FFmpeg 4.4

ffmpeg and curl are two open source products I just tip my hat to.

Video to GIF

  SET filters="fps=%4,scale=%3:-1:flags=lanczos"
  ffmpeg -v warning -i %1 -vf "%filters%,palettegen" -y palette.png
  ffmpeg -v warning -i %1 -i palette.png -lavfi "%filters% \[x\]; \[x\]\[1:v\] paletteuse" -y %2
  DEL palette.png

  togif.bat <input.mp4> <output.gif> <width> <fps>

  ffmpeg -i "path\to\my_input_video_file.mp4" "path\to\my_output_audio_only.wav"

  ffmpeg -i "path\to\my_input_video_file.mp4" -map 0:0 -c copy video.mp4 -map 0:1 -c copy audio0.m4a -map 0:2 -c copy audio1.m4a

  (echo file 'first file.mp4' & echo file 'second file.mp4' )>list.txt
  ffmpeg -safe 0 -f concat -i list.txt -c copy output.mp4

  ffmpeg -i input -c:v libx264 -crf 18 -c:a copy output.mkv

  ffmpeg -i input -c:v libx265 -vf format=yuv420p -c:a copy output.mkv

  ffmpeg -i input -c:v libx264 -crf 18 -vf format=yuv420p -c:a copy output.mkv

I have one glorious:

    ffmpeg -hwaccel cuvid -c:v h264_cuvid -i input.mp4 -vf "hwdownload,format=nv12,scale=(iw*sar)*max(1280/(iw*sar)\,720/ih):ih*max(1280/(iw*sar)\,720/ih), crop=1280:720, subtitles=input.srt:force_style='FontName='TiresiasScreenfont',Fontsize=32,Outline=2,MarginL=50,MarginV=30,Alignment=1',minterpolate=fps=60:mi_mode=blend" -c:v h264_nvenc -preset slow -b:v 8M -f matroska - | vlc -

For me I want subtitles with Tiresias screen font used in Finnish YLE 90s. (Aligned always to left second row, so that starting point is always the same. Center alignment is bad because you need to always re-adjust eyes to the position where the subtitles start, left alignment makes the first character always in same place.)

* `hwaccel cuvid -c:v h264_cuvid` * makes the hardware accelerated decoding (h264 only)

* `-vf` * video filter

* `hwdownload,format=nv12` * downloads the hardware accelerated frame to memory for the video filter (required by cuvid)

* `scale=(iwsar)max(1280/(iwsar)\,720/ih):ihmax(1280/(iw*sar)\,720/ih), crop=1280:720` * crops the video to 1280x720, (exteremely high impact on performance!) Use crop and resize cuvid below for better performance.

* `subtitles=input.srt:force_style='FontName='TiresiasScreenfont',Fontsize=32,Outline=2,MarginL=50,MarginV=30,Alignment=1'` * subtitles

* `-c:v h264_nvenc -preset slow -b:v 8M` * hardware accelerated encoding 8000 kb/s for 720p/60 (for 1080p use `16M`)

* `-f matroska * | vlc -` * output as matroska, pipe to VLC

* `minterpolate=fps=60:mi_mode=blend` * output 60 fps interpolate blending (this can cause problems, avoid sometimes)

Crop and resize with cuvid example:

* `-hwaccel cuvid -crop 0x0x200x200` - faster way to crop top x bottom x left x right

* `-hwaccel cuvid -resize 1200x300` - resize (forces the size)

Seek example:

Seek to 30 minutes (60*30 = 1800)

   ffmpeg -ss 1800 ... vf "hwdownload,format=nv12,setpts=PTS+1800/TB,subtitles='...',setpts=PTS-STARTPTS"`

Here are two not present in the comments so far.

