protrolium/ffmpeg.md

## ffmpeg.md

      
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Converting Audio into Different Formats / Sample Rates

Minimal example: transcode from MP3 to WMA:

ffmpeg -i input.mp3 output.wma
You can get the list of supported formats with:

ffmpeg -formats
You can get the list of installed codecs with:

ffmpeg -codecs
Convert WAV to MP3, mix down to mono (use 1 audio channel), set bit rate to 64 kbps and  sample rate to 22050 Hz:

ffmpeg -i input.wav -ac 1 -ab 64000 -ar 22050 output.mp3

Convert any MP3 file to WAV 16khz mono 16bit:

ffmpeg -i 111.mp3 -acodec pcm_s16le -ac 1 -ar 16000 out.wav

Convert any MP3 file to WAV 20khz mono 16bit for ADDAC WAV Player:

ffmpeg -i 111.mp3 -acodec pcm_s16le -ac 1 -ar 22050 out.wav

cd into dir for batch process:

for i in *.mp3; do ffmpeg -i "$i" -acodec pcm_s16le -ac 1 -ar 22050 "${i%.mp3}-encoded.wav"; done
Picking the 30 seconds fragment at an offset of 1 minute:

In seconds

ffmpeg -i input.mp3 -ss 60 -t 30 output.wav

In HH:MM:SS format

ffmpeg -i input.mp3 -ss 0:01:00 -t 0:00:30 output.wav
Split an audio stream at specified segment rate (e.g. 3 seconds)

ffmpeg -i somefile.mp3 -f segment -segment_time 3 -c copy out%03d.mp3

Extract Audio

ffmpeg -i input-video.avi -vn -acodec copy output-audio.aac 
vn is no video.

acodec copy says use the same audio stream that's already in there.
ffmpeg -i video.mp4 -f mp3 -ab 192000 -vn music.mp3
The -i option in the above command is simple: it is the path to the input file. The second option -f mp3 tells ffmpeg that the ouput is in mp3 format. The third option i.e -ab 192000 tells ffmpeg that we want the output to be encoded at 192Kbps and -vn tells ffmpeg that we dont want video. The last param is the name of the output file.
Replace Audio on a Video without re-encoding.

preferred method

ffmpeg -i INPUT.mp4 -i AUDIO.wav -shortest -c:v copy -c:a aac -b:a 256k OUTPUT.mp4
strip audio stream away from video

ffmpeg -i INPUT.mp4 -codec copy -an OUTPUT.mp4
combine the two streams together (new audio with originally exisiting video)

ffmpeg -i 36.MOV -i 36.wav -map 0:v -map 1:a -c copy -y 36-encoded.mov

or add an offset to audio

ffmpeg -i 36.MOV -itsoffset -0.25 -i 36.wav -map 0:v -map 1:a -c copy -y 36-encoded.mov


You say you want to "extract audio from them (mp3 or ogg)". But what if the audio in the mp4 file is not one of those? you'd have to transcode anyway. So why not leave the audio format detection up to ffmpeg?
To convert one file:
ffmpeg -i videofile.mp4 -vn -acodec libvorbis audiofile.ogg
To convert many files:
for vid in *.mp4; do ffmpeg -i "$vid" -vn -acodec libvorbis "${vid%.mp4}.ogg"; done
You can of course select any ffmpeg parameters for audio encoding that you like, to set things like bitrate and so on.
Use -acodec libmp3lame  and change the extension from .ogg to .mp3 for mp3 encoding.
If what you want is to really extract the audio, you can simply "copy" the audio track to a file using -acodec copy. Of course, the main difference is that transcoding is slow and cpu-intensive, while copying is really quick as you're just moving bytes from one file to another. Here's how to copy just the audio track (assuming it's in mp3 format):
ffmpeg -i videofile.mp4 -vn -acodec copy audiofile.mp3
Note that in this case, the audiofile format has to be consistent with what the container has (i.e. if the audio is AAC format, you have to say audiofile.aac). You can use the ffprobe command to see which formats you have, this may provide some information:
for file in *; do ffprobe $file 2>&1 |grep Audio; done
A possible way to automatically parse the audio codec and name the audio file accordingly would be:
 for file in *mp4 *avi; do ffmpeg -i "$file" -vn -acodec copy "$file".ffprobe "$file" 2>&1 |sed -rn 's/.Audio: (...), ./\1/p'; done 
Note that this command uses sed to parse output from ffprobe for each file, it assumes a 3-letter audio codec name (e.g. mp3, ogg, aac) and will break with anything different.

