[FFmpeg-user] When to determine frames are progressive or interlaced ?

[Christian Ebert]

* Carl Eugen Hoyos on Wednesday, December 19, 2012 at 10:36:22 +0000
> tank pranav <akshar_tank <at> yahoo.com> writes:
>> I would like to know when to determine frames are 
>> progressive or interlaced ?
> 
> (Depending on how you define "interlaced" frames:)
> To the best of my knowledge, only visual inspection 
> tells you, but there is a filter named "idet" that 
> tells you if the video is interlaced.

Hm, a vob file for instance is in all probability interlaced, and
at least it "looks" like in this case for once mediainfo gives
more meaningful info:

$ mediainfo --Inform='Video;%ScanType%' test.vob
Interlaced
$ mediainfo --Inform='Video;%ScanOrder%' test.vob
TFF
$ ffmpeg -i test.vob -filter:v idet -f mpeg -t 3 -y /dev/null
ffmpeg version N-47728-g9e28c7e Copyright (c) 2000-2012 the FFmpeg developers
  built on Dec 11 2012 13:07:24 with gcc 4.0.1 (GCC) (Apple Inc. build 5493)
  configuration: --enable-gpl --enable-version3 --enable-nonfree --disable-network --disable-ffserver --enable-shared --enable-postproc --enable-libx264 --enable-libxvid --enable-libfaac --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libvpx --enable-librtmp --extra-cflags=-I/sw/include --extra-libs=-L/sw/lib
  libavutil      52. 12.100 / 52. 12.100
  libavcodec     54. 79.102 / 54. 79.102
  libavformat    54. 49.101 / 54. 49.101
  libavdevice    54.  3.102 / 54.  3.102
  libavfilter     3. 26.102 /  3. 26.102
  libswscale      2.  1.103 /  2.  1.103
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
[mpeg @ 0x2002620] max_analyze_duration 5000000 reached at 5000000
Guessed Channel Layout for  Input Stream #0.1 : stereo
Input #0, mpeg, from 'test.vob':
  Duration: 00:00:49.27, start: 0.360000, bitrate: 5521 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576 [SAR 16:15 DAR 4:3], 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0xa0]: Audio: pcm_s16be, 48000 Hz, stereo, s16, 1536 kb/s
[mpeg @ 0x2004620] VBV buffer size not set, muxing may fail
Output #0, mpeg, to '/dev/null':
  Metadata:
    encoder         : Lavf54.49.101
    Stream #0:0: Video: mpeg1video, yuv420p, 720x576 [SAR 16:15 DAR 4:3], q=2-31, 200 kb/s, 90k tbn, 25 tbc
    Stream #0:1: Audio: mp2, 48000 Hz, stereo, s16, 128 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video -> mpeg1video)
  Stream #0:1 -> #0:1 (pcm_s16be -> mp2)
Press [q] to stop, [?] for help
frame=   75 fps= 60 q=31.0 Lsize=     258kB time=00:00:02.99 bitrate= 706.5kbits/s dup=21 drop=0
video:206kB audio:47kB subtitle:0 global headers:0kB muxing overhead 1.884260%
Single frame detection: TFF:0 BFF:0 Progressive:59 Undetermined:24
[Parsed_idet_0 @ 0x1e1ac00] Multi frame detection: TFF:0 BFF:0 Progressive:62 Undetermined:21


c
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