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	1 ![blind](blind.svg)
	2
	3 blind is a collection of command line video editing utilities.
	4
	5 Video format
	6 ------------
	7 blind uses a raw video format with a simple container. A file begins wit…
	8 plain-text line, containing the number of frames, the width, the height,…
	9 the pixel format, all separated by a single regular blank space, without…
	10 leading or tailing white space. After this line, which ends with an LF, …
	11 is a NUL-byte followed by the 4 characters “uivf” (unportable, inter…
	12 video format). This head is followed by the video frame-by-frame with ro…
	13 frames. Pixels are independently encoded, and are encoded unscaled CIE X…
	14 non-premultiplied alpha and without any transfer-function, with values s…
	15 in native `double`s or optionally in native `float`s. These two configur…
	16 are the only options, but the container format is designed so this can be
	17 changed arbitrarily in the future.
	18
	19 FAQ
	20 ---
	21
	22 ### Creating videos without graphics, are you insane?
	23
	24 Yes, but see the rationale below!
	25
	26 ### Doesn't raw video takes up a lot of space?
	27
	28 Yes it does, a 4-channel pixel encoded with `double` takes 32 bytes. A
	29 1280-by-720 frame with this pixel format takes 29.4912 MB (SI), which me…
	30 can only fit almost 3391 frames in 100 GB, which is about 113 seconds or…
	31 minutes with a framerate of 30 fps. Therefore, you probably do not want …
	32 store anything in this format unless you know you have room for it, or i…
	33 very small segment of your video, which unfortunately becomes a bit of a…
	34 when reversing a video. However, when possible, feed the resulting video
	35 directly to `blind-to-video` to convert it into a compressed, lossless v…
	36 format, if the video is not too large, you can choose to compress it wit…
	37 instead.
	38
	39 ### For what kind of video editing is blind designed?
	40
	41 It is designed for composing new videos. It is not designed for making s…
	42 changes as this can probably be done faster with a graphical video edito…
	43 with ffmpeg which would also be much faster.
	44
	45 ### Does it support farbfeld?
	46
	47 Of course. If you want to use farbfeld, you can use the `-f` flag for
	48 `blind-to-image` and `blind-from-image`, this will cause the programs to
	49 convert directly to or from farbfeld without using `convert(1)`.
	50
	51 ### Why doesn't blind uses encode pixels like farbfeld?
	52
	53 blind and farbfeld solve completely different problems. farbfeld solves …
	54 problem of storing pictures in a simply way that can easily be viewed and
	55 edited. blind does not try to solve the problem of storing videos, video
	56 takes a lot of space and need compression designed especially for video …
	57 three-dimensional raster images. Compressed video cannot be efficiently …
	58 because compression takes too long. Instead blind solves the problem of
	59 efficiently processing video: thousands of pictures. Because blind doesn…
	60 to create a format for storing images, therefore it's format doesn't nee…
	61 portable. Furthermore, due to legacy in television (namely, that of
	62 black-and-white television), video formats do not store values in sRGB, …
	63 rather in Y'UV, so there is next to no benefit to storing colours in sRG…
	64
	65 ### Why doesn't blind use sRGB?
	66
	67 If I tell you I use CIE XYZ, you will only have two questions: “how are
	68 values stored?” and “is Y scaled to [0, 100] or [0, 1]?” When I te…
	69 I use sRGB you have more questions: “do you support out-of-gamut colou…
	70 “how are values stored?”, “which scale do you use?”, and “is t…
	71 transfer-function applied?”
	72
	73 CIE XYZ also has the advantage of having the brightness encoded in one o…
	74 parameters, Y, and obtaining the chroma requires only simply conversion …
	75 non-standardise colour model that with the same Y-value.
	76
	77 ### Why does blind use CIE XYZ instead of CIE L\a\b\*?
	78
	79 Because CIE L\a\b\* is not linear, meaning that it requires unnecessary
	80 calculations when working with the colours.
	81
	82 ### Why does blind use CIE XYZ instead of Y'UV or YUV?
	83
	84 Y'UV has good performance for converting to sRGB and is has good subsamp…
	85 quality, but it is not a good for editing. Y'UV is non-linear, so it has…
	86 same disadvantages as CIE L\a\b\*. Y'UV does not have its transfer-fun…
	87 applied directly to it's parameters, instead it is a linear transformati…
	88 the sRGB with its transfer-function applied. This means that no performa…
	89 gained during conversion to or from cooked video formats by using YUV. C…
	90 also has the advantage that it is well-known and has a one-step conversi…
	91 almost all colour models. It also have the advantages that it's paramete…
	92 named X, Y, Z, which makes it very easy to choose parameter when storing…
	93 instead of colours in a video.
	94
	95 ### Doesn't blind have any audio support?
	96
	97 No, it is not clear that there is actually a need for this. There are go…
	98 tools for editing audio, and ffmpeg can be used to extract the audio
	99 streams from a video or add it to a video.
	100
	101 ### Is it really feasible to edit video without a GUI?
	102
	103 Depends on what you are doing. Many things can be done without a GUI, and
	104 some thing are easier to do without one. If you find that you need GUI it
	105 possible to combine blind with a graphical editor. Furthermore, blind co…
	106 used in by a graphical editor if one were to write a graphical editor to…
	107 blind.
	108
	109 Rationale
	110 ---------
	111 * It's source control friendly and it's easy for a user to resolve merge
	112 conflicts and identify changes.
	113 * Rendering can take a very long time. With this approach, the user can …
	114 Make to only rerender parts that have been changed.
	115 * It's possible to distribute the rendering to multiple computers, witho…
	116 built in functionality for this, for example using a distributed Make.
	117 * Parallelism is added for free.
	118 * No room for buggy GUIs, which currently is a problem with the large vi…
	119 editors for Linux.
	120 * Less chance that the user makes a change by mistake without noticing i…
	121 as moving a clip in the editor by mistake instead of for example resiz…
	122 * Even old, crappy computers can be used for large projects.
	123 * Very easy to utilise command line image editors for modify frames, or …
	124 your own tools for custom effects.
	125
	126 Development
	127 -----------
	128 You can browse its [source code repository](//git.suckless.org/blind) or…
	129 copy using git with the following command:
	130
	131 git clone https://git.suckless.org/blind
	132
	133 Download
	134 --------
	135 * [blind-1.0](//dl.suckless.org/tools/blind-1.0.tar.gz) (2017-01-22)
	136 * [blind-1.1](//dl.suckless.org/tools/blind-1.1.tar.gz) (2017-05-06)
	137
	138 Also make sure to check your package manager. The following distributio…
	139 provide packages:
	140
	141 * [Alpine Linux](https://pkgs.alpinelinux.org/package/edge/testing/x86_6…
	142 * [Arch Linux (AUR)](https://aur.archlinux.org/packages/blind/)
	143 * [Arch Linux (AUR), git version](https://aur.archlinux.org/packages/bli…
	144
	145 Dependencies
	146 ------------
	147 * [ffmpeg](https://www.ffmpeg.org/) - for converting from or to other vi…
	148 formats.
	149 * [imagemagick](https://www.imagemagick.org/) - for converting regular i…
	150 to frames.
	151
	152 Links
	153 -----
	154 * [Video tutorials](https://www.youtube.com/channel/UCg_nJOURt3guLtp4dQL…
	155
	156
	157 Author
	158 ------
	159 * Mattias Andrée ([email protected])