20 FFmpeg Commands For Beginners

In this guide, I will be explaining how to use FFmpeg multimedia framework to do various audio and video transcoding, conversion operations with examples. I have compiled most commonly and frequently used 20 FFmpeg commands for beginners. Let us get started, shall we? If you haven’t installed FFmpeg yet, refer the following guide.

• Install FFmpeg in Linux

20 FFmpeg Commands For Beginners

The typical syntax of the FFmpeg command is:

ffmpeg [global_options] {[input_file_options] -i input_url} ...
 {[output_file_options] output_url} ...

We are now going to see some important and useful FFmpeg commands.
1. Getting audio/video file information
To display your media file details, run:

$ ffmpeg -i video.mp4

Sample output:

ffmpeg version 3.3 Copyright (c) 2000-2017 the FFmpeg developers
 built with gcc 6.3.1 (GCC) 20170306
 configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-avisynth --enable-avresample --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libass --enable-libbluray --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxvid --enable-netcdf --enable-shared --enable-version3
 libavutil 55. 58.100 / 55. 58.100
 libavcodec 57. 89.100 / 57. 89.100
 libavformat 57. 71.100 / 57. 71.100
 libavdevice 57. 6.100 / 57. 6.100
 libavfilter 6. 82.100 / 6. 82.100
 libavresample 3. 5. 0 / 3. 5. 0
 libswscale 4. 6.100 / 4. 6.100
 libswresample 2. 7.100 / 2. 7.100
 libpostproc 54. 5.100 / 54. 5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
 Metadata:
 major_brand : isom
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 encoder : Lavf57.22.100
 Duration: 00:43:18.69, start: 0.000000, bitrate: 1039 kb/s
 Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x714 [SAR 1071:1072 DAR 120:67], 899 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
 Metadata:
 handler_name : VideoHandler
 Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 132 kb/s (default)
 Metadata:
 handler_name : SoundHandler
At least one output file must be specified

As you see in the above output, FFmpeg displays the media file information along with FFmpeg details such as version, configuration details, copyright notice, build and library options etc.
If you don’t want to see the FFmpeg banner and other details, but only the media file information, use -hide_banner flag like below.

$ ffmpeg -i video.mp4 -hide_banner

Sample output:

See? Now, it displays only the media file details.

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2. Converting video files to different formats
FFmpeg is powerful audio and video converter, so It’s possible to convert media files between different formats. Say for example, to convert mp4 file to avi file, run:

$ ffmpeg -i video.mp4 video.avi

Similarly, you can convert media files to any format of your choice.
For example, to convert youtube flv format videos to mpeg format, run:

$ ffmpeg -i video.flv video.mpeg

If you want to preserve the quality of your source video file, use ‘-qscale 0’ parameter:

$ ffmpeg -i input.webm -qscale 0 output.mp4

To check list of supported formats by FFmpeg, run:

$ ffmpeg -formats

3. Converting video files to audio files
To convert a video file to audio file, just specify the output format as .mp3, or .ogg, or any other audio formats.
The above command will convert input.mp4 video file to output.mp3 audio file.

$ ffmpeg -i input.mp4 -vn -ab 320 output.mp3

Also, you can use various audio transcoding options to the output file as shown below.

$ ffmpeg -i input.mp4 -vn -ar 44100 -ac 2 -ab 320 -f mp3 output.mp3

Here,

• -vn – Indicates that we have disabled video recording in the output file.
• -ar – Set the audio frequency of the output file. The common values used are  22050, 44100, 48000 Hz.
• -ac – Set the number of audio channels.
• -ab – Indicates the audio bitrate.
• -f – Output file format. In our case, it’s mp3 format.

4. Change resolution of video files
If you want to set a particular resolution to a video file, you can use following command:

$ ffmpeg -i input.mp4 -filter:v scale=1280:720 -c:a copy output.mp4

Or,

$ ffmpeg -i input.mp4 -s 1280x720 -c:a copy output.mp4

The above command will set the resolution of the given video file to 1280×720.
Similarly, to convert the above file to 640×480 size, run:

$ ffmpeg -i input.mp4 -filter:v scale=640:480 -c:a copy output.mp4

Or,

$ ffmpeg -i input.mp4 -s 640x480 -c:a copy output.mp4

This trick will help you to scale your video files to smaller display devices such as tablets and mobiles.
5. Compressing video files
It is always better to reduce the media files size to lower size to save the harddisk’s space.
The following command will compress and reduce the output file’s size.

$ ffmpeg -i input.mp4 -vf scale=1280:-1 -c:v libx264 -preset veryslow -crf 24 output.mp4

Please note that you will lose the quality if you try to reduce the video file size. You can lower that crf value to 23 or lower if 24 is too aggressive.
You could also transcode the audio down a bit and make it stereo to reduce the size by including the following options.

-ac 2 -c:a aac -strict -2 -b:a 128k

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6. Compressing Audio files
Just compressing video files, you can compress audio files using -ab flag in order to save some disk space.
Let us say you have an audio file of 320 kbps bitrate. You want to compress it by changing the bitrate to any lower value like below.

$ ffmpeg -i input.mp3 -ab 128 output.mp3

The list of various available audio bitrates are:

1. 96kbps
2. 112kbps
3. 128kbps
4. 160kbps
5. 192kbps
6. 256kbps
7. 320kbps

7. Removing audio stream from a media file
If you don’t want to a audio from a video file, use -an flag.

$ ffmpeg -i input.mp4 -an output.mp4

Here, ‘an’ indicates no audio recording.
The above command will undo all audio related flags, because we don’t audio from the input.mp4.
8. Removing video stream from a media file
Similarly, if you don’t want video stream, you could easily remove it from the media file using ‘vn’ flag. vn stands for no video recording. In other words, this command converts the given media file into audio file.
The following command will remove the video from the given media file.

