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[[Category:Audio/Video]]
[[en:FFmpeg]]
[[ja:FFmpeg]]
From the project [http://www.ffmpeg.org/ home page]:
:''FFmpeg is a complete, cross-platform solution to record, convert and stream audio and video. It includes libavcodec - the leading audio/video codec library.''
== Package installation ==
Various flavors and related projects can be [[pacman|installed]] from the [[official repositories]] and the [[AUR]]:
* {{Pkg|ffmpeg}} – official package
Notable variants:
* {{AUR|ffmpeg-git}} – development version
* {{AUR|ffmpeg-full}} – built with as much optional features enabled as possible
Forks:
* {{AUR|ffmbc}} – targeted for broadcasting usage
<!-- Why is highlighting the differance in binary name useful? Needs to be replaced with a meaningful description of libav. -->
* {{AUR|libav-git}} – the binary it provides is called {{ic|avconv}} instead of {{ic|ffmpeg}}
== Encoding examples ==
=== Screen cast ===
FFmpeg includes the [http://www.ffmpeg.org/ffmpeg-devices.html#x11grab x11grab] and [http://www.ffmpeg.org/ffmpeg-devices.html#alsa-1 ALSA] virtual devices that enable capturing the entire user display and audio input.
To create {{ic|test.mkv}} with lossless encoding:
$ ffmpeg -f x11grab -video_size 1920x1080 -i $DISPLAY -f alsa -i default -c:v ffvhuff -c:a flac test.mkv
where {{ic|-video_size}} specifies the size of the area to capture. Check the FFmpeg manual for examples of how to change the screen or position of the capture area.
To implicitely encode to a shareable size use :
$ ffmpeg -f x11grab -s 1920x1080 -r 25 -i $DISPLAY -f alsa -i default -c:v libx264 -b:v 200k -s 1280x720 test.mp4
You may want to adjust the parameters (left-to-right): input '''f'''ormat, [input]'''s'''ize, frame'''r'''ate, '''i'''nput (in this case display, but could be a file too), input '''f'''ormat, '''i'''nput, '''c'''odec:'''v'''ideo, '''b'''itrate:'''v'''ideo, [output]'''s'''ize of output. Without context the meaning of the parameters may seem ambigious. See the manpage for the synopsis.
=== Recording webcam ===
FFmpeg supports grabbing input from Video4Linux2 devices. The following command will record a video from the webcam, assuming that the webcam is correctly recognized under {{ic|/dev/video0}}:
$ ffmpeg -f v4l2 -s 640x480 -i /dev/video0 ''output''.mpg
The above produces a silent video. It is also possible to include audio sources from a microphone. The following command will include a stream from the default [[Advanced Linux Sound Architecture|ALSA]] recording device into the video:
$ ffmpeg -f alsa -i default -f v4l2 -s 640x480 -i /dev/video0 ''output''.mpg
To use [[PulseAudio]] with an ALSA backend:
$ ffmpeg -f alsa -i pulse -f v4l2 -s 640x480 -i /dev/video0 ''output''.mpg
For a higher quality capture, try encoding the output using higher quality codecs:
$ ffmpeg -f alsa -i default -f v4l2 -s 640x480 -i /dev/video0 -acodec flac \
-vcodec libx264 ''output''.mkv
=== VOB to any container ===
Concatenate the desired [[Wikipedia:VOB|VOB]] files into a single stream and mux them to MPEG-2:
$ cat f0.VOB f1.VOB f2.VOB | ffmpeg -i - out.mp2
=== x264 lossless ===
The ''ultrafast'' preset will provide the fastest encoding and is useful for quick capturing (such as screencasting):
$ ffmpeg -i input -c:v libx264 -preset ultrafast -qp 0 -c:a copy output
On the opposite end of the preset spectrum is ''veryslow'' and will encode slower than ''ultrafast'' but provide a smaller output file size:
$ ffmpeg -i input -c:v libx264 -preset veryslow -qp 0 -c:a copy output
Both examples will provide the same quality output.
=== x265 ===
In encoding x265 files, you may need to specify the aspect ratio of the file via {{ic|-aspect <width:height>}}. Example :
{{bc|<nowiki> ffmpeg -i input -c:v libx265 -aspect 1920:1080 -preset veryslow -x265-params crf 20 output</nowiki>}}
=== Single-pass MPEG-2 (near lossless) ===
Allow FFmpeg to automatically set DVD standardized parameters. Encode to DVD [[Wikipedia:MPEG-2|MPEG-2]] at ~30 FPS:
$ ffmpeg -i ''video''.VOB -target ntsc-dvd ''output''.mpg
Encode to DVD MPEG-2 at ~24 FPS:
$ ffmpeg -i ''video''.VOB -target film-dvd ''output''.mpg
=== x264: constant rate factor ===
Used when you want a specific quality output. General usage is to use the highest {{ic|-crf}} value that still provides an acceptable quality. Lower values are higher quality; 0 is lossless, 18 is visually lossless, and 23 is the default value. A sane range is between 18 and 28. Use the slowest {{ic|-preset}} you have patience for. See the [https://ffmpeg.org/trac/ffmpeg/wiki/x264EncodingGuide x264 Encoding Guide] for more information.
