Encode DNxHD Video to MXF Using FFmpeg

This guide provides a straightforward tutorial on how to encode video files into the professional, Avid-compatible DNxHD format inside an MXF container using FFmpeg. You will learn the exact command-line syntax, necessary parameters like bitrates and pixel formats, and how to ensure your output file is fully compatible with major non-linear editing systems (NLEs).

The Basic Command Syntax

The FFmpeg encoder for DNxHD is highly strict. It requires you to match the resolution, frame rate, and bitrate to the official Avid DNxHD specifications. If these parameters do not match, FFmpeg will return an error.

Here is the standard command to encode a 1080p 29.97 fps video to DNxHD 145 (8-bit) inside an MXF container:

ffmpeg -i input.mp4 -c:v dnxhd -b:v 145M -pix_fmt yuv422p -c:a pcm_s16le output.mxf

Key Parameters Explained

• -i input.mp4: Specifies your input source video.
• -c:v dnxhd: Selects the DNxHD video codec.
• -b:v 145M: Sets the video bitrate. For DNxHD, you must choose a valid bitrate standard.
• -pix_fmt yuv422p: Sets the pixel format to yuv422p (8-bit). For 10-bit encoding, use yuv422p10le.
• -c:a pcm_s16le: Encodes the audio to uncompressed 16-bit PCM, which is the broadcast standard for MXF wrappers. Use pcm_s24le for 24-bit audio.
• output.mxf: Specifies the MXF container extension for the output file.

Standard DNxHD Bitrate and Frame Rate Combinations

To avoid FFmpeg encoding errors, you must pair your video’s frame rate and resolution with the correct bitrate. Below are the most common configurations for 1080p video:

For 1080p at 29.97 fps:

• 8-bit (DNxHD 145):

  ffmpeg -i input.mp4 -c:v dnxhd -b:v 145M -pix_fmt yuv422p -c:a pcm_s16le output.mxf

• 10-bit (DNxHD 220x):

  ffmpeg -i input.mp4 -c:v dnxhd -b:v 220M -pix_fmt yuv422p10le -c:a pcm_s24le output.mxf

For 1080p at 23.976 fps (23.98 fps):

• 8-bit (DNxHD 115):

  ffmpeg -i input.mp4 -c:v dnxhd -b:v 115M -pix_fmt yuv422p -c:a pcm_s16le output.mxf

• 10-bit (DNxHD 175x):

  ffmpeg -i input.mp4 -c:v dnxhd -b:v 175M -pix_fmt yuv422p10le -c:a pcm_s24le output.mxf

For 1080p at 25 fps (PAL):

• 8-bit (DNxHD 120):

  ffmpeg -i input.mp4 -c:v dnxhd -b:v 120M -pix_fmt yuv422p -c:a pcm_s16le output.mxf

• 10-bit (DNxHD 185x):

  ffmpeg -i input.mp4 -c:v dnxhd -b:v 185M -pix_fmt yuv422p10le -c:a pcm_s24le output.mxf

Forcing Video Standardization

If your input file does not match standard broadcast resolutions or frame rates, you must force FFmpeg to scale and convert the frame rate during the transcode process.

The following command forces the input file to 1080p resolution at 29.97 fps before applying the DNxHD encoding:

ffmpeg -i input.mp4 -vf "scale=1920:1080,fps=30000/1001" -c:v dnxhd -b:v 145M -pix_fmt yuv422p -c:a pcm_s16le output.mxf