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ffmpeg/ffprobe

  1. Trim video

    ffmpeg -i input.mp4  -ss 00:00:00 -to 00:00:15 -c:v copy -c:a copy output.mp4

    This command trim video from 00:00:00 to 00:00:15 (final duration = 15 sec).

    The -c:v copy -c:a copy commands copy the original audio and video without re-encoding.

    CAUTION! This way may cause add black frames in the head of a video.

    How to deal with the black screen

    The black screen at the beginning of your video is bound to spoil this lovely story. Here’s how to avoid a black screen

    Use the “-avoid_negative_ts make_zero”  parameter

    What you do here is to pass that part that reads “zero” to avoid any negative section. i.e “make_zero” to “avoid_negative_ts”

    Hence, the video timestamp will be shifted to “0”. So, if the time you specified didn’t fall into the rightful place, it will automatically be corrected to begin at the “start” point.

    ffmpeg -i input.mp4  -ss 00:00:15 -to 00:00:20 -c:v copy -c:a copy -avoid_negative_ts make_zero output.mp4

    Another way to deal with black screen problem is replace seek parameter

    ffmpeg -ss 00:00:15 -i input.mov -to 00:00:20 -c copy -avoid_negative_ts make_zero output.mov

    So, to workaround this effect run a command with no copy video and audio. For example:

    ffmpeg -i input.mp4 -ss 00:00:00 -to 00:00:15 output.mp4

  2. **Removing the first seconds** ffmpeg -ss 00:05 -i input.mp4 -c:v libx264 -c:a aac output.mp4

Removing the first seconds without re-encoding ffmpeg -ss 00:05 -i input.mp4 -c:v copy -c:a copy output.mp4

  1. Speed up video

    ffmpeg -i input.mp4 -r 60 -vf "setpts=0.5*PTS" output.mp4

  2. Shrink big MP4 video file to smaller sizes

    • 3.6 Gb to 556 Mb, great quality 🥇

    ffmpeg -i input.mp4 -vcodec h264 -acodec mp2 output.mp4

    • 3.6 Gb to 62 Mb, quality "good enough"/acceptable 👍

    ffmpeg -i input.mp4 -s 1280x720 -acodec copy -y output.mp4

    • 3.6 Gb to 30 Mb, very shitty quality 💩

    ffmpeg -i input.mp4 -vcodec h264 -b:v 1000k -acodec mp3 output.mp4

    • CPU transcoding to 720p with hevc codec

    ffmpeg -i input.mov -s 1280x720 -vcodec hevc -acodec copy -y output_720p.mov

    • GPU transcoding to 720p with hevc codec

    ffmpeg -y -vsync 0 -hwaccel cuda -hwaccel_output_format cuda -i input.mov -vf scale_cuda=1280:720 -c:a copy -c:v hevc_nvenc output_720p_hevc_nvenc.mov

  3. Create video from images

    MacOS: Add pixel format.

    ffmpeg -framerate 10 -i filename-%03d.jpg -pix_fmt yuv420p output.mp4

    ffmpeg -framerate 10 -pattern_type  glob -i "filename-*.jpg" -pix_fmt yuv420p output.mp4

  4. Concatenate videos

    Create txt file with list of videos:

    for f in *.mov; do echo "file '$f'" >> videos.txt; done

    Concat videos:

    ffmpeg -f concat -i videos.txt -c copy output_[concated.mov](http://concated.mov/)

  5. Get 1 frame from video

    1. With the seek option

      ffmpeg -ss 00:00:01 -i input.mov -frames:v 1 output.jpeg

    2. With select filter

      ffmpeg -i input.mov -vf "select=eq(n\,34)" -frames:v 1 output.jpeg

  6. Get every N frame from video

    • It will get 1 frame every 10 seconds instead of 1 frame every 1 second ffmpeg -i out1.avi -r 0.1 -f image2 image-%3d.jpeg
    • If you really what every 10th frame from video then you can use select with modulo 10 ffmpeg -i out1.mp4 -vf "select=not(mod(n\,10))" -vsync vfr image_%03d.jpg

  7. Get fps from video

    ffprobe -v error -select_streams v:0 -show_entries stream=r_frame_rate -of default=noprint_wrappers=1:nokey=1 input/training_sessions/140048_15sec/140048_4_2023-05-24_15.14.42_15sec_sync.mov | bc -l

  8. Convert mov to mp4 ffmpeg -i input.mov -crf 0 output.mp4

  9. Obtain certain information about video file ffprobe -v error -select_streams v:0 -show_entries stream=width,height,duration,bit_rate -of default=noprint_wrappers=1 input.mp4

  10. Convert mp3 to wav ffmpeg -i file.mp3 -acodec pcm_s16le -ac 1 -ar 22050 file.wav This command generate wav file with shorter duration

  11. Show audio file info ffmpeg -i file.wav -hide_banner

  12. How to generate a sine wave with ffmpeg? ffmpeg -f lavfi -i "sine=frequency=15000:sample_rate=48000:duration=0.5" -c:a mp3 -b:a 192k -af "volume=40dB" 15kHz40.mp3

  13. **Changing volume**

To change the audio volume, you may use FFmpeg's volume audio filter.

If we want our volume to be half of the input volume:

`ffmpeg -i input.wav -filter:a "volume=0.5" output.wav`

150% of current volume:

`ffmpeg -i input.wav -filter:a "volume=1.5" output.wav`

You can also use decibel measures. To increase the volume by 10dB:

`ffmpeg -i input.wav -filter:a "volume=10dB" output.wav`

To reduce the volume, use a negative value:

`ffmpeg -i input.wav -filter:a "volume=-5dB" output.wav`

Note that the `volume` filter only **adjusts** the volume. It does not **set** the volume. To set or otherwise normalize the volume of a stream, see the sections below.

  1. Concat two audio files ffmpeg -i file1.mp3 -i file2.mp3 -filter_complex "[0:a][1:a]concat=n=2:v=0:a=1" final.mp3

  2. Encode a high quality MP3 or MP4 audio from a movie file ffmpeg -i sample.avi -q:a 0 -map a sample.mp3

  3. Trim audio file

    ffmpeg -i a.mp3 -ss 00:00:00 -to 00:05:00 b.mp3

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