FFmpeg TV vs PC Color Range Explained

When processing video with FFmpeg, understanding the difference between the tv and pc color ranges is crucial for preventing washed-out blacks or clipped highlights. This article explains what these color ranges represent, how they differ in pixel values, and how to correctly apply them in your FFmpeg video conversion workflows.

What is the Difference?

The terms tv and pc refer to how color and brightness values are mapped to digital data in a video signal. The fundamental difference lies in the range of numerical values used to represent black, white, and everything in between.

TV Range (Limited Range)

The tv color range—also known as limited range, broadcast range, or MPEG range—is the historical standard for television broadcasts and analog-to-digital video.

In an 8-bit video system (which has a total of 256 possible values from 0 to 255): * Reference Black is mapped to value 16. * Reference White is mapped to value 235. * Values from 0 to 15 are reserved for “footroom” (to prevent signal clipping), and values from 236 to 255 are reserved for “headroom.”

PC Range (Full Range)

The pc color range—also known as full range or JPEG range—is the standard for computers, mobile devices, and internet-based media.

In an 8-bit system: * Reference Black is mapped to value 0. * Reference White is mapped to value 255. * The entire spectrum from 0 to 255 is utilized to display visual information.

Why Color Range Mismatches Occur

If FFmpeg or a media player does not correctly identify the color range of a video, it will interpret the pixel values incorrectly, leading to two common visual issues:

  1. Washed-Out Colors (Full-to-Limited Mishandling): If a video recorded in pc (full) range is mistakenly interpreted as tv (limited) range, a media player will map the black level (16) and white level (235) to the screen, compressing the range. This makes blacks look dark gray and whites look light gray, giving the video a hazy, washed-out appearance.
  2. Crushed Blacks and Blown-Out Whites (Limited-to-Full Mishandling): If a tv (limited) range video is incorrectly interpreted as pc (full) range, the media player scales the values. Value 16 is stretched down to 0, and 235 is stretched up to 255. This causes “clipping,” where subtle shadow details are lost to pure black and bright highlights are lost to pure white.

Managing Color Ranges in FFmpeg

In FFmpeg, you can explicitly set or convert color ranges using both video filters and output flags.

1. Specifying Color Range in the Scale Filter

The scale filter allows you to force an input range (in_range) and convert it to a specific output range (out_range).

To convert a full-range (pc) video to a limited-range (tv) video:

ffmpeg -i input.mp4 -vf "scale=in_range=pc:out_range=tv" output.mp4

To convert a limited-range (tv) video to a full-range (pc) video:

ffmpeg -i input.mp4 -vf "scale=in_range=tv:out_range=pc" output.mp4

2. Setting Color Range Metadata Flags

Sometimes, the video frames are already in the correct range, but the metadata flag is missing or incorrect, causing media players to render it poorly. You can force the metadata tag without re-encoding the color values using the -color_range option:

To flag the output video as limited range:

ffmpeg -i input.mp4 -c:v libx264 -color_range tv output.mp4

To flag the output video as full range:

ffmpeg -i input.mp4 -c:v libx264 -color_range pc output.mp4