Print subtitles (useful for old TVs that can't select a subtitle from streams or files; I use this to get my kids to watch movies in English):

    -vf "ass=subtitle.ass"

    -vf "subtitles=subtitles.srt:force_style='Fontsize=36,PrimaryColour=&H0000FFFF'"

    -vf "select='lt(mod(t,90),1)',setpts=N/FRAME_RATE/TB" -af "aselect='lt(mod(t,90),1)',asetpts=N/SR/TB"

mine:

  h264:
  -c:v libx264 -preset medium -crf 22

  h265:
  -c:v libx265 -preset medium -crf 26

  no recompress:
  -c copy

  presets:
  ultrafast,superfast, faster, fast, medium, slow, slower, veryslow

  desinterlace:
  -vf yadif

  target size:
  -s 1920x1080

  aspect ratio without recompressing:
  -aspect 16:9

  rotate video:
  -vf "transpose=1"
  0 = 90CounterCLockwise and Vertical Flip (default)
  1 = 90Clockwise
  2 = 90CounterClockwise
  3 = 90Clockwise and Vertical Flip

  rotate without recompressing:
  -metadata:s:v rotate="90"

  audio aac two channels:
  -c:a aac -b:a 160k -ac 2

  web fast start:
  -movflags +faststart

  autoscale to WxH with black bands:
  -vf "scale=W:H:force_original_aspect_ratio=decrease,pad=W:H:(ow-iw)/2:(oh-ih)/2"

  get jpeg snapshot:
  -vframes 1 -q:v 2 dest.jpg

  concatenate mp4 without recompressing:
  -f concat -safe 0 -i "files.txt" -c copy -movflags +faststart
  files.txt format:
  file 'filepath'

  ffprobe get videoinfo:
  ffprobe -v quiet -print_format xml -show_format -show_streams "filepath" > file.xml

  if override which sub track is default, use "-default_mode infer_no_subs"

  clear disposition (default sub):
  -disposition:s 0

  default or forced disposition:
  -disposition:s forced

  track metadata (audio):
  -metadata:s:a title="xx"
  track metadata (video):
  -metadata:s:v title="xx"
  global metadata:
  -metadata title="xx"
  -metadata description="xx"
  -metadata comment="xx"

  extract sound from video to mp4
  ffmpeg -i source_video.avi -vn -ar 44100 -ac 2 -ab 192k -f mp3 sound.mp3

  skip time (place after input file):
  -ss 00:05:00

  stop after:
  -t 00:05:00 

  Approx fast seek (place before input file):
  -ss 00:05:00 -noaccurate_seek -i ....

Here's one I wrote a blog post[0] about on how to merge two audio tracks of a video into one track without re-encoding the video:

    ffmpeg -i 'input.mkv' -filter_complex '[0:a:1]volume=0.1[l];[0:a:0][l]amerge=inputs=2[a]' -map '0:v:0' -map '[a]' -c:v copy -c:a libmp3lame -q:a 3 -ac 2 'output.mp4'

Downmixes audio on movies from surround sound to stereo balanced for night watching (prevents audio being too quiet) so that they can direct stream on my devices

  ffmpeg -hide_banner -loglevel error -nostdin -y -i "$f" -map 0:0 -c:v copy -map 0:a:0? -c:a:0 aac -b:a:0 160k -filter:a:0 "pan=stereo|FL=1.414*FC+0.707*FL+0.5*FLC+0.5*BL+0.5*SL+0.5*LFE|FR=1.414*FC+0.707*FR+0.5*FRC+0.5*BR+0.5*SR+0.5*LFE,acompressor=ratio=4" -metadata:s:a:0 title="NightMixed" -metadata:s:a:0 language=eng -disposition:a:0 default -map 0:a:0? -c:a:1 copy -disposition:a:1 none -map 0:a:1? -c:a:2 copy -disposition:a:2 none -map 0:a:2? -c:a:3 copy -disposition:a:3 none -map 0:a:3? -c:a:4 copy -disposition:a:4 none -map 0:a:4? -c:a:5 copy -disposition:a:5 none -map 0:a:5? -c:a:6 copy -disposition:a:6 none -map 0:a:6? -c:a:7 copy -disposition:a:7 none -map 0:a:7? -c:a:8 copy -disposition:a:8 none -map 0:a:8? -c:a:9 copy -disposition:a:9 none -map 0:s:0? -c:s:0 copy -map 0:s:1? -c:s:1 copy -map 0:s:2? -c:s:2 copy -map 0:s:3? -c:s:3 copy -map 0:s:4? -c:s:4 copy -map 0:s:5? -c:s:5 copy -map 0:s:6? -c:s:6 copy -map 0:s:7? -c:s:7 copy -map 0:s:8? -c:s:8 copy -map 0:s:9? -c:s:9 copy "/home/pi/media/remixed_in_progress/$f"