$ ffmpeg -i ''video'' -c:v libx264 -tune film -preset slow -crf 22 -x264opts fast_pskip=0 -c:a libmp3lame -aq 4 ''output''.mkv
{{ic|-tune}} option can be used to [http://forum.doom9.org/showthread.php?t=149394 match the type and content of the of media being encoded].
=== YouTube ===
FFmpeg is very useful to encode videos and strip their size before you upload them on YouTube. The following single line of code takes an input file and outputs a mkv container.
$ ffmpeg -i ''video'' -c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p -c:a copy ''output''.mkv
For more information see the [https://bbs.archlinux.org/viewtopic.php?pid=1200667#p1200667 forums]. You can also create a shell function {{ic|ytconvert}} which takes the name of the input file as first argument and the name of the .mkv container as second argument. To do so add the following to your {{ic|~/.bashrc}}:
{{bc|<nowiki>
ytconvert() {
ffmpeg -i "$1" -c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p -c:a copy "$2.mkv"
}
</nowiki>}}
See also [https://bbs.archlinux.org/viewtopic.php?pid=1200542#p1200542 Arch Linux forum thread].
=== Two-pass x264 (very high-quality) ===
Audio deactivated as only video statistics are recorded during the first of multiple pass runs:
$ ffmpeg -i ''video''.VOB -an -vcodec libx264 -pass 1 -preset veryslow \
-threads 0 -b 3000k -x264opts frameref=15:fast_pskip=0 -f rawvideo -y /dev/null
Container format is automatically detected and muxed into from the output file extenstion ({{ic|.mkv}}):
$ ffmpeg -i ''video''.VOB -acodec libvo-aacenc -ab 256k -ar 96000 -vcodec libx264 \
-pass 2 -preset veryslow -threads 0 -b 3000k -x264opts frameref=15:fast_pskip=0 ''video''.mkv
{{Tip|If you receive {{ic|Unknown encoder 'libvo-aacenc'}} error (given the fact that your ffmpeg is compiled with libvo-aacenc enabled), you may want to try {{ic|-acodec libvo_aacenc}}, an underscore instead of hyphen.}}
=== Two-pass MPEG-4 (very high-quality) ===
Audio deactivated as only video statistics are logged during the first of multiple pass runs:
$ ffmpeg -i ''video''.VOB -an -vcodec mpeg4 -pass 1 -mbd 2 -trellis 2 -flags +cbp+mv0 \
-pre_dia_size 4 -dia_size 4 -precmp 4 -cmp 4 -subcmp 4 -preme 2 -qns 2 -b 3000k \
-f rawvideo -y /dev/null
Container format is automatically detected and muxed into from the output file extenstion ({{ic|.avi}}):
$ ffmpeg -i ''video''.VOB -acodec copy -vcodec mpeg4 -vtag DX50 -pass 2 -mbd 2 -trellis 2 \
-flags +cbp+mv0 -pre_dia_size 4 -dia_size 4 -precmp 4 -cmp 4 -subcmp 4 -preme 2 -qns 2 \
-b 3000k ''video''.avi
* Introducing {{ic|threads}}={{ic|n}}>{{ic|1}} for {{ic|-vcodec mpeg4}} may skew the effects of [[Wikipedia:Motion_estimation|motion estimation]] and lead to [http://ffmpeg.org/faq.html#Why-do-I-see-a-slight-quality-degradation-with-multithreaded-MPEG_002a-encoding_003f reduced video quality] and compression efficiency.
* The two-pass MPEG-4 example above also supports output to the [[Wikipedia:MPEG-4_Part_14|MP4]] container (replace {{ic|.avi}} with {{ic|.mp4}}).
==== Determining bitrates with fixed output file sizes ====
* (Desired File Size in MB - Audio File Size in MB) '''x''' 8192 kb/MB '''/''' Length of Media in Seconds (s) '''=''' [[Wikipedia:Bitrate|Bitrate]] in kb/s
:* (3900 MB - 275 MB) = 3625 MB '''x''' 8192 kb/MB '''/''' 8830 s = 3363 kb/s required to achieve an approximate total output file size of 3900 MB
=== x264 video stabilization ===
Video stablization using the vbid.stab plugin entails two passes.
==== First pass ====
The first pass records stabilization parameters to a file and/or a test video for visual analysis.
