[FFmpeg-user] Question about framecount

[Fabian Schmidt]

Sorry, here’s the images again:

> Westerbork_Film_6479.jpg (showing a frame count of 6739)

https://ibb.co/9qgvqzS

> Westerbork_Film_2171.jpg: (showing a frame count of 2259)

https://ibb.co/jWsSynJ

__

PhD candidate at Filmuniversität Babelsberg, Germany

latest publication: http://www.apparatusjournal.net/index.php/apparatus/article/view/223/515

new research project: VHH - Visual History of the Holocaust: Rethinking Curation in the Digital Age <https://ef.huji.ac.il/book/vhh-visual-history-holocaust-rethinking-curation-digital-age>
currently working for Ludwig Boltzmann Institute for Digital History (LBIDH)  <https://geschichte.lbg.ac.at/team/fabian-schmidt>and Filmuniversität Babelsberg KONRAD WOLF
upcoming research project: DFG-Filmikonen  <https://www.filmuniversitaet.de/filmuni/aktuelles/news/artikel/detail/filmbilder-aus-der-nazizeit-im-fokus>
filmproject: Atrocity Film <http://blog.atrocityfilm.com/>
IMDB <https://www.imdb.com/name/nm1144289/>


Fabian Schmidt
Husemannstr. 12
10435 Berlin
0049 0172 3256513

> On 5. Jun 2021, at 09:43, Fabian Schmidt <fabian.schmidt at filmuniversitaet.de> wrote:
> 
> Dear Mailing list peers!
> 
> I am currently using ffmpeg in order to produce screenshots of each new scene in archival footage. The name of the screenshot is supposed to include the framcount and I want to make a screenshot 3 frames after the cut so my commandline looks like this:
> 
> ffmpeg -i WESTERBORK_2019_progres.mov -filter:v "select=if(gt(scene\,0.13)\,st(1\,n)-n\,if(ld(1)\,eq(n\,ld(1)+3))),showinfo" -vsync vfr  Westerbork_Film_%05d.jpg
> 
> Even though this worked the last two films with my current material I get a stange output. The timecode in the name is roughly 4% higher that the one I burnt in to the videofile (for orientation). Examples:
> 
> 
> Westerbork_Film_6479.jpg:
> 
> 
> 
> Westerbork_Film_2157.jpg:
> 
> 
> This happens with every version (I remuxed the file in mkv toolnix and speded it down to 16 fps and to 25fps) I made. So, even though I doubt it will help, here’s the media info of the file. It’s a silent film; the file is an export from Davinci resolve where I added the frame count:
> 
> 
> General
> Complete name                            : WESTERBORK_2019_progres.mov
> Format                                   : MPEG-4
> Format profile                           : QuickTime
> Codec ID                                 : qt   0000.02 (qt  )
> File size                                : 8.90 GiB
> Duration                                 : 1 h 12 min
> Overall bit rate mode                    : Variable
> Overall bit rate                         : 17.6 Mb/s
> Encoded date                             : UTC 2021-06-04 18:51:26
> Tagged date                              : UTC 2021-06-04 18:51:26
> Writing application                      : Blackmagic Design DaVinci Resolve
> 
> Video
> ID                                       : 1
> Format                                   : AVC
> Format/Info                              : Advanced Video Codec
> Format profile                           : High at L4
> Format settings                          : CABAC / 2 Ref Frames
> Format settings, CABAC                   : Yes
> Format settings, Reference frames        : 2 frames
> Codec ID                                 : avc1
> Codec ID/Info                            : Advanced Video Coding
> Duration                                 : 1 h 12 min
> Bit rate mode                            : Variable
> Bit rate                                 : 17.3 Mb/s
> Maximum bit rate                         : 768 kb/s
> Width                                    : 1 920 pixels
> Height                                   : 1 080 pixels
> Display aspect ratio                     : 16:9
> Frame rate mode                          : Constant
> Frame rate                               : 25.000 FPS
> Color space                              : YUV
> Chroma subsampling                       : 4:2:0
> Bit depth                                : 8 bits
> Scan type                                : Progressive
> Bits/(Pixel*Frame)                       : 0.333
> Stream size                              : 8.74 GiB (98%)
> Encoded date                             : UTC 2021-06-04 18:51:26
> Tagged date                              : UTC 2021-06-04 18:51:26
> Color range                              : Limited
> Color primaries                          : BT.709
> Matrix coefficients                      : BT.709
> Codec configuration box                  : avcC
> 
> Audio
> ID                                       : 2
> Format                                   : AAC LC
> Format/Info                              : Advanced Audio Codec Low Complexity
> Codec ID                                 : mp4a-40-2
> Duration                                 : 1 h 12 min
> Bit rate mode                            : Constant
> Bit rate                                 : 320 kb/s
> Channel(s)                               : 2 channels
> Channel layout                           : L R
> Sampling rate                            : 48.0 kHz
> Frame rate                               : 46.875 FPS (1024 SPF)
> Compression mode                         : Lossy
> Stream size                              : 166 MiB (2%)
> Default                                  : Yes
> Alternate group                          : 1
> Encoded date                             : UTC 2021-06-04 18:51:26
> Tagged date                              : UTC 2021-06-04 18:51:26
> 
> Other
> ID                                       : 3
> Type                                     : Time code
> Format                                   : QuickTime TC
> Duration                                 : 1 h 12 min
> Frame rate                               : 25.000 FPS
> Time code of first frame                 : 01:00:00:00
> Time code, striped                       : Yes
> Language                                 : English
> Default                                  : No
> Encoded date                             : UTC 2021-06-04 18:51:26
> Tagged date                              : UTC 2021-06-04 18:51:26
> 
> 
> Looking forward to hear any tips or comments. Also one more question to the experts: Sometimes ffmepg puts out the frame count in the name with 000 in front and sometimes not. I guess it has something to do with the %05d or %d in the end. Where can I find an explanation how this works?
> 
> Kind regards
> Fabian
> 
> __
> 
> PhD candidate at Filmuniversität Babelsberg, Germany
> 
> latest publication: http://www.apparatusjournal.net/index.php/apparatus/article/view/223/515
> 
> new research project: VHH - Visual History of the Holocaust: Rethinking Curation in the Digital Age <https://ef.huji.ac.il/book/vhh-visual-history-holocaust-rethinking-curation-digital-age>
> currently working for Ludwig Boltzmann Institute for Digital History (LBIDH)  <https://geschichte.lbg.ac.at/team/fabian-schmidt>and Filmuniversität Babelsberg KONRAD WOLF
> upcoming research project: DFG-Filmikonen  <https://www.filmuniversitaet.de/filmuni/aktuelles/news/artikel/detail/filmbilder-aus-der-nazizeit-im-fokus>
> filmproject: Atrocity Film <http://blog.atrocityfilm.com/>
> IMDB <https://www.imdb.com/name/nm1144289/>
> 
> 
> Fabian Schmidt
> Husemannstr. 12
> 10435 Berlin
> 0049 0172 3256513
> 
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