Encoding multiple files
You can use a Bash "for loop" to encode all files in a directory:
$ mkdir newfiles 

$ for f in *.m4a; do ffmpeg -i "$f" -codec:v copy -codec:a libmp3lame -q:a 2 newfiles/"${f%.m4a}.mp3"; done

ffmpeg -i input.m4a -acodec libmp3lame -ab 128k output.mp3 

m4a to mp3 conversion with ffmpeg and lame
A batch file version of the same command would be:

for f in *.m4a; do ffmpeg -i "$f" -acodec libmp3lame -ab 256k "${f%.m4a}.mp3"; done

Extract Single Image from a Video at Specified Frame

$ vf [ss][filename][outputFileName]

where vf is a custom bash script as follows:

$ ffmpeg -ss $1 -i $2 -qmin 1 -q:v 1 -qscale:v 2 -frames:v 1 -huffman optimal $3.jpg


ss offset = frame number divided by FPS of video = the decimal (in milliseconds) ffmpeg needs i.e. 130.5

Duplicate video n number of times

ffmpeg -stream_loop 3 -i input.mp4 -c copy output.mp4

Merge Multiple Videos

concat demuxer

$ cat mylist.txt

file '/path/to/file1'

file '/path/to/file2'

file '/path/to/file3'


$ ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4
Rotate Video by editing metadata (without re-encoding).

ffmpeg -i input.m4v -map_metadata 0 -metadata:s:v rotate="90" -codec copy output.m4v
Split a Video into Images

$ ffmpeg -i video.flv image%d.jpg
Convert Images into a Video

$ ffmpeg -f image2 -i image%d.jpg imagestovideo.mp4

$ ffmpeg -i image-%03d.png -c:v libx264 -pix_fmt yuv420p test.mp4

$ ffmpeg -r 1/5 -i image-%03d.png -c:v libx264 -vf fps=25 -pix_fmt yuv420p test.mp4

Convert Single Image into a Video

$ ffmpeg -loop 1 -i image.png -c:v libx264 -t 60 -pix_fmt yuv420p -vf scale=1920:1080 out.mp4

Convert non-sequentially named Images in a directory

$ ffmpeg -framerate 30 -pattern_type glob -i '*.jpeg' -c:v libx264 -pix_fmt yuv420p gan-1.mov

Convert image sequence of many different sizes and conform to specific frame size

$ ffmpeg -i image-%04d.jpg -c:v libx264 -pix_fmt yuv420p -vf "scale=max(1280\,a*720):max(1280\,720/a),crop=1280:720" test.mp4
Guarantee aspect ratio from image sequence

$ ffmpeg -i image-%04d.jpg -c:v libx264 -pix_fmt yuv420p -vf "scale=720:-2" test.mp4
Evaluate which ratio to apply for scaling, then scale with the requisite amount of padding

$ ffmpeg -i image-%04d.jpg -c:v libx264 -pix_fmt yuv420p -vf "scale=iw*min(1280/iw\,720/ih):ih*min(1280/iw\,720/ih), pad=1280:720:(1280-iw*min(1280/iw\,720/ih))/2:(720-ih*min(1280/iw\,720/ih))/2" test.mp4


1920 version


$ ffmpeg -i image-%04d.jpg -c:v libx264 -pix_fmt yuv420p -vf "scale=iw*min(1920/iw\,1080/ih):ih*min(1920/iw\,1080/ih), pad=1920:1080:(1920-iw*min(1920/iw\,1080/ih))/2:(1080-ih*min(1920/iw\,1080/ih))/2" test.mp4
Convert .mov (JPEG-A or other codec) to H264 .mp4

ffmpeg -i input.mov -vcodec libx264 -pix_fmt yuv420p output.mp4

Simple FLAC convert

ffmpeg -i audio.xxx -c:a flac audio.flac
Merge Two Mono tracks into Stereo

ffmpeg -i left.wav -i right.wav -codec:a pcm_s16le -strict -2 -filter_complex "[0:a][1:a]amix" -ac 2 output.wav
Mix Stereo to Mono

You can modify a video file directly without having to re-encode the video stream. However the audio stream will have to be re-encoded.


