FFmpeg

FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams.

Audio

Audio codecs and bitrates:

• mp3: 128, 144, 160, 192

• vorbis: 128, 144, 160, 192 (ogg)

• aac: 128, 144, 160, 192 (m4a)

• opus: 128, 144, 160, 192 (ogg/opus)

• Audio conversion:

  ffmpeg -i audio.mka -acodec libmp3lame audio.mp3

• Extract audio:

  # -map channel
  ffmpeg -i movie.mkv -vn -map 0:4 -acodec copy output.mka

• Record audio:

  ffmpeg -f alsa -i default output.mka
  
  ffmpeg -f alsa -i default -acodec libopus -threads 0 -y output.mka

Video

• Extract video:

  ffmpeg -i movie.mkv -an -map 0:0 -vcodec copy video.mkv

• Record Video:

  ffmpeg -f x11grab -i :0.0 test.mkv
  
  ffmpeg -f x11grab -i $DISPLAY test.mkv
  
  ffmpeg -f x11grab -video_size 1920x1080 -framerate 25 -i $DISPLAY -c:v ffvhuff screen.mkv

• Audio and Video Recording:

  ffmpeg -f alsa -ac 2 -i default -acodec libopus -threads 0 -y output.mka
  
  ffmpeg -f x11grab -r 20 -s 1920x1080 -i :0.0 -vcodec libx265 -preset fast -b:v 500k -threads 0 -y output.6.mkv
  
  ffmpeg -f alsa -ac 2 -i default -f x11grab -r 20 -s 1920x1080 -i :0.0 -acodec aac -vcodec libx264 -preset ultrafast -b:v 900k -threads 0 -y output.mkv
  
  ffmpeg -f x11grab -video_size 1920x1080 -framerate 25 -i $DISPLAY -f alsa -i default -c:v libx264 -preset ultrafast -c:a aac screen.mp4

• Combine audio and video:

  ffmpeg -i video.mkv -i audio.mp3 -map 0:v -map 1:a -c:v copy -shortest movie.mkv

• Check streams in a file:

  ffprobe -v error -show_entries stream=index,codec_name,codec_type movie.mkv

Images

• Capture screenshot:

  ffmpeg -f x11grab -video_size 1920x1080 -i $DISPLAY -vframes 1 screen.png

x265

x265 is a H.265/HEVC encoder.

An application for encoding video streams into the H.265/MPEG-H HEVC compression format.

Basic Commands

1. Simple encoding:

   x265 inputFile.y4u outFile.hevc

   Only yuv or y4m can be used as input!

2. Encoding Statistics:

   • CLI log:

     --log-level <integer|string>

     where

     value	log-level
     0	error
     1	warning
     2	info (default)
     3	debug
     4	full
     -1	disable

   • Statistics output to file :

     --csv <filename>

     • If --csv-log-level is 0 then one line per run.
     • If greater than 0 then one line per frame.

3. Progress:

   --no-progress

   Disable periodic progress reports from the CLI

Something

I have png images from 0000.png through 0120.png. I want to use ffmpeg to convert them into an mp4 video. The images have an alpha channel, I would like the alpha channel to be composited to the right side of the rgb channels, so that the video has double the width of the input images, with the rgb on the left half and the alpha on the right half. The alpha should be represented as black for 100% transparent and white for 0% transparent

Here is an ffmpeg command that you can use to convert a sequence of png images with an alpha channel into an mp4 video:

ffmpeg -framerate 24 -i %04d.png -vf "split[rgb][a]:[rgb]setpts=PTS-STARTPTS[rgb]:[a]alphaextract.format=gray[alpha]:[rgb][alpha]hstack" -c:v 1ibx264 -crf 23 -preset veryfast output.mp4

This command will convert the png images 0000. png through 0120.png at a frame rate of 24 frames per second. The -vf option specifies the video filterchain that is used to process the images. In this case, the filterchain uses the split filter to split the input images into their red, green, blue (RGB) and alpha channels. The setpts filter is then used to adjust the timing of the RGB channels so that they match the alpha channels. The alphaextract filter is used to extract the alpha channel and convert it to grayscale. The format filter is then used to convert the alpha channel to the desired format (in this case, grayscale). Finally, the hstack filter is used to stack the RGB and alpha channels horizontally, with the RGB channels on the left and the alpha channel on the right. The -c:v option specifies the codec that should be used for the video, and the -crf and -preset options control the quality and encoding speed of the output video

Tools

Build FFmpeg filters: A simple GUI tool to create complex FFmpeg filter-graphs quickly and correctly