FFmpeg Deinterlace Video ? yadif Guide

Q: Can I detect whether a video is interlaced first?

Yes — `ffmpeg -i in.mp4 -filter:v idet -f null -` analyses 200 frames and reports BFF/TFF/progressive counts. Run only when interlaced flags exceed progressive.

What You’ll Learn

How to deinterlace video with the yadif filter
Differences between mode values (0–3)
How to set field order with the parity option
How to tell whether a video is interlaced
How deinterlacing affects frame rate and what to do about it

Tested with: FFmpeg 6.1 (ubuntu-latest / CI verified)
Platform: Windows / macOS / Linux

What is Interlacing?

Interlaced video splits each frame into odd lines (field 1) and even lines (field 2) and displays them alternately. The format is common in TV broadcasts (NTSC, PAL) and DV camera recordings.

Modern PC and smartphone displays are progressive, so playing interlaced video directly produces combing (interlace artifacts).

Basic Command

ffmpeg -i input.mp4 -vf yadif output.mp4

yadif defaults to mode=0 (one output frame per input frame).

The `mode` Option

ffmpeg -i input.mp4 -vf "yadif=mode=0" output.mp4

mode	Behavior	Frame rate
`0`	Output one frame per input frame	Unchanged
`1`	Output one frame per field	Doubled
`2`	Like `mode=0`, but checks frame type and only processes interlaced frames	Unchanged
`3`	Like `mode=1`, but checks frame type	Up to doubled

mode=0 is usually fine. Use mode=1 when you need 60i → 60p conversion.

60i → 30p (Halve the Frame Rate)

When converting Japanese TV broadcasts (1080i at 60Hz) to 30p:

ffmpeg -i input.mp4 -vf "yadif=mode=0" -r 30 output.mp4

60i → 60p (Preserve the Frame Rate)

ffmpeg -i input.mp4 -vf "yadif=mode=1" output.mp4

mode=1 emits one frame per field, producing 60fps progressive output.

The `parity` Option (Field Order)

ffmpeg -i input.mp4 -vf "yadif=mode=0:parity=0" output.mp4

parity	Description
`-1`	Auto-detect (default, recommended)
`0`	BFF (Bottom Field First) — common in NTSC broadcasts
`1`	TFF (Top Field First) — common in PAL broadcasts and DV

-1 (auto) is usually the right choice.

How to Tell if Video is Interlaced

Use ffprobe to inspect the field order.

ffprobe -v quiet -show_streams -select_streams v:0 input.mp4 | grep field_order

If the output is tt (TFF), bb (BFF), tb, or bt, the video is interlaced. A progressive result means no deinterlacing is needed.

Higher-Quality Alternative to yadif

bwdif (Bob Weaver Deinterlacing Filter) produces better quality than yadif at the cost of more CPU:

ffmpeg -i input.mp4 -vf bwdif output.mp4

Frequently Asked Questions

yadif vs bwdif vs nnedi — which deinterlacer is best?

bwdif is yadif’s improved successor and the modern default. nnedi (neural-net) produces the cleanest result but is much slower. yadif is fine for quick batch jobs.

Should I deinterlace 60i to 30p or 60p?

60p (one progressive frame per field, mode=1) preserves motion fluidity. 30p (mode=0) is half the framerate and looks choppier but matches typical web targets.

Can I detect whether a video is interlaced first?

Yes — ffmpeg -i in.mp4 -filter:v idet -f null - analyses 200 frames and reports BFF/TFF/progressive counts. Run only when interlaced flags exceed progressive.

Will deinterlacing harm progressive footage?

Slightly — deinterlacers blur or duplicate fields they cannot find. Use idet to gate the filter and apply only to confirmed-interlaced streams.

Does deinterlacing change the resolution?

No — output dimensions match the input. Only the field combination changes. If the source is 1080i (1920×1080 interlaced), the output is 1920×1080 progressive.

Tested with ffmpeg 6.1 / Ubuntu 24.04 (GitHub Actions runner) Primary sources: ffmpeg.org/ffmpeg-filters.html#yadif / trac.ffmpeg.org/wiki/Deinterlacing