I only have one, and it's for a rather niche use: fixing incorrect or missing h264/h265 bitstream metadata without re-encoding, for example:

    ffmpeg -i source.avc -c copy -bsf:v h264_metadata=colour_primaries=1:matrix_coefficients=1 output.h264

  function grab-screen-lossless {
    ffmpeg -an -f x11grab -video_size 1920x1080 -framerate 60 -i :0.0 -c:v h264_nvenc -preset llhq -tune zerolatency -crf 0 -qp 0 "${1}"
  }
  
  function grab-screen {
    ffmpeg -an -f x11grab -video_size 1920x1080 -framerate 60 -i :0.0 -c:v h264_nvenc -preset llhq -tune zerolatency -qp 10 "${1}"
  }
  
  function vid_compress {
    ffmpeg -i "${1}" -codec:v libx264 -preset:v fast -pix_fmt yuv420p "${2}"
  }

Here's one that generates AppStore previews with correct sizes and metadata. (iTunes Connect can be really picky about this sometimes.)

  # 1. Record your device using QuickTime 
  #  (File->New Movie Recording->Select your phone)
  # 2. Run `$ app-preview your-recording.mov`

  function app-preview() {
      echo "name $1"
      ffmpeg -i $1 -vf scale=1080:1920,setsar=1 -c:a copy "out_$1"
  }

This one just add a 5 second title to the video taking the name from the file name

#!/bin/bash

#Creates a Directory

mkdir -p titles

#loop for files in folder

for f in .MOV; do

    text="${f%.MOV}"     
               

    ffmpeg -i "$f" -vf drawtext="fontfile=/usr/share/fonts/opentype/NotoSansCJK-Regular.ttc  : \

length=$(echo "$duration" | awk '{ split($1, A, ":"); print 3600A[1] + 60*A[2] + A[3] }' )

trim_start="$2"

trim_end=$(echo "$length" - "$3" - "$trim_start" | bc)

ffmpeg -ss "$trim_start" -i "$1" -c copy -map 0 -t "$trim_end" "./trimmed/$1"

# Example # >trim example.MOV 0.2 10

Gladly. There's even some relatively advanced stuff in there:

  # Save a RTSP stream to file
  ffmpeg -i rtps://someserver/somevideo -c copy out.mp4

  # encoding quality settings examples
  #   H264
  ffmpeg -i input.mp4 -a:c copy -c:v libx264 -crf 22 -preset slower -tune film -profile:v high -level 4.1 output.mp4
  #   H264 10bit (must switch to a different libx264 version)
  LD_LIBRARY_PATH=/usr/lib/x86_64-linux-gnu/x264-10bit ffmpeg -i input.mp4 -a:c copy -c:v libx264 -crf 22 -preset slower -tune film -pix_fmt yuv420p10le -profile:v high10 -level 5.0 output.mp4

  # resize 
  ffmpeg -i in.mp4 -s 480x270 -c:v libx264 out.mp4

  # change source fps
  ffmpeg -r 10 -i in.mp4 out.mp4

  # resample fps
  ffmpeg -i in.mp4 -r 10 out.mp4

  # extract the audio from a video
  ffmpeg -i inputfile.mp4 -vn -codec:a copy outputfile.m4a

  # merge audio and video files
  ffmpeg -i inputfile.mp4 -i inputfile.m4a -codec copy outputfile.mp4

  # cut (reencoding)
  #   set the start time and duration as HH:MM:SS
  ffmpeg -ss 00:00:40.000 -i input.mp4 -t 00:00:10 -c:v libx264 output.mp4
  #   set the start time and duration as seconds
  ffmpeg -ss 40.0 -i input.mp4 -t 10.0 -c:v libx264 output.mp4
  #   skip an exact number of frames at the start (100)
  ffmpeg -i input.mp4 -vf 'select=gte(n\,100)' -c:v libx264 output.mp4

  # cut (w/o reencoding - cut times will be approximate)
  ffmpeg -ss 40.0 -i input.mp4 -t 10.0 -c copy output.mp4

  # save all keyframes to images
  ffmpeg -i video.mp4 -vf "select=eq(pict_type\,I)" -vsync vfr video-%03d.png

  # encode video from images (image numbering must be sequential)
  ffmpeg -r 25 -i image_%04d.jpg -vcodec libx264 timelapse.mp4

