How to Make Webms

updated november 2016
MANUALLY

BEFORE:
0. For Debian/*buntu, just "sudo apt-get install ffmpeg"
1. Download ffmpeg from here http://ffmpeg.zeranoe.com/builds/ (static, 32 or 64, whatever, ffmpeg.exe is inside of the "bin" folder)
2. Move ffmpeg to "C:\Users\Anon\" (your videos must be there too)
3. Open the command prompt: press "Windows key + R" and type "cmd" or Start > All Programs > Accessories > Command Prompt.



tl;dr just copy these

# excellent quality, VP8
ffmpeg -i 1.mkv -c:v libvpx -quality good -b:v 3000k -bufsize 1000k -auto-alt-ref 1 -lag-in-frames 25 -threads 3 -an -pass 1 -f webm null
# then
ffmpeg -i 1.mkv -c:v libvpx -quality good -b:v 3000k -bufsize 1000k -auto-alt-ref 1 -lag-in-frames 25 -threads 3 -an -pass 2 -f webm kpop.webm

# ok quality, VP8 (One pass, also used for gifs)
ffmpeg -i 1.mkv -c:v libvpx -quality good -cpu-used 1 -b:v 1000k -bufsize 1000k -auto-alt-ref 1 -lag-in-frames 16 -threads 3 -an -f webm 1.webm


# excellent quality but very slow, VP9 (CHANGE 3000K to you desired bitrate, 3000K-5000K is for a good 720p)
ffmpeg -i 1.mkv -c:v libvpx-vp9 -b:v 3000K -tile-columns 0 -frame-parallel 0 -g 9999 -aq-mode 0 -threads 1 -an -pass 1 -speed 4 -f webm null
ffmpeg -i 1.mkv -c:v libvpx-vp9 -b:v 3000K -tile-columns 0 -frame-parallel 0 -g 9999 -aq-mode 0 -threads 3 -an -pass 2 -speed 0 -auto-alt-ref 1 -lag-in-frames 25 -f webm out.webm

# great quality, good speed, VP9
ffmpeg -i 1.mkv -c:v libvpx-vp9 -b:v 3000K -crf 20 -tile-columns 6 -frame-parallel 1 -threads 3 -an -pass 1 -speed 4 -f webm null
ffmpeg -i 1.mkv -c:v libvpx-vp9 -b:v 3000K -crf 20 -tile-columns 6 -frame-parallel 1 -threads 3 -an -pass 2 -speed 2 -auto-alt-ref 1 -lag-in-frames 25 -f webm out.webm


# notes:
# "-quality best" is not recommended, it slows down the encoding and the improvement of quality is imperceptible
# "-auto-alt-ref 1" and "-lag-in-frames 25" are added on the second pass with VP9

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additional parameters:

# for an exact 3 MB webm (x is the time)
-b:v 25165824/X*0.975 -maxrate 25165824/X*0.975
# sound as vorbis (replace -an with this)
-c:a libvorbis -b:a 128k
# add metadata
-metadata title="title goes here"
# copy the video/audio without encoding (if you just want to resize or something similar; a=audio,v=video)
-acodec copy
-vcodec copy
# target quality, only for vp9 (20 is good, 10 is better, 30 is less good)
-crf 20
# downsampling a 5.1 source to 2.0 with Dolby
-af "aresample=matrix_encoding=dplii" -ac 2
# change the color scheme
-pix_fmt yuv420p

# video filters go right after the file name, separated with commas: -vf yadif=0,ass=1.ass,delogo=...
# scale (-1 is to keep the aspect ratio)
-vf scale=1280:-1
# yet another deinlerlacer, 0 is for 30 fps, 1 is for 60 fps
-vf yadif=1
# add subtitles (ass is the real extension)
-vf ass="/home/anon/that.ass"
# erase some logo, like SBS, KBS, etc (test it first!)
# MBC
-vf delogo=x=1530:y=55:w=300:h=100:band=10
# Mnet
-vf delogo=x=1615:y=70:w=195:h=90:band=10
# slow down
-filter:V "setpts=2.0*PTS"
or 3.0, etc.

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Miscellaneous use of ffmpeg

# convert to huffyuv (lossless video and audio, to later edit; -ss is the time, -t is the duration)
ffmpeg -ss 00:00:00.000 -i 1.mkv -t 00:00:00.000 -c:v huffyuv -acodec pcm_s16le output.mkv