* Records stabilization parameters to a file only
$ ffmpeg -i input -vf vidstabdetect=stepsize=4:mincontrast=0:result=transforms.trf -f null -
* Records stabilization parameters to a file and create test video "output-stab" for visual analysis
$ ffmpeg -i input -vf vidstabdetect=stepsize=4:mincontrast=0:result=transforms.trf -f output-stab
==== Second pass ====
The second pass parses the stabilization parameters generated from the first pass and applies them to produce "output-stab_final". You will want to apply any additional filters at this point so as to aboid subsequent transcoding to preserve as much video quality as possible. The following example performs the following in addition to video stabilization:
* {{ic|unsharp}} is recommended by the author of vid.stab. Here we are simply using the defaults of 5:5:1.0:5:5:1.0
* {{Tip|1=fade=t=in:st=0:d=4}} fade in from black starting from the beginning of the file for four seconds
* {{Tip|1=fade=t=out:st=60:d=4}} fade out to black starting from sixty seconds into the video for four seconds
* {{ic|-c:a pcm_s16le}} XAVC-S codec records in pcm_s16be which is losslessly transcoded to pcm_s16le
$ ffmpeg -i input -vf vidstabtransform=smoothing=30:interpol=bicubic:input=transforms.trf,unsharp,fade=t=in:st=0:d=4,fade=t=out:st=60:d=4 -c:v libx264 -tune film -preset veryslow -crf 8 -x264opts fast_pskip=0 -c:a pcm_s16le output-stab_final
=== Subtitles ===
==== Extracting ====
Subtitles embedded in container files, such as MPEG-2 and Matroska, can be extracted and converted into SRT, SSA, among other subtitle formats.
* Inspect a file to determine if it contains a subtitle stream:
{{hc|$ ffprobe foo.mkv|
...
Stream #0:0(und): Video: h264 (High), yuv420p, 1920x800 [SAR 1:1 DAR 12:5], 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
Metadata:
CREATION_TIME : 2012-06-05 05:04:15
LANGUAGE : und
Stream #0:1(und): Audio: aac, 44100 Hz, stereo, fltp (default)
Metadata:
CREATION_TIME : 2012-06-05 05:10:34
LANGUAGE : und
HANDLER_NAME : GPAC ISO Audio Handler
'''Stream #0:2: Subtitle: ssa (default)}}
* {{ic|foo.mkv}} has an embedded SSA subtitle which can be extracted into an independent file:
$ ffmpeg -i foo.mkv foo.ssa
==== Hardsubbing ====
(instructions based on an [http://trac.ffmpeg.org/wiki/How%20to%20burn%20subtitles%20into%20the%20video FFmpeg wiki article])
[[Wikipedia:Hardsub|Hardsubbing]] entails merging subtitles with the video. Hardsubs can't be disabled, nor language switched.
* Overlay {{ic|foo.mpg}} with the subtitles in {{ic|foo.ssa}}:
$ ffmpeg -i foo.mpg -c copy -vf subtitles=foo.ssa out.mpg
=== Volume gain ===
Change the audio volume in multiples of 256 where '''256 = 100%''' (normal) volume. Additional values such as 400 are also valid options.
-vol 256 = 100%
-vol 512 = 200%
-vol 768 = 300%
-vol 1024 = 400%
-vol 2048 = 800%
To double the volume '''(512 = 200%)''' of an [[Wikipedia:Mp3|MP3]] file:
$ ffmpeg -i ''file''.mp3 -vol 512 ''louder_file''.mp3
To quadruple the volume '''(1024 = 400%)''' of an [[Wikipedia:Ogg|Ogg]] file:
$ ffmpeg -i ''file''.ogg -vol 1024 ''louder_file''.ogg
Note that gain metadata is only written to the output file. Unlike mp3gain or ogggain, the source sound file is untouched.
=== Extracting audio ===
{{hc|$ ffmpeg -i ''video''.mpg|
...
Input #0, avi, from '''video''.mpg':
Duration: 01:58:28.96, start: 0.000000, bitrate: 3000 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 720x480 [PAR 1:1 DAR 16:9], 29.97 tbr, 29.97 tbn, 29.97 tbc
Stream #0.1: Audio: ac3, 48000 Hz, stereo, s16, 384 kb/s
Stream #0.2: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
Stream #0.3: Audio: dts, 48000 Hz, 5.1 768 kb/s
...
}}
Extract the first ({{ic|-map 0:1}}) [[Wikipedia:Dolby_Digital|AC-3]] encoded audio stream exactly as it was multiplexed into the file:
$ ffmpeg -i ''video''.mpg -map 0:1 -acodec copy -vn ''video''.ac3
Convert the third ({{ic|-map 0:3}}) [[Wikipedia:DTS_(sound_system)|DTS]] audio stream to an [[Wikipedia:Advanced_Audio_Coding|AAC]] file with a bitrate of 192 kb/s and a [[Wikipedia:Sampling_rate|sampling rate]] of 96000 Hz:
$ ffmpeg -i ''video''.mpg -map 0:3 -acodec libvo-aacenc -ab 192k -ar 96000 -vn ''output''.aac
{{ic|-vn}} disables the processing of the video stream.
