A Guide To Video And Audio Conversion Using FFmpeg

Table of Contents

• Install ffmpeg
• Convert between different video formats
• Convert video to audio
• Add Text Subtitles to a Video
• Create gif from video
• Mix video and audio
• Extract part of the video
• Contact multiple videos
• Selecting your codecs for conversion
• Reduce the size of the video
• Extract images from video
• Convert images into a video
• Add images to audio
• Option Lists
• More Tips about ffmpeg
• Online Tools

Install ffmpeg

• brew install ffmpeg at MacOs.
• sudo apt install ffmpeg
• ffmpeg -version to check the version.
• It provides 3 commands
  • ffmpeg
  • ffplay: a minimalistic player for testing ffmpeg
  • ffprobe: a simple analysis tool to inspect multimedia content.

Convert between different video formats

• just specify the input video file, and the output video file with correct suffix, ffmpeg automatically selects the correct codecs.
• ffmpeg supports conversion for most video types: avi, rmvb, mp4, webm, mkv, mpg, flv, dv, mpeg (used by dvd player)
• ffmpeg -codecs to list all supported files.

ffmpeg -i input.rmvb output.mp4
ffmpeg -i input.rmvb input.mp4

Convert video to audio

ffmpeg -i input.mp4 output.mp3
ffmpeg -i input.mp4 -vn output_audio.ogg

Add Text Subtitles to a Video

ffmpeg -i input.mp4 -i subtitles.srt -c copy -c:s mov_text output.mp4

Create gif from video

• ffmpeg -i input.mp4 hide_banner output.gif
  • the file would be huge

Mix video and audio

ffmpeg -i input.mp3 -i input_video.mp4 output.mp4

Extract part of the video

• -ss -t
• Start: where you want the video to start splitting. The format used is hours:minutes:seconds (00:00:00).
• Duration: the total duration of the video you want to split. The format used is hours:minutes:seconds (00:00:00).

Contact multiple videos

• ffmpeg -f concat -safe 0 -i mylist.txt -c copy output

Selecting your codecs for conversion

• -c:a audio_codec
• -c:v video_codec
• -c:a copy, -c:v copy, -c:av:copy
  • use same audio, video or both codec

Reduce the size of the video

• -s “size”: set video resolution size (Width x Height)
• -b: set the bitrate
• -r: sets the framerate
• Use ffmpeg -i input.mp4 to get info about the video

We can use ffplay command to test the effect.

Crop a video

• the format of crop: width:height:left:top.
• -vf means video filter

ffmpeg -i input.mp4 -vf "crop=760:430:520:0" output.mp4

Resize a video

• -vf “scale=300:-1”
• scale=width:height
• -1 tells ffmpeg to automagically calculate

Rotate a video

• -vf “rotate=90”
• ffmpeg -i input.mp4 -vf "rotate=90" -c:a copy out.mp4

Extract images from video

• -r fps: Set frame rate (default 25)
• ffmpeg -i input.mp4 image%d.jpg: this will generate a lot of images

Convert images into a video

ffmpeg -f image2 -i image%d.jpg output.mp4

Add images to audio

ffmpeg -loop 1 -i 1.webp -i input.mp3 -c:v libx264 -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2" -c:a aac -strict experimental -shortest output.mp4

Option Lists

• -vn disables the video
• -acodec copy allows to copy the audio stream without touching it
• -an: disables audio
• -s “size”: set video resolution size (Width x Height)

More Tips about ffmpeg

• Record audio and video from webcam using ffmpeg
• Create a screencast

Online Tools

https://file-converter-online.com/ https://rmvb-to-mp4.file-converter-online.com/