  # flip image horizontally
  ffmpeg -i input.mp4 -vf hflip -c:v libx264 output.mp4

  # crop and concatenate 3 videos vertically
  ffmpeg -i cam_4.mp4 -i cam_5.mp4 -i cam_6.mp4 -filter_complex "[0:v]crop=1296:432:0:200[c0];[1:v]crop=1296:432:0:200[c1];[2:v]crop=1296:432:0:230[c2];[c0][c1][c2]vstack=inputs=3[out]" -map "[out]" out.mp4

  # 2x2 mosaic (all inputs must be same size)
  ffmpeg -i video1.mp4 -i video2.mp4 -i video3.mp4 -i video4.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[row1];[2:v][3:v]hstack=inputs=2[row2];[row1][row2]vstack=inputs=2[out]" -map "[out]" out.mp4

  # picture-in-picture
  ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "[1:v]scale=iw/3:ih/3[pip];[0:v][pip]overlay=main_w-overlay_w-20:main_h-overlay_h-20[out]" -map "[out]" out.mp4

  # print framerate of every file in dir
  for f in *.mp4; do echo $f; mediainfo $f|grep "Frame rate"; done

  # print selected info of every file in dir in CSV format
  for f in *.mp4; do echo -n $f,; mediainfo --Inform="Video;%Duration%,%FrameCount%,%FrameRate%" $f; done

Convert all FLAC files in the directory to MP3s, in parallel using fd:

    fd -t f -e flac . "$@" -x ffmpeg -loglevel 16 -i "{}" -qscale:a 0 "{.}.mp3"

Test patterns:

  ffmpeg -f lavfi -i testsrc=d=60:s=1920x1080:r=24,format=yuv420p -f lavfi -i sine=f=440:b=4 -b:v 1M -b:a 192k -shortest output-testsrc.mp4

  ffmpeg -f lavfi -i testsrc2=d=60:s=1920x1080:r=24,format=yuv420p -f lavfi -i sine=f=440:b=4 -b:v 1M -b:a 192k -shortest output-testsrc.mp4

  ffmpeg -f lavfi -i smptebars=d=60:s=1920x1080:r=24,format=yuv420p -f lavfi -i sine=f=440:b=4 -b:v 1M -b:a 192k -shortest output-smptebars.mp4

    $cat ~/bin/ffmpeg_grab_desktop.sh
    #!/bin/bash

    size=${1:-"1920x1080"}
    offset=${2:-"0,0"}
    name=${3:-"video"}

    ffmpeg -video_size $size -framerate 25 -f x11grab -i :0.0+$offset -c:v libx264 -crf 0 -preset ultrafast "$name.mkv"
    ffmpeg -i "$name.mkv" -movflags faststart -pix_fmt yuv420p "$name.mp4"

Very Carefully Rebuild a Video

# H264

    $ ffmpeg -i input.avi -c copy -c:v libx264 -crf 18 -preset slow output.mkv

    -c:v libx265 -crf 22

    $ ffmpeg -i input.mkv -i input.srt -map 0 -map 1 -c copy output.mkv

    $ ls *.mkv > mylist.txt
    $ vim mylist.txt # append each line with "file "
    $ ffmpeg -f concat -i mylist.txt -c copy merged-pre-subbed.mkv

     $ ffmpeg -analyzeduration 2147483647 -probesize 2147483647 ...

    -vf yadif

    ffmpeg -i foo.avi -i commentary.mp3 -map 0 -map 1 -c:a copy -c:v libx264 -crf 18 -preset fast  -metadata:s:a:1 title="Commentary" -metadata:s:a:0 language=eng  funk.mkv

    $ ffplay -i foo.mkv -vf "cropdetect=24:16:0"

    <let it run for a minute>

    [Parsed_cropdetect_0 @ 0x7ff093c65c00] x1:0 x2:1919 y1:132 y2:947 w:1920 h:816 x:0 y:132 pts:30155 t:30.155000 crop=1920:816:0:132

    -filter:v:0 "crop=1920:816:0:132"

Not an ffmpeg wizard here, but here are my screencasting commands. Probably the most useful knowledge in this snippet is how to use Alsa from ffmpeg; i.e., Alsa devices can be referred to as hw:0, hw:1, etc; and one finds out which device to use from arecord.