Extract audio stream with certain time interval:
$ ffmpeg -ss 00:01:25 -t 00:00:05 -i ''video''.mpg -map 0:1 -acodec copy -vn ''output''.ac3
{{ic|-ss}} specifies the start point, and {{ic|-t}} specifies the duration.
=== Stripping audio ===
# Copy the first video stream ({{ic|-map 0:0}}) along with the second AC-3 audio stream ({{ic|-map 0:2}}).
# Convert the AC-3 audio stream to two-channel MP3 with a bitrate of 128 kb/s and a sampling rate of 48000 Hz.
$ ffmpeg -i ''video''.mpg -map 0:0 -map 0:2 -vcodec copy -acodec libmp3lame \
-ab 128k -ar 48000 -ac 2 ''video''.mkv
{{hc|$ ffmpeg -i ''video''.mkv|
...
Input #0, avi, from '''video''.mpg':
Duration: 01:58:28.96, start: 0.000000, bitrate: 3000 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 720x480 [PAR 1:1 DAR 16:9], 29.97 tbr, 29.97 tbn, 29.97 tbc
Stream #0.1: Audio: mp3, 48000 Hz, stereo, s16, 128 kb/s
}}
{{Note|Removing undesired audio streams allows for additional bits to be allocated towards improving video quality.}}
=== Splitting files ===
You can use the {{ic|copy}} codec to perform operations on a file without changing the encoding. For example, this allows you to easily split any kind of media file into two
$ ffmpeg -i file.ext -t 00:05:30 -c copy part1.ext -ss 00:05:30 -c copy part2.ext
== Preset files ==
Populate {{ic|~/.ffmpeg}} with the default [http://ffmpeg.org/ffmpeg-doc.html#SEC13 preset files]:
$ cp -iR /usr/share/ffmpeg ~/.ffmpeg
Create new and/or modify the default preset files:
{{hc|~/.ffmpeg/libavcodec-vhq.ffpreset|2=
vtag=DX50
mbd=2
trellis=2
flags=+cbp+mv0
pre_dia_size=4
dia_size=4
precmp=4
cmp=4
subcmp=4
preme=2
qns=2
}}
=== Using preset files ===
Enable the {{ic|-vpre}} option after declaring the desired {{ic|-vcodec}}
==== libavcodec-vhq.ffpreset ====
* {{ic|libavcodec}} '''=''' Name of the vcodec/acodec
* {{ic|vhq}} '''=''' Name of specific preset to be called out
* {{ic|ffpreset}} '''=''' FFmpeg preset filetype suffix
===== Two-pass MPEG-4 (very high quality) =====
First pass of a multipass (bitrate) ratecontrol transcode:
$ ffmpeg -i ''video''.mpg -an -vcodec mpeg4 -pass 1 -vpre vhq -f rawvideo -y /dev/null
Ratecontrol based on the video statistics logged from the first pass:
$ ffmpeg -i ''video''.mpg -acodec libvorbis -aq 8 -ar 48000 -vcodec mpeg4 \
-pass 2 -vpre vhq -b 3000k ''output''.mp4
* '''libvorbis quality settings (VBR)'''
:* {{ic|-aq 4}} = 128 kb/s
:* {{ic|-aq 5}} = 160 kb/s
:* {{ic|-aq 6}} = 192 kb/s
:* {{ic|-aq 7}} = 224 kb/s
:* {{ic|-aq 8}} = 256 kb/s
* [http://www.geocities.jp/aoyoume/aotuv/ aoTuV] is generally preferred over [http://vorbis.com/ libvorbis] provided by [http://www.xiph.org/ Xiph.Org] and is provided by [https://aur.archlinux.org/packages.php?ID=6155 libvorbis-aotuv] in the [[AUR]].
== Package removal ==
[[pacman]] will not [[Pacman#Removing_packages|remove]] configuration files outside of the defaults that were created during package installation. This includes user-created preset files.
== See also ==
* [http://mewiki.project357.com/wiki/X264_Settings x264 Settings] - MeWiki documentation
* [http://ffmpeg.org/ffmpeg-doc.html FFmpeg documentation] - official documentation
* [http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-x264.html Encoding with the x264 codec] - MEncoder documentation
* [http://avidemux.org/admWiki/doku.php?id=tutorial:h.264 H.264 encoding guide] - Avidemux wiki
* [http://howto-pages.org/ffmpeg/ Using FFmpeg] - Linux how to pages
* [http://ffmpeg.org/general.html#Supported-File-Formats-and-Codecs List] of supported audio and video streams