Left channel to mono:
ffmpeg -i video.mp4 -map_channel 0.1.0 -c:v copy mono.mp4


Left channel to stereo:

ffmpeg -i video.mp4 -map_channel 0.1.0 -map_channel 0.1.0 -c:v copy stereo.mp4


If you want to use the right channel, write 0.1.1 instead of 0.1.0.
Trim End of file (mp3)

Here's a command line that will slice to 30 seconds without transcoding:


ffmpeg -t 30 -i inputfile.mp3 -acodec copy outputfile.mp3


Subdivide an audio file by time interval

ffmpeg -i file.wav -f segment -segment_time 5 -c copy out%03d.wav


add a filter to fade in / fade out the segments (created in the above command)

for i in *.wav; do ffmpeg -i "$i" -c pcm_s16le -af "afade=t=in:st=0:d=0.05,afade=t=out:st=0.9:d=0.1" "${i%.wav}-fade.wav"; done

To Encode or Re-encode ?

Do you need to cut video with re-encoding or without re-encoding mode? You can try to following below command.

Synopsis: ffmpeg -i [input_file] -ss [start_seconds] -t [duration_seconds] [output_file]
use ffmpeg cut mp4 video without re-encoding

Example:

ffmpeg -i source.mp4 -ss 00:00:05 -t 00:00:10 -c copy cut_video.mp4

use ffmpeg cut mp4 video with re-encoding

Example:

ffmpeg -i source.mp4 -ss 00:00:05 -t 00:00:10 -async 1 -strict -2 cut_video.mp4

If you want to cut off section from the beginning, simply drop -t 00:00:10 from the command
reduce filesize

Example:

ffmpeg -i input.mov -vcodec libx264 -crf 24 output.mp4


It reduced a 100mb video to 9mb.. Very little change in video quality.
Example:

ffmpeg -i video.mov -vf eq=saturation=0 -s 640x480 -c:v libx264 -crf 24 output.mp4


make a grayscale version and scale to 640x480
Convert MP4 to WEBM

ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 31 -b:v 1M output.webm

more info

Convert MKV to MP4

ffmpeg -i file.mkv


check for streams that you want (video/audio). be sure to convert/specify DTS 6 channel audio stream


ffmpeg -i input.mkv -strict experimental -map 0:0 -map 0:1 -c:v copy -c:a:1 libmp3lame -b:a 192k -ac 6 output.mp4


Add Watermark overlay (png) to the center of a video

ffmpeg -i source.mov -i watermark.png -filter_complex "overlay=x=(main_w-overlay_w)/2:y=(main_h-overlay_h)/2" output.mp4


Reverse a video

ffmpeg -i vid.mp4 -vf reverse reversed.mp4


Concat a video with a reversed copy of itself for ping-pong looping effect

ffmpeg -i input.mp4 -filter_complex "[0:v]reverse,fifo[r];[0:v][r] concat=n=2:v=1 [v]" -map "[v]" output.mp4


Convert to different frame rate while preserving audio sync

ffmpeg -i <input> -filter:v fps=fps=30 <output>


Extract embeded subtitle track from mkv

ffmpeg -i input.mkv -map "0:m:language:eng" -map "-0:v" -map "-0:a" output.srt


Create tiled mosaic from every n-th frame in a video file

ffmpeg -ss 13 -i test.mov -frames 1 -vf "select=not(mod(n\,400)),scale=854:480,tile=8x4" tile.png


Created tiled mosaic by scene change in a video file

$ ffmpeg -i YosemiteHDII.webm -vf "select=gt(scene\,0.4),scale=854:480,tile" -frames:v 1 preview.png


do the same process but export the frames individually


$ ffmpeg -i YosemiteHDII.webm -vf "select=gt(scene\,0.4),scale=854:480" -vsync vfr frame_%04d.png


Convert H.264 to H.265 to correct for iOS Airdrop error message

$ ffmpeg -i input.mp4 -c:v libx265 -vtag hvc1 -c:a copy output.mp4


Add hardcoded subtitles to video

$ ffmpeg -i mymovie.mp4 -vf subtitles=subtitles.srt mysubtitledmovie.mp4

more commands

http://www.catswhocode.com/blog/19-ffmpeg-commands-for-all-needs