  # Example output file.
  f=/tmp/output.mp4

  # Example video resolution.
  g=1920x1080

  # Example capture framerate
  fr=4

  # Example X11 display
  d=$DISPLAY

  # Simple screencast.
  #
  # Try adjusting the libx264 CRF from 15 to some greater number, as long
  # as there is no visible effect on video quality.
  #
  # If increasing the capture framerate, you may also wish to use a
  # faster preset.
  ffmpeg  -probesize 50M  -f x11grab -video_size "$g" -framerate "$fr" -i "$d"    \
         -c:v libx264 -crf 15 -preset veryslow   "$f"

  # Simple screencast without drawing the pointer/cursor.
  ffmpeg  -probesize 50M  -f x11grab -video_size "$g" -framerate "$fr" -draw_mouse 0 -i "$d"      \
         -c:v libx264 -crf 15 -preset veryslow   "$f"

  # See what devices are available for capturing sound.
  arecord -l

  # Select a device.
  audioCaptureDevice=hw:0

  # List some permitted parameters associated with device 0.
  #
  # We are interested in the "FORMAT", "CHANNELS", and "RATE" parameters
  # for use in the ffmpeg command.
  arecord --dump-hw-params -D "$audioCaptureDevice"

  audioSampleFormat=pcm_s32le
  audioNumChannels=2
  audioRate=44100

  f=/tmp/output.mp3

  # Record sound.
  ffmpeg  -thread_queue_size 8192 -f alsa -channels "$audioNumChannels" -sample_rate "$audioRate" \
         -c:a "$audioSampleFormat" -ar "$audioRate" -i "$audioCaptureDevice" "$f"

  f=/tmp/output.mkv

  # Screencast with sound.
  #
  # Note that there seems to be an FFMPEG bug where the audio in the last
  # 15 seconds of the video is cut off. The workaround is to record for
  # 15 exrtra seconds, and then cut the extra video.
  ffmpeg  -probesize 50M  -f x11grab -video_size "$g" -framerate "$fr" -i "$d"                    \
         -thread_queue_size 8192 -f alsa -channels "$audioNumChannels" -sample_rate "$audioRate" \
         -c:a "$audioSampleFormat" -ar "$audioRate" -i "$audioCaptureDevice"                     \
         -c:a flac -c:v libx264 -crf 17          "$f"

  Convert AVI to MP4
  ----------------------------
  ffmpeg -i input.avi -c:v libx264 -crf 19 -preset slow -c:a libvo_aacenc -b:a 192k -ac 2 out.mp4

  Convert MP4 to GIF
  ---------------------------
  mkdir frames
  ffmpeg -i video.mp4  -r 5 'frames/frame-%03d.jpg'
  cd frames
  convert -delay 20 -loop 0 -layers Optimize *.jpg myimage.gif

I have none. But I do gave HandBrake installed.

I wrote a command-line based video editing tool as a 300-line bash script. It reads a list of segments of video (source file, start position, length) to string together (including options such as image overlay, fade, fast forward, slow motion, static image) from a text file, and converts it into a Makefile with ffmpeg commands in it, which you can then run with whatever level of parallelism you wish. It treats the video and sound separately, and creates a video and sound file for each segment, using concatenatable formats for both. Then the final few make targets are to concatenate the video into one file, the sound into another file, and then multiplex them into a single file. Used it a few times for editing my own videos. It's a bit big to share here though.

# Encode for Apple, 720p

ffmpeg -i snow.mp4 -c:v libx265 -preset slow -crf 28 -tag:v hvc1 -c:a aac -ac 2 -b:a 128k -vf scale=1280:-1 snow.mov

# Merge video from one file, audio from another, trimmed

ffmpeg -i video.mp4 -i audio.mp4 -c:v copy -c:a aac -map 0:v:0 -map 1:a:0 -to 00:00:41 merged.mp4

# Trim a video

ffmpeg -ss 00:06:58 -to 00:08:26 -i TeSiJmLoJd0.webm bbf.mp4

Annotate video with frame numbers:

  ffmpeg -i input.mp4 -vf "drawtext=fontfile=font.ttf: text=%{n}: x=48: y=48: fontcolor=white: box=1: boxcolor=0x00000099: fontsize=72" -y output.mp4

  ffmpeg -i input.mp4 -c copy -an output.mp4

avi2gif:

    ffmpeg -i $1 -vf scale=320:-1:flags=lanczos,fps=10 /tmp/frames/ffout%03d.png
    convert -loop 0 /tmp/frames/ffout*.png $1.gif

    parallel-moreutils -i -j$(nproc) ffmpeg -i {} -qscale:a 0 {}.mp3 -- ./*.flac
    rename .flac.mp3 .mp3 ./*.mp3

