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https://gitlab.com/lvml/mpv-plugin-excerpt


https://gitlab.com/lvml/mpv-plugin-excerpt

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README 

        
Excerpt creation from within mpv

================================



The excerpt.lua script allows you to quickly create excerpts

from media files, you just have to set begin and end markers.



(written by Lutz Vieweg)



Rationale / Use Case:

=====================



When you shoot video with your own camera, chances are you will

want to retain only ~ 10% of your recordings for actual use

in an edited, final cut.



Using video editors like kdenlive - see http://kdenlive.org/ -

is great for assembling and post-processing your final cut,

but it sucks when you try to use it with huge 3840 x 2160 x 24fps

files that were recorded at 100 MBit/s - you'll want to reduce

the amount of data you have to store and deal with to those

parts of the raw video footage you really need.



Now mpv is a marvellous media player, and for me it is currently

the only player that can replay 4k h.264 video files, as

recorded by my Panasonic camera, with little CPU usage and

no stuttering on my laptop.



Also, mpv is the only software that (by utilizing the h.264

decoder hardware well) can very quickly navigate through video

files - the reaction to seek commands is almost instantaneous,

much unlike with many pure software based editors.



For extracting the relevant excerpts from media files it seemed

like an obvious idea to me to script mpv such that I can just

set the "in" and "out" points for a file, then call "ffmpeg"

as an external executable with the appropriate parameters to

seek to the "in" position and copy the content to a new excerpt

file until the "out" position. Without re-encoding, this process

is very quick and does not loose any quality.



Prerequisites / Installation

============================



In order to use excerpt.lua, you'll need to have the executables



* mpv

* ffmpeg 



ready for execution in your $PATH.



(ffmpeg is probably already installed if you have mpv installed,

as mpv makes use of the ffmpeg libraries.)



Copy the "excerpt_copy" shell script to some directory included

in your $PATH. You might want to modify the excerpt_copy script

if you want something else than simple, key-frame accurate extraction

without re-encoding. If you want to change the names of the destination

excerpt files, you have to change the excerpt.lua script for now.



Usage:

======



First change your working directory to where you want your

video excerpts to be written.



Then just start mpv like this:



mpv --script=/path/to/excerpt.lua -fs --script-opts=osc-layout=bottombar yourmediafile.mp4



Where "yourmediafile.mp4" is of course to be replaced by the file

you actually want to extract from. You can also provide multiple file names,

just press the "Return" key once you're done with a file.



The "-fs" and "--script-opts=osc-layout=bottombar" options are not strictly

required, but IMHO the OSC interface is thus best suited for navigating 

through the files.



After start, the video replay will be paused at the begin.



Use the "left" or "right" cursor keys to seek to the previous/next

frames, and "shift-left" or "shift-right" cursor key to seek to the

previous/next keyframe. You can use the other usual mpv seek features,

too, like the cursor up/down keys, the mouse wheel, the navigation bar

for the mouse etc., and of course you can play/pause pressing the

space bar - whatever you do, just seek to the position where you want your

excerpt to begin.



You can use the "w" and "e" keys to zoom out and in, pressing Ctrl and

left/right/up/down allows to pan around in the zoomed display.



Then press the "i" key to mark the begin (or "in"-position) of the excerpt.



Then seek to the position where you want your excerpt to end, and

press the "o" key to mark the end (or "out"-position) of the excerpt.



You can also seek to the begin or end marks you already set by

pressing shift-i and shift-o.



If you are not satisfied with your begin / end choice, you can

press "i" and "o" again to move the marks to the current position.



Once To actually write the excerpt, press "x".

The excerpt.lua script will create a filename that does not

yet exist in your current working directory, files will be

named "excerpt_000.mp4", "excerpt_001.mp4" etc. by default,

and no existing files will be overwritten.



The actual extraction work is done by invoking the "extract_copy"

shell script, which is given the source file name and the "in"

and "out" position as parameters. The supplied extract_copy

script will use ffmpeg to create the extract, by default without

any re-encoding, and therefore only pricise to the keyframe.

If you want frame-exact extraction, you will have to tell ffmpeg

to re-encode your media file, which of course takes much longer,

and might also lower the quality. So if you plan on post-processing

the excerpts in another software (like kdenlive) anyway, don't

bother with frame-exact extraction and fine tune the in/out positions

using the post-processing software.



Options:

========



## Source file name as base for destination file name



If you do not like the default of naming excerpted files "excerpt_000"

to "excerpt_999" (plus filename extension), but would rather like to

use the source file name as base file name for your excerpts, you can

set the script option excerpt-source-based-filename=1 like this:



 mpv --script-opts=excerpt-source-based-filename=1  ...

 

## Source file name extension as the extension for destination file name



If you do not like the default of using ".mp4" as the extension for

excerpted files, which implies the use of MP4 as the output format

when using the supplied excerpt_copy script, you can use the script option

excerpt-source-based-extension=1 like this:

  

 mpv --script-opts=excerpt-source-based-extension=1 ...



## Play files automatically



If you do not like the default of loading files in paused state you can use the

script option excerpt-no-pause-on-file-loaded=1 like this:

  

 mpv --script-opts=excerpt-no-pause-on-file-loaded=1 ...



Notice that it's possible to supply multiple options using comma-separated

script options, like this:



 mpv --script-opts=excerpt-source-based-filename=1,excerpt-source-based-extension=1 ...



CAVEAT

======



Notice that some default-key bindings of mpv are used for different functions

when mpv-plugin-excerpt is active. For example, the "i" key will set the

"in"-point (the start of the excerpt) rather than showing file statistics.

If you do not like any of these key bindings, just edit the end of the

"excerpt.lua" file, all the key-bindings are there.



DISCLAIMER

==========



This software is provided as-is, without any warranties.



Please notice that it is in an early stage at the moment, there

is probably a lot that can be enhanced.