This repository houses scripts and applications to assist with compressing a video file to a desired size.

ff4d takes a video file as its input and encodes it to be less than a target file size. Discord's free-tier file size sharing limit is 25MB. You can change the file's name in a way that trims the file to a timestamped section. I developed this package specifically for swift sharing of large NVIDIA ShadowPlay clips on Discord, eliminating the need for a visual editor.

The TwoPass() class presents a 2-pass encoding approach for the ffmpeg-python library, which is not showcased in that package's documentation. Additionally, the class extends support to various FFmpeg video filters such as cropping and resolution scaling, making it adaptable to a range of audio/video workflows.

This package works with Python >= 3.8. For Windows users, ensure that Python is added to your system's PATH. I highly recommend that you use the python.org Python installation.

Install this package with the following command.

pip install ffmpeg4discord

You must first have FFmpeg installed on your system. ffmpeg needs to be registered in your PATH. macOS or Linux users can use their favorite package manager to do this, but this process is a little more tricky for Windows users.

After installing this package, Windows users can run this command in a terminal to download the necessary ffmpeg binaries:

install-ffmpeg-windows

This will place ffmpeg.exe, ffprobe.exe, and ffplay.exe into the same location as your Python executable.

Use ff4d in your favorite terminal like this:

ff4d path-to-file.mp4 <optional-flags>

This command tries to compress the whole video file down to the default output file size of 25MB:

ff4d cool_clip.mp4

This will trim a 20 second section out of cool_clip.mp4 starting at 10 seconds in and ending at 30 seconds. More on the optional flags.

ff4d cool_clip.mp4 --from 00:00:10 --to 00:00:30

I've had a good time using this command with a Batch file on Windows. Refer to the Sample Batch File section for more information.

Enable this feature with --filename-times. You can edit the name of your video file if you need to trim it to a specific section. Here are a few examples.

1. 000020.mp4
   • This trims and compresses the video from 00:00:20 to the end of the clip.
2. 000020-000145.mp4
   • This trims and compresses the video from 00:00:20 to 00:01:45.
3. SomethingElse.mp4
   • Compresses the entire video if the first six characters of the file's name aren't numeric.

If your encoding job will always be the same, you can reference a JSON configuration file instead of passing a long list of arguments to the command line.

{
    "target_filesize": 8.0,
    "audio_br": 96,
    "crop": "",
    "resolution": "",
    "codec": "libx264",
    "times": {
        "from": "00:00:00",
        "to": "00:00:40"
    }
}

Notes:

• All of the keys except for "from" and "to" must always be present. Those entries can be deleted if you do not have a timestamp entry for the given field. Examples:
  • "times": {} -> if you do not wish to trim the start and stop time of the file.
  • "times": {"from": "00:00:10"} -> trim the clip from 00:00:10 to the end of the file
  • "times": {"to": "00:00:20"} -> trim the clip from the beginning of the file up to 00:00:20
• You can set audio_br to null if you want to maintain the clip's audio bitrate.

ff4d 000050-000145.mp4 \
    -x 1280x0x2560x1440 \
    -r 1920x1080 \
    -s 50 \
    -a 48 \
    -o D:/shadowplay/ \
    --filename-times

The example above takes a 5120x1440 resolution video as its input. The script trims the video from 00:00:50 to 00:01:45 (specified in the file name, and enabled with --filename-times). It crops a 2560x1440 section starting at 1280 pixels from the top-left and 0 pixels down (-x). The output file will be located in D:/shadowplay/ (-o) with a new resolution of 1920x1080 (-r), and it will be 50MB (-s). The audio bitrate will be reduced to 48k (-a) as well, but that's probably going to sound terrible.

The web UI can be activated by adding --web to your ff4d call.

ff4d cool_clip.mp4 -r 1280x720 -s 20 --web

That command will spin up a Flask server on your local machine and launch a rendered webpage with the video as the centerpiece. The flags you provide to ff4d will fill in the defaults for the form. You can override/replace the values with the web form.

You can drag the video playhead to different portions of the video and click the "Set Start/End Time" buttons to specify the section of the video you want to be clipped out. You can also use the range sliders underneath the buttons if you prefer. A "Preview Selection" button is provided for your convenience, and it does what it sounds like.

Note that the Flask server doesn't automatically shut down, so you'll need to manually terminate it by closing the terminal window where it's running.

To enable "drag and drop" functionality for this package, Windows users can create a .bat file with the following code snippet. Once the file is created, you can drag and drop any .mp4 file on top of it, and it will run with the flags specified in the "Optional Flags" section. This example is a Batch file that will launch the web UI.

@echo off
Set filename=%1
ff4d %filename% -o "C:/output/folder/" --web
PAUSE

Yes, this is a simple collection of Python files using FFmpeg tricks that is masquerading as a robust Audio/Video tool. But! I use this nearly every day to quickly share videos with people on various messaging apps that have built-in video players. I don't have to share a link that embeds a video player this way, and I guess that's important to me?

I like working on this! Enjoy!