    TIMESTAMP=`date +"%Y-%m-%d_%H"`
    TMP_AVI=$(mktemp /tmp/outXXXXXXXXXX.avi)
    ffcast -s % ffmpeg -y -f x11grab -show_region 1 -framerate 15 \
    -video_size %s -i %D+%c -codec:v huffyuv                  \
    -vf crop="iw-mod(iw\\,2):ih-mod(ih\\,2)" $TMP_AVI         \
    && convert -set delay 10 -layers Optimize $TMP_AVI /home/nemo/Desktop/GIFs/$TIMESTAMP.gif

split-by-audible[1] to split a audiobook from Audible to multiple files by chapters using the copied timestamps from the Audible Web Player.

split-by-silence[2] to split audiobooks by Silence instead

audiobook2video[3] to generate a video file from audiobooks. Puts up a nice cover.

[0]:https://github.com/captn3m0/Scripts/blob/master/split-audio-...

[1]: https://github.com/captn3m0/Scripts/blob/master/split-by-aud...

[2]: https://github.com/captn3m0/Scripts/blob/master/split-by-sil...

[3]: https://github.com/captn3m0/Scripts/blob/master/audiobook2vi...

Cut ffmpeg video without losing quality by keeping the same codecs, very fast:

Example: Start at 52 seconds, take 10 minutes after that:

  ffmpeg -ss 52 -i input.mp4 -c copy -t 00:10:00.0 output.mp4

I store my list of ffmpeg shortcuts on a website called StackOverflow

Indeed! Here is my collection of FFmpeg CLIs: https://github.com/kdeldycke/kevin-deldycke-blog/blob/main/c...

    ffmpeg -i foo.mp4 -c:v h264_videotoolbox -b:v 1600k foo_out.mp4

Here is mine.

To screen capture every 600 frames:

  ffmpeg -i my_vid.mp4 -vf "select=not(mod(n\,600))" -vsync vfr -q:v 15 img_%03d.jpg

  for d in \*
  do
      (montage -mode concatenate -tile 4x -resize 1024x $d"/\* "$d".jpg)
  done

All I have that I'm not seeing elsewhere in the replies is:

ffmpeg -r 1 -loop 1 -i 1.png -i 1.wav -c:v libvpx -c:a libvorbis -b:a 64k -shortest out.webm (clearly this is old)

-max_muxing_queue_size 2048 (magically fixes some errors and microscopically increases quality, a no-brainer on machines with more than token amounts of RAM)

There is tldr: https://github.com/tldr-pages/tldr/blob/master/pages/common/...

-pix_fmt yuv420p

Every damn time I have to export from after effects and need a file I can actually open.

Back in 2004, someone released an unauthorized fan dub/narration of the the first Harry Potter movie called Wizard People, Dear Reader that hilariously butchers the entire plot, character names, and motivations. This narration is (loosely) synced to the movie and its scenes, and for a long time I watched it via clips uploaded to YouTube. But when Sorcerer’s Stone got a 4K release, I decided it was time to rip it and create my own canonical copy.

The original audio files of the dub were at this point still available on archive.org. The problem is that the second audio file is not meant to play directly after the first - this was back in the days of CD players, so halfway through the movie the dub instructs you to begin playing the second CD once the next scene starts. The other problem is that the second file is louder than the first.

Most sources I saw online said to insert a gap of three seconds to account for the delay, and didn’t have a solution for the difference in volume. I wanted to be more precise.

First, I found the exact start time of the scene where the second audio track begins:

    ffprobe hp.mkv
    ...
        Chapter #0:18: start  4428.882000, end 4817.521000
        Metadata:
          title           : Chapter 19
    ...

    ffprobe wiz1.mp3
    ...
      Duration: 01:13:45.33, start: 0.000000, bitrate: 66 kb/s
    ...

