FFMpeg

Free, open source software for transcoding

#note/sink

TOC

Filters

filters in a chain are separated by commas ","
chains by a semicolon ";"
if an input or output is not specified it is assumed to come from the preceding or sent to the following item in the chain.

"filter1=setting1=value1:setting2=value2,filter2=setting1=value1:setting2=value2"

Scale

The FFmpeg rescaler provides a high-level interface to the libswscale library image conversion utilities. In particular it allows one to perform image rescaling and pixel format conversion.
https://trac.ffmpeg.org/wiki/Scaling https://ffmpeg.org/ffmpeg-scaler.html

iw is input width
-1 and -2 to preserve ratio

ffmpeg -i input -vf "scale=iw/2:-1" output

Libx264

https://trac.ffmpeg.org/wiki/Encode/H.264

To list all possible internal presets and tunes:

@echo off
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -f lavfi -i nullsrc "-c:v libx264" -preset help -f mp4 NUL

chaneru x264 doc

Rate control

There are two rate control modes that are usually suggested for general use:

CRF

The range of the CRF scale is 0–51, where 0 is lossless (for 8 bit only, for 10 bit use -qp 0), 23 is the default, and 51 is worst quality possible. A lower value generally leads to higher quality, and a subjectively sane range is 17–28. Consider 17 or 18 to be visually lossless or nearly so; it should look the same or nearly the same as the input but it isn't technically lossless.

The range is exponential, so increasing the CRF value +6 results in roughly half the bitrate / file size, while -6 leads to roughly twice the bitrate.

Will two-pass provide a better quality than CRF?
​No, though it does allow you to target a file size more accurately.

Two-pass ABR

For two-pass, you need to run ffmpeg twice, with almost the same settings, except for:

When using option -an, you may eventually get a segfault or a broken file. If so, remove option -an and replace by -vsync cfr to the first pass.

Presets

To see a list of current presets with -preset help
If you target a certain file size or constant bit rate, you will achieve better quality with a slower preset. Similarly, for constant quality encoding, you will simply save bitrate by choosing a slower preset.

Libx265

H.265/HEVC

x265 docs

NvEnc

Source
[[Using_FFmpeg_with_NVIDIA_GPU_Hardware_Acceleration.pdf]]
FFmpeg wiki

@REM h264_nvenc help
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=h264_nvenc

Sequence to video

Many high-end video pipelines work with DPX, EXR or TIFF sequences. To transform these sequences into video files, the easiest way is to specify the first file in the sequence as the input and then use -framerate to set the input frame rate and -r to set the output frame rate:

@echo off
ffmpeg -i input_0001.dpx -framerate 59.94 -c:v libx264 -b:v 30M -r 29.97 -an output.mp4

Palettegen

and Paletteuse, dithering options

https://ffmpeg.org/ffmpeg-filters.html#palettegen-1

Getting info and help

For filters, codecs, muxers, etc

@echo off
rem Get encoder help
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=exr

@echo off
rem Get encoder help
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=aac

@echo off
rem Get all pixel formats
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -pix_fmts

@echo off
rem Get pixel formats for encoder
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=libx264 | findstr "pixel"

@echo off
rem Get pixel muxer's private options
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h muxer=apng

@echo off
rem Get pixel muxer's private options
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h muxer=mjpeg

@echo off
rem Get pixel formats for encoder
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=h264_nvenc

@echo off
rem Get pixel formats for encoder
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=hevc_nvenc

@echo off
rem Get pixel formats for encoder
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=libvpx-vp9

@echo off
rem Get pixel formats for encoder
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=mjpeg

@echo off
rem Get pixel formats for encoder
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=png

@echo off
rem Get pixel formats for encoder
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=libx264

@echo off
rem Get pixel formats for encoder
"C:\Program Files\ffmpeg\bin\ffmpeg" -hide_banner -h encoder=libx265

Colorspace conversion

https://trac.ffmpeg.org/wiki/colorspace

FFprobe

Count keyframes

@set "file=D:\Keerah\Projects1\stf tests\thecolour05.mov"
@"C:\Program Files\ffmpeg\bin\ffprobe.exe" -hide_banner -of compact=p=0:nk=1 -select_streams "v:0" -count_frames -show_entries stream=nb_read_frames -skip_frame nokey -v 0 -i "%file%"

Show streams

set "file=D:\Keerah\Projects1\stf tests\Blossom1.0001.puzzleMatte\Blossom1.0001.puzzleMatte_jpeg40.jpg"
@"C:\Program Files\ffmpeg\bin\ffprobe.exe" -v error -hide_banner -show_streams -show_format -sexagesimal -i "%file%"

Format name

set "file=D:\Keerah\Projects1\stf tests\thecolour05.mov"
@"C:\Program Files\ffmpeg\bin\ffprobe.exe" -v error -hide_banner -show_entries "format=format_name" -of "default=noprint_wrappers=1:nokey=1" -sexagesimal -i "%file%"

Get particular stream data

@set "file=D:\Keerah\Projects1\stf tests\thecolour05.mov"
@"C:\Program Files\ffmpeg\bin\ffprobe.exe" -v error -hide_banner -show_entries "stream=width,height,duration,codec_name,pix_fmt,color_space,color_primaries,color_transfer,color_range,avg_frame_rate" -of "default=noprint_wrappers=1" -select_streams "v:0" -sexagesimal -i "%file%"

Progress

Move ffmpeg execution into a separate process? run and fetch progress?

-progress %TEMP%\progr.txt

https://blog.programster.org/ffmpeg-output-progress-to-file

Frameserver

https://www.debugmode.com/frameserver/