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Resizing Videos

Resize video files to a different resolution using FFmpeg.

VideoAlchemy Compose File

version: 1

generate_path: "./generated"

tasks:
- name: Resizing Video
  command: ffmpeg
  inputs:
    - id: input_video
      source: 'input.mp4'
      codecs:
    - video_filters:
        - name: scale
          value: "1280:720"
  outputs:
    - id: resized_output
      overwrite: true
      source: 'output.mp4'

Command

ffmpeg -i input.mp4 -vf "scale=1280:720" output.mp4

Parameters

  • -i input.mp4: Specifies the input video file. Replace input.mp4 with the path to your source video file.
  • -vf "scale=1280:720": Applies a video filter to scale the video to the specified width and height. Replace 1280:720 with your desired resolution.
  • output.mp4: Specifies the output video file. Replace output.mp4 with your desired output file name.

Possible Errors

  • File not found: Occurs if FFmpeg cannot locate the input file. Ensure the path to the file is correct.
  • Invalid scale dimensions: Occurs if the specified dimensions are not valid. Ensure that the width and height are positive integers.
  • Permission denied: Occurs if FFmpeg does not have the necessary permissions to read the input file or write to the output file. Ensure that the files and directories have the correct permissions.

GPU Acceleration Command

For Nvidia GPUs, use:

ffmpeg -hwaccel cuda -i input.mp4 -vf "scale_cuda=1280:720" output.mp4

Note: GPU acceleration for video scaling may require specific hardware support and FFmpeg configurations.

Additional Information

  • Aspect Ratio: To maintain the original aspect ratio while scaling, use -1 for one of the dimensions (e.g., scale=1280:-1 to scale the width to 1280 pixels and adjust the height proportionally).
  • Quality: The quality of the resized video can be affected by the scaling algorithm. You can specify the scaling algorithm using the flags option (e.g., scale=1280:720:flags=lanczos for Lanczos resampling).
  • Performance: Resizing videos can be computationally intensive. Using GPU acceleration (if available) can significantly speed up the process.