ffmpeg-progress-yield

Run an ffmpeg command with its progress yielded.

Contents:

• Requirements
• Installation
• Usage
  • As a library
  • On the command line
• Caveats
• Contributors
• License

Requirements

• Python 3.9 or higher
• ffmpeg v3.1 or above from http://ffmpeg.org/ installed in your $PATH

Installation

If you want to use the CLI only, via uv:

uvx ffmpeg-progress-yield

Or install via pipx.

To install the library:

pip3 install --user ffmpeg-progress-yield

Usage

As a library

In your Python project, import the helper class, instantiate a context manager, and run run_command_with_progress.

For more information see the API documentation.

Example:

from ffmpeg_progress_yield import FfmpegProgress

cmd = [
    "ffmpeg", "-i", "test/test.mp4", "-c:v", "libx264", "-vf", "scale=1920x1080", "-preset", "fast", "-f", "null", "/dev/null",
]

with FfmpegProgress(cmd) as ff:
    for progress in ff.run_command_with_progress():
        print(f"{progress}/100")

The command will yield the current progress in percent as a float number.

run_command_with_progress takes a duration_override argument where you can manually override the duration of the command in seconds. This is useful if your input doesn't have an implicit duration (e.g. if you use testsrc).

If you have tqdm installed, you can create a fancy progress bar:

from tqdm import tqdm
from ffmpeg_progress_yield import FfmpegProgress

cmd = [
    "ffmpeg", "-i", "test/test.mp4", "-c:v", "libx264", "-vf", "scale=1920x1080", "-preset", "fast", "-f", "null", "/dev/null",
]

with FfmpegProgress(cmd) as ff:
    with tqdm(total=100, position=1, desc="Test") as pbar:
        for progress in ff.run_command_with_progress():
            pbar.update(progress - pbar.n)

    # get the output
    print(ff.stderr)

You can also quit the command early on by calling .quit():

with FfmpegProgress(cmd) as ff:
    for progress in ff.run_command_with_progress():
        if progress > 50:
            ff.quit()
            break

This will send a hard quit to the ffmpeg process, and may not wait for it to finish. Your encoded file may have truncated data. To quit gracefully, use .quit_gracefully() instead, which sends 'q' to the ffmpeg process, and waits for it to finish (e.g., wait for an encoder to flush its buffers).

This is probably most useful in asynchronous environments, where you can run the command in a separate thread, and quit it from the main thread (e.g. using a Condition Variable).

Process Cleanup and Context Manager Support

The library automatically handles process cleanup to prevent lingering ffmpeg processes. It provides multiple layers of safety:

1. Automatic cleanup: Processes are automatically cleaned up even if exceptions occur during iteration
2. Context manager support: Use with statements for guaranteed cleanup
3. Finalizer fallback: Processes are cleaned up during garbage collection as a last resort

On the command line

Simply prefix your ffmpeg command with ffmpeg-progress-yield:

ffmpeg-progress-yield ffmpeg -i input.mp4 output.mp4

It will show a progress bar, and once the command is done, show the ffmpeg stderr output.

Full usage notes:

usage: ffmpeg-progress-yield [-h] [-d DURATION] [-n] [-p] [-x] [-l LOG_FILE] [--ffprobe-path FFPROBE_PATH] ...

ffmpeg-progress-yield v0.12.0

positional arguments:
  ffmpeg_command        Any ffmpeg command. Do not quote this argument.

options:
  -h, --help            show this help message and exit
  -d, --duration DURATION
                        Duration of the video in seconds (override). (default: None)
  -n, --dry-run         Print ffmpeg command and exit. (default: False)
  -p, --progress-only   Print progress only and do not print stderr at exit. (default: False)
  -x, --exclude-progress
                        Exclude progress lines from ffmpeg log. (default: False)
  -l, --log-file LOG_FILE
                        Send ffmpeg log output to specified file. (default: None)
  --ffprobe-path FFPROBE_PATH
                        Path to ffprobe executable (for duration probing). (default: ffprobe)

Duration override

If you want to manually override the duration to, say, 12.5 seconds (e.g. because your input doesn't have an implicit one):

ffmpeg-progress-yield --duration 12.5 ffmpeg -f lavfi -i testsrc -t 12.5 output.mp4

Exclude progress from the CLI

You can also redirect the output to a log file:

ffmpeg-progress-yield --exclude-progress --log-file log.txt ffmpeg -i input.mp4 output.mp4

This will exclude the progress bar from the output, and redirect it to a log file.

Caveats

Currently, we do not differentiate between stderr and stdout. This means progress will be mixed with the ffmpeg log, unless you use --exclude-progress (or exclude_progress in the Python API).

You can also check out ffmpeg-progress for a similar project with a different feature set.

Contributors

Werner Robitza 💻	WyattBlue 💻	Kirill Konovalov 💻	Jason Nader 🐛	Launch Lee 💻	scufre 💻	Alexander Sulfrian 💻
Add your contributions

License

The MIT License (MIT)

Copyright (c) 2021-2025 Werner Robitza

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.