ffmpeg detect interlacing

ffmpeg-interlace-test.sh

#!/bin/bash

# for a blogpost on this, check: http://www.aktau.be/2013/09/22/detecting-interlaced-video-with-ffmpeg/

# detect interlacing with the ffmpeg "idet" filter, the longer
# you let this run, the better, though it's never 100% accurate

# flags:
# -an            = discard audio, we don't need it
# -f rawvideo    = output raw video
# -y NUL         = discard the output (one can use /dev/null on UNIX operating systems, NUL works for all)
# -i ...         = the input file to check
# -frames:v 100  = extract the first 100 frames
# -filter:v idet = insert the "idet" filter, which will output whether it has detected interlaced frame

ffmpeg -filter:v idet -frames:v 100 -an -f rawvideo -y NUL -i ~/Downloads/PSY\ -\ Gangnam\ Style\ -\ iHeartRadio\ Music\ Festival\ 2012\ 1080i60\ H.264\ 35Mbps.mkv
# Example output (this is interlaced, TFF style)
# [Parsed_idet_0 @ 0x1ccf7c0] Single frame detection: TFF:167 BFF:0 Progressive:1 Undetermined:0
# [Parsed_idet_0 @ 0x1ccf7c0] Multi frame detection: TFF:168 BFF:0 Progressive:0 Undetermined:0

ffmpeg -filter:v idet -frames:v 100 -an -f rawvideo -y NUL -i ~/Downloads/startrek1.mov
# Example output (this is not interlaced):
# [Parsed_idet_0 @ 0x1bcf720] Single frame detection: TFF:0 BFF:0 Progressive:564 Undetermined:84
# [Parsed_idet_0 @ 0x1bcf720] Multi frame detection: TFF:0 BFF:0 Progressive:623 Undetermined:25

# scan all files, uses GNU parallel
locate -0 '.mov' | parallel -0 ./ffmpeg -filter:v idet -frames:v 100 -an -f rawvideo -y NUL -i {} 2>&1 | egrep 'idet|Input'

Can you share the command to run on windows. because while running its says permission denied.

Code :
res=subprocess.call('ffmpeg -filter:v idet -frames:v 100 -an -f rawvideo -y D:\Inputvideos -i C:\Users\tarun\Desktop\interlacing\Inputvideos\videoplaybackcutv3.mp4')

Output

ffmpeg version N-92486-g8f875a90c4 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 8.2.1 (GCC) 20181017
configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
libavutil 56. 23.101 / 56. 23.101
libavcodec 58. 39.100 / 58. 39.100
libavformat 58. 22.100 / 58. 22.100
libavdevice 58. 6.100 / 58. 6.100
libavfilter 7. 44.100 / 7. 44.100
libswscale 5. 4.100 / 5. 4.100
libswresample 3. 4.100 / 3. 4.100
libpostproc 55. 4.100 / 55. 4.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'C:\Users\tarun\Desktop\interlacing\Inputvideos\videoplaybackcutv3.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.22.100
Duration: 00:00:05.02, start: 0.000000, bitrate: 266 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 170 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 85 kb/s (default)
Metadata:
handler_name : IsoMedia File Produced by Google, 5-11-2011
D:\Inputvideos: Permission denied

D:\Inputvideos should be an existing file.

D:\Inputvideos: Permission denied

On Windows you need to set output to NUL instead of /dev/null

ffmpeg -i video_to_detect.mp4 -filter:v idet -frames:v 100 -an -sn -dn -f rawvideo NUL -y

@cdgriffith this is much better and it works, Thank you!

Thanks all. I've updated the gist.