David's Wiki

FFmpeg: Difference between revisions

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* Linux: [https://johnvansickle.com/ffmpeg/ https://johnvansickle.com/ffmpeg/]
* Linux: [https://johnvansickle.com/ffmpeg/ https://johnvansickle.com/ffmpeg/]
* Windows: [https://ffmpeg.zeranoe.com/builds/ https://ffmpeg.zeranoe.com/builds/]
* Windows: [https://ffmpeg.zeranoe.com/builds/ https://ffmpeg.zeranoe.com/builds/]
If you need nvenc support, you can build FFmpeg with https://github.com/markus-perl/ffmpeg-build-script.


Basic usage is as follows:
Basic usage is as follows:
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</syntaxhighlight>
</syntaxhighlight>


However, Ruofei has a more advanced script below:
If you want better quality, you can use the following filter_complex:
{{hidden | Ruofei's MP4 to GIF |
<pre>
<syntaxhighlight lang="bash">
[0]split=2[v1][v2];[v1]palettegen=stats_mode=full[palette];[v2][palette]paletteuse=dither=sierra2_4a
#!/bin/sh
</pre>
start_time=0:0
duration=17
 
palette="/tmp/palette.png"
 
filters="fps=15,scale=320:-1:flags=lanczos"
 
ffmpeg -v warning -ss $start_time -t $duration -i $1.mp4 -vf "$filters,palettegen" -y $palette
ffmpeg -v warning -ss $start_time -t $duration -i $1.mp4 -i $palette -lavfi "$filters [x]; [x][1:v] paletteuse" -y $1.gif
</syntaxhighlight>
}}


Here is another script from [https://superuser.com/questions/556029/how-do-i-convert-a-video-to-gif-using-ffmpeg-with-reasonable-quality https://superuser.com/questions/556029/how-do-i-convert-a-video-to-gif-using-ffmpeg-with-reasonable-quality]
Here is another script from [https://superuser.com/questions/556029/how-do-i-convert-a-video-to-gif-using-ffmpeg-with-reasonable-quality https://superuser.com/questions/556029/how-do-i-convert-a-video-to-gif-using-ffmpeg-with-reasonable-quality]
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</syntaxhighlight>
</syntaxhighlight>
}}
}}
===Pipe to stdout===
Below is an example of piping the video only to stdout:
<pre>
ffmpeg -i video.webm -pix_fmt rgb24 -f rawvideo -
</pre>
In Python, you can read it as follows:
<syntaxhighlight lang="python">
video_width = 1920
video_height = 1080
ffmpeg_process = subprocess.Popen(ffmpeg_command,
                                  stdout=subprocess.PIPE,
                                  stderr=subprocess.PIPE)
raw_image = ffmpeg_process.stdout.read(
              video_width * video_height * 3)
image = (np.frombuffer(raw_image, dtype=np.uint8)
          .reshape(video_height, video_width, 3))
</syntaxhighlight>


==Filters==
==Filters==
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===Stack and Unstack===
===Stack and Unstack===
To stack, see <code>hstack</code>, <code>vstack</code>.   
To stack, see [https://ffmpeg.org/ffmpeg-all.html#hstack <code>hstack</code>], [https://ffmpeg.org/ffmpeg-all.html#vstack <code>vstack</code>].   
To unstack, see <code>crop</code>.
To unstack, see <code>crop</code>.


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Add a background to transparent images.<br>
Add a background to transparent images.<br>
<pre>
<pre>
ffmpeg -i in.mov -filter_complex
ffmpeg -i in.mov -filter_complex "[0]format=pix_fmts=yuva420p,split=2[bg][fg];[bg]drawbox=c=white@1:replace=1:t=fill[bg];[bg][fg]overlay=format=auto" -c:a copy new.mov
      "[0]split=2[bg][fg];[bg]drawbox=c=blue@1:replace=1:t=fill[bg];
</pre>
        [bg][fg]overlay=format=auto" -c:a copy new.mov
 
===Draw Text===
https://stackoverflow.com/questions/15364861/frame-number-overlay-with-ffmpeg
<pre>
ffmpeg -i input -vf "drawtext=fontfile=Arial.ttf: text='%{frame_num}': start_number=1: x=(w-tw)/2: y=h-(2*lh): fontcolor=black: fontsize=20: box=1: boxcolor=white: boxborderw=5" -c:a copy output
</pre>
</pre>


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==JavaScript API==
==JavaScript API==
To use FFmpeg in a browser, see [https://ffmpegwasm.github.io/ ffmpegwasm].   
To use FFmpeg in a browser, see [https://ffmpegwasm.netlify.app/ ffmpegwasm].   
Note: I have not tried this. It uses CLI commands, not library API commands.
This is used in https://davidl.me/apps/media/index.html.


==My Preferences==
==My Preferences==
My preferences for encoding video
My preferences for encoding video
===H264===
I mostly use H264 when working on projects for compatibility purposes. Here I typically don't need the smallest file size or best quality, prioritizing encoding speed.
<syntaxhighlight lang="bash">
!#/bin/bash


ffmpeg -i $1 -c:v libx264 -crf 28 -preset medium -pix_fmt yuv420p -c:a libfdk_aac -b:a 128K $2
===AV1===
</syntaxhighlight>
Prefer AV1 for encoding video on on modern devices.


;Notes
* MP4 is ok


===H265/HEVC===
===H265/HEVC===
H264/HEVC is used for archival purposes to minimize the file size and maximize the quality.
H264/HEVC is now a good tradeoff between size, quality, and compatibility.
This has been supported on devices since Android 5.0 (2014).
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
!#/bin/bash
ffmpeg -i $1 -c:v libx265 -crf 23 -preset slow -pix_fmt yuv444p10le -c:a libopus -b:a 128K $2
ffmpeg -i $1 -c:v libx265 -crf 23 -preset slow -pix_fmt yuv444p10le -c:a libopus -b:a 128K $2
</syntaxhighlight>
</syntaxhighlight>


;Notes
;Notes
* You need to output to a MKV file
* The pixel format <code>yuv444p10le</code> is 10 bit color without chroma subsampling. If your source is lower, you can use <code>yuv420p</code> instead for 8-bit color and 4:2:0 chroma subsampling.
* The pixel format <code>yuv444p10le</code> is 10 bit color without chroma subsampling. If your source is lower, you can use <code>yuv420p</code> instead for 8-bit color and 4:2:0 chroma subsampling.


===AV1===
===H264===
If you need compatability with very old and low end devices.
<syntaxhighlight lang="bash">
ffmpeg -i $1 -c:v libx264 -crf 28 -preset medium -pix_fmt yuv420p -c:a libfdk_aac -b:a 128K $2
</syntaxhighlight>
 
===Opus===
 
For streaming:
<syntaxhighlight lang="bash">
ffmpeg -i input.wav -c:a libopus -b:a 96k output.opus
</syntaxhighlight>
 
See https://wiki.xiph.org/Opus_Recommended_Settings
Retrieved from "https://wiki.davidl.me/view/FFmpeg"