I then compared the maximum audio levels of the two audio tracks to determine the level to increase the first track’s volume by (there are more advanced features in FFmpeg for volume normalization, but I just wanted to remove the potential for eardrum damage when beginning Chapter 19 and keep things as similar as possible otherwise):

    ffmpeg -i wiz1.mp3 -af volumedetect -f null -
    [Parsed_volumedetect_0 @ 000001ecf871c1c0] max_volume: -11.1 dB

    ffmpeg -i wiz2.mp3 -af volumedetect -f null -
    [Parsed_volumedetect_0 @ 000001858b881880] max_volume: -3.6 dB

Once I had these numbers, it was time for the one-liner to adjust the first track’s volume, concatenate the two tracks with the gap of silence, and mux them with the video from the movie:

    ffmpeg -i hp.mkv -i wiz1.mp3 -i wiz2.mp3 -filter_complex "[1]volume=7.5dB[wiz1];aevalsrc=0:duration=3.582:sample_rate=22050[gap];[wiz1][gap][2]concat=n=3:v=0:a=1,apad[wiz]" -map 0 -map "[wiz]" -shortest -c:v copy -c:a flac -sample_fmt s16 -f matroska wiz.mkv

Extract audio from all my downloaded YT .webm videos to .opus:

  for i in *.webm ; do echo "$i";ffmpeg -i "$i" -acodec copy -vn "${i%.*}.opus" ; done

mov2gif:

    ffmpeg -i input.mov -vf "fps=10,scale=600:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" -loop 0 output.gif

slow down by 10x (gopro 240fps to 24fps)

ffmpeg -i ${1} -sn -an -c:v libx264 -r 24 -filter:v "setpts=10PTS" -crf 19 ${1}-10x.mkv

reverse video

ffmpeg -i $IFILE -s 3840x2160 -f image2 -q:v 1 -vf format=yuvj420p $tmpdir/p%8d.jpg cat $(ls -t $tmpdir/p.jpg) | ffmpeg -f image2pipe -c:v mjpeg -r 30 -i - -c:v libx264 -crf 18 -vf format=yuv420p -preset slow -f mp4 $OFILE

loop a video: loopcount=$1

ffmpeg -stream_loop $1 -i $2 -c copy $3.mkv

I wonder if ffmpeg should have a scripting language and/or repl

It’s a lot like how Linux supports the N64, right? If someone wants to write and maintain the code, it can get upstreamed.

What you can actually do with these extensions?

are you planning to show the ffmpeg command that will be used in the background, I would like to try it out.

The use cases are so diverse that adding a UI for all use cases is near impossible. I also built a UI for ffmpeg, but mine was geared towards creating and applying video filters - much like Lightroom presets.

Is the goal to be simpler to use than StaxRip?

Sadly we are still incredibly lacking in encoding. It's been years since hevc encoding was included in consumer graphics cards and embeddable devices. For one reason or another vendors just haven't done av1 on the hardware level.

For a typical 1080p "linux iso" what filesize difference will there be between x265 and av1?

Looking at the comments in that ticket, I can understand why ffmpeg developers don't want to help those people, and the devs probably spoiled more time answering this annoying person than it would take to have fixed the issue, making them lose all motivation to work on that issue.

Yes, they are listed here: http://ffmpeg.org/index.html#pr4.4

This is why I also use MP4Box, as it's often a lot easier to get something done that I just can't manage to with ffmpeg.

It's a simple, 1-bit image format, used by MS Paint before it switched to BMP.

https://www.fileformat.info/format/mspaint/egff.htm

Support for decoding MS Paint images, see https://ffmpeg.org/ffmpeg-all.html#Image-Formats

Not only did they enable the gopher protocol (whitelist) but they added TLS for it too. https://git.ffmpeg.org/gitweb/ffmpeg.git?a=search&h=n4.4&st=...

ffmpeg-python is used at my workplace so if you've ever cleaned up the docs, or submitted a patch, you have my greatest thanks! Saved my ass big time a couple weeks ago.

It needs both hardware and driver support. You can check supported formats using vdpauinfo. Nouveau maintains a list of supported formats for different hardware at https://nouveau.freedesktop.org/VideoAcceleration.html (I don't think HEVC is supported by nouveau on any hardware.)

Its not merged into homebrew yet: https://github.com/Homebrew/homebrew-core/pull/74849