$ ffmpeg -i input.mp4 -vn output.mp3

You can also mention the output file’s bitrate using ‘-ab’ flag as shown in the following example.

$ ffmpeg -i input.mp4 -vn -ab 320 output.mp3

9. Extracting images from the video 
Another useful feature of FFmpeg is we can easily extract images from a video file. This could be very useful, if you want to create a photo album from a video file.
To extract images from a video file, use the following command:

$ ffmpeg -i input.mp4 -r 1 -f image2 image-%2d.png

Here,

• -r – Set the frame rate. I.e the number of frames to be extracted into images per second. The default value is 25.
• -f – Indicates the output format i.e image format in our case.
• image-%2d.png – Indicates how we want to name the extracted images. In this case, the names should start like image-01.png, image-02.png, image-03.png and so on. If you use %3d, then the name of images will start like image-001.png, image-002.png and so on.

10. Cropping videos
It is somewhat similar to change the resolution of the video file. let us say you want to a video with size 300×300. You could do that using command:

$ ffmpeg -i input.mp4 -croptop 100 -cropbottom 100 -cropleft 300 -cropright 300 output.mp4

Please note that cropping videos will affect the quality. Do not do this unless it is necessary.
11. Convert a specific portion of a video
Sometimes, you might want to convert only a specific portion of the video file to different format. Say for example, the following command will convert the first 50 seconds of given video.mp4 file to video.avi format.

$ ffmpeg -i input.mp4  -t 50 output.avi

Here, we specify the the time in seconds. Also, it is possible to specify the time in hh.mm.ss format.
12. Set the aspect ratio to video
You can set the aspect ration to a video file using -aspect flag like below.

$ ffmpeg -i input.mp4 -aspect 16:9 output.mp4

The commonly used aspect ratios are:

• 16:9
• 4:3
• 16:10
• 5:4
• 2:21:1
• 2:35:1
• 2:39:1

13. Adding poster image to audio files
You can add the poster images to your files, so that the images will be displayed while playing the audio files. This could be useful to host audio files in Video hosting or sharing websites.

$ ffmpeg -loop 1 -i inputimage.jpg -i inputaudio.mp3 -c:v libx264 -c:a aac -strict experimental -b:a 192k -shortest output.mp4

14. Trim a media file using start and stop times

To trim down a video to smaller clip using start and stop times, we can use the following command.

$ ffmpeg -i input.mp4 -ss 00:00:50 -codec copy -t 50 output.mp4

Here,

• –s – Indicates the starting time of the video clip. In our example, starting time is the 50th second.
• -t – Indicates the total time duration.

This is very helpful when you want to cut a part from an audio or video file using starting and ending time.
Similarly, we can trim down the audio file like below.

$ ffmpeg -i audio.mp3 -ss 00:01:54 -to 00:06:53 -c copy output.mp3

15. Split video files into multiple parts
Some websites will allow you to upload only a specific size of video. In such cases, you can split the large video files into multiple smaller parts like below.

$ ffmpeg -i input.mp4 -t 00:00:30 -c copy part1.mp4 -ss 00:00:30 -codec copy part2.mp4

Here, -t 00:00:30 indicates a part that is created from the start of the video to the 30th second of video. -ss 00:00:30 shows the starting time stamp for the video. It means that the 2nd part will start from the 30th second and will continue up to the end of the original video file.

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16. Joining multiple video parts into one
FFmpeg will also join the multiple video parts and create a single video file.
Create join.txt file that contains the exact paths of the files that you want to join. All files should be same format (same codec). The path name of all files should be mentioned one by one like below.

/home/sk/myvideos/part1.mp4
/home/sk/myvideos/part2.mp4
/home/sk/myvideos/part3.mp4
/home/sk/myvideos/part4.mp4

Now, join all files using command:

$ ffmpeg -f concat -i join.txt -c copy output.mp4

The above command will join part1.mp4, part2.mp4, part3.mp4, and part4,mp4 files into a single file called “output.mp4”.
17. Add subtitles to a video file
We can also add subtitles to a video file using FFmpeg. Download the correct subtitle for your video and add it your video as shown below.

$ fmpeg -i input.mp4 -i subtitle.srt -map 0 -map 1 -c copy -c:v libx264 -crf 23 -preset veryfast output.mp4

18. Preview or test video or audio files
You might want to preview to verify or test whether the output file has been properly transcoded or not. To do so, you can play it from your Terminal with command:

$ ffplay video.mp4

Similarly, you can test the audio files as shown below.

$ ffplay audio.mp3

19. Increase/decrease video playback speed
FFmpeg allows you to adjust the video playback speed. To increase the video playback speed, run:

$ ffmpeg -i inputvideo.mp4 -vf "setpts=0.5*PTS" outputvideo.mp4

To decrease playback speed, run:

$ ffmpeg -i inputvideo.mp4 -vf "setpts=4.0*PTS" outputvideo.mp4

20. Getting help
In this guide, I have merely covered the most commonly used FFmpeg commands. FFmpeg has a lot more different options to do various advanced functions. To learn more about it, refer the man page.

$ man ffmpeg

Source: https://www.ostechnix.com