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• Why does an "ffmpeg fail" occur when trying to export frames from my "data_src.mp4" file, while using DeepFaceLab ?

  28 août 2020, par Toby Ryberg

  I've been following this step-by-step videoin installing and using DeepFaceLab on my Macbook Pro, which uses OS Catalina. I've been stuck at the step which begins at the 4:42 mark, where he enters this code :

  


  python main.py videoed extract-video —input-file WORKSPACE/data_src.mp4 —output-dir WORKSPACE/data_src

  


  After entering the command, I'm prompted to enter an FPS value ; no problem. Next, it asks for a file output type, which is where I get tied up— as far as I know. It appears as though I can enter either png or jpeg, but receive the same error message, which looks like this :

  


  / !\ ffmpeg fail, job commandline :['ffmpeg', '-i', '/Users/tobyryberg/Documents/deepfakes/DeepFaceLab/WORKSPACE/data_src.mp4', '-pix_fmt', 'rgb24', '/Users/tobyryberg/Documents/deepfakes/DeepFaceLab/WORKSPACE/data_src/%5d.png']

  


  I have no idea what went wrong, as I BELIEVE that I have been doing everything right thus far. If this is at all necessary information, I've opted to use an 18+ minute long video for my source clip, which is an .mp4 file, without audio. If there's someone out there who has the patience to work with me and figure out what went wrong, I'll be forever grateful !

  


• FFMPEG : cut clips from a long video with "fast seek" while maintaining accuracy

  15 août 2020, par japseow

  I have this 3 hour long video which consists of <1-5 seconds of black frames> — < clip > — <1-5 seconds of black frames> — < clip > — ...

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  I could successfully get the clip without the black frames with the slow seek, but it takes over 4 minutes just for seeking.

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  ffmpeg -y -i "C:\Users\user\Videos\obs\part1.mp4" -ss 4370.48 -to 4384.95 -c:a copy -c:v hevc_nvenc -rc vbr_hq -cq 19 -b:v 10000k -maxrate:v 12500k "C:\Users\user\Videos\obs\____delete1.mp4"

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  I tried using the fast seek which takes only 4 sec, but it includes a 4 sec blackframe chunk at the end of the video. The output that should've been 14 sec long became 18 sec.

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  ffmpeg -y -ss 4370.48 -i "C:\Users\user\Videos\obs\part1.mp4" -to 14.47 -c:a copy -c:v hevc_nvenc -rc vbr_hq -cq 19 -b:v 10000k -maxrate:v 12500k "C:\Users\user\Videos\obs\____delete2.mp4"

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  My video has around 640 clips so it's impractical to wait that long just for seeking, and it'll only get worse when I'll be seeking at around the 2+ hour mark.

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• Standardized "Skip Intro" in MP4 video files ?

  25 mai 2020, par Crissov

  Is there a standardized way to mark up specific parts of a MP4-contained video as skippable, e.g. trailers, recaps, intros/outros, opening/closing credits, in the metadata in the file itself ? If possible, I would like to set this with FFmpeg or MP4box.

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  I know that the mvhd box in MOV files makes it possible to specify a single preview. &#xA;I assume Netflix and the like use specially named or hinted chapters, either from file-internal metadata or from a central database, to provide this feature. &#xA;I want to add this now to videos in my personal library, just in case Kodi, VLC or other players and media centers add support for this feature.

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  Edit List Box elst

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  As mentioned in the first comment, Edit Lists may be a solution. They are specified in section 8.6.6 of ISO/IEC 14496-12:2015 (ISOBMFF), which I partially cite below.

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  moov > trak+ > edts ? > elst*

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  [elst] contains an explicit time-line map. &#xA; Each entry defines part of the track time-line :
  &#xA; by mapping part of the media time-line,
  &#xA; or by indicating ‘empty’ time,
  &#xA; or by defining a ‘dwell’, where a single time-point in the media is held for a period.

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  • version is an integer that specifies the version of this box (0 or 1)

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  • entry_count is an integer that gives the number of entries in the following table

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  • segment_duration is an integer that specifies the duration of this edit segment in units of the timescale in the Movie Header Box

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  • media_time is an integer containing the starting time within the media of this edit segment (in media time scale units, in composition time). If this field is set to –1, it is an empty edit. The last edit in a track shall never be an empty edit. Any difference between the duration in the Movie Header Box, and the track’s duration is expressed as an implicit empty edit at the end.

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  • media_rate specifies the relative rate at which to play the media corresponding to this edit segment. If this value is 0, then the edit is specifying a ‘dwell’ : the media at media-time is presented for the segment-duration. Otherwise this field shall contain the value 1.

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