input.

The frame rate of sound film is 24 fps (frames per second) and the default frame rate of image2 is 25 fps, therefore we have to change it.

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. And for image sequences starting at 086400 (captured at 24 fps with a timecode starting at 01:00:00:00) or at 090000 (captured at 25 fps with a timecode starting at 01:00:00:00), add the flag -start_number 86400 or -start_number 90000 before -i input_file_%06d.ext.

The extension for TIFF files is .tif or maybe .tiff; the extension for DPX files is .dpx (or eventually .cin for old Cineon files). Other file formats are possible.

The video codec is specified by -codec:video, which is usually abbreviated as -c:v (-codec:v or -c:video are also possible). We advise to avoid the alias -vcodec.

We advise to use only the version 3 of FFV1 in production, because versions 0 and 1 are deprecated, the version 2 has never really existed, and the version 4 is currently under development.

A Bash script allowing to perform this transcoding is included in our collection Bash Script for Audiovisual Preservation.

Note

1

The following values are valid:

4 6 9 12 15 16 20 24 25 28 30 35 36 40 42 45 48 49 54 56 60 63 64 66 70 72 77 80
81 84 88 90 91 96 99 100 104 108 110 112 117 120 121 126 130 132 135 140 143 144
150 153 154 156 160 165 168 169 170 176 180 182 187 190 192 195 196 198 204 208
209 210 216 220 221 224 225 228 231 234 238 240 247 252 255 256 260 264 266 270
272 273 276 280 285 286 288 289 294 299 300 304 306 308 312 315 320 322 323 324
325 330 336 340 342 345 350 352 357 360 361 364 368 374 375 378 380 384 390 391
396 399 400 405 408 414 416 418 420 425 432 435 437 440 441 442 448 450 456 459
460 462 464 468 475 476 480 483 484 486 493 494 496 500 504 506 510 513 520 522
525 527 528 529 532 540 544 546 550 551 552 558 560 561 567 570 572 575 576 580
588 589 594 598 600 608 609 612 616 620 621 624 625 627 630 638 640 644 646 648
650 651 660 665 667 672 675 676 680 682 684 690 693 696 700 702 703 704 713 714
720 725 726 728 729 735 736 740 744 748 750 754 756 759 760 768 770 775 777 780
782 783 784 792 798 800 805 806 810 812 814 816 819 825 828 832 836 837 840 841
850 851 858 861 864 868 870 874 875 880 884 888 891 896 897 899 900 902 910 912
918 920 924 925 928 930 936 943 945 946 950 952 957 960 961 962 966 972 975 980
984 986 988 989 990 992 999 1000 1008 1012 1014 1015 1020 1023

2025-02-03