The folks that put good trailers together have talent, and skills honed from years learning from and apprenticing with even better editors. Their efforts deserve the respect due to any expert artisan. To attribute less is the height of anti-intellectual pretentiousness.
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When you export your clip/trailer, you must be careful to preserve the original quality. This means you want to re-encode the video maximum once, and with high quality settings.
The following allows you to extract a clip (ex: mp4/mov, mkv) without re-encoding:
ffmpeg.exe -ss 00:20:00 -i "input.mp4" -t 30 -c copy "output_cut20.mp4"
This will extract a output_cut20.mp4 clip starting at the keyframe before 20min and ending at 00:20:30 (-t duration in seconds). The operation is lossless (ie: the output is not re-encoded just cut and remuxed).
Moreover, the process can be automated. You could extract a clip every 10 minutes for instance with a specified duration.
Maybe some clips will be cut too early, in this case Avidemux is a simple GUI that allows lossless cutting on keyframes.
The clips you select can then be combined in a single file (maybe with the title clip from the same source) or used as a playlist. Your editor can be used for final editing if required.
An automated Avisynth script is easy to use.
you need to install Avisynth+ x64 with LSMASHSource.dll plugin x64 to be able to run it.
One possible refinement would be to specify that segment cuts should occur on detected scene changes.
Last edited by butterw; 8th Sep 2020 at 11:35. Reason: Avisynth+ install info
Thank you all good ideas...
Is this something like what you would like? It is still glitchy but I use it all the time fine because I know of the glitches. It is still time consuming but much less so than all manual because it takes much of the guess work out of cutting and splicing.
1. Drag and drop a video anywhere on this form and it will obtain all the necessary information about the video.
2, Adjust the Scene Variance dropdown and then Click set Scenes Scene changes timing information will be loaded on the first page (multiple pages may result and shown by clicking The page arrows at the top.)
[Attachment 54846 - Click to enlarge]
3. Click show images to show images for each scene change 1st frame. These can be enlarged by LEFT clicking image.
4. RIGHT clicking an image will play that segment for the duration shown to the left of the image.
[Attachment 54847 - Click to enlarge]
5. set each segment to the length (in frames) of the viewed area you wish to cut.
[Attachment 54848 - Click to enlarge]
6. Preview again for the cut length by again Right clicking.
7. Click 'Keep' for each contiguous segment you want joined. I my case of setting the first segment to 3 seconds, I click Keep and End to terminate that segment after 3 seconds.
8.Many Videos can be altered or spliced from different sources so the GOP, B frames, etc are not consistent such as below.
[Attachment 54849 - Click to enlarge]
9. for this reason, clicking build segment will COPY (if Front unchecked otherwise it will be encoded.) It will add a numeric designation to the front of the copied/encoded video
It will also create a list of the final frames to make sure FFMpeg has not altered the last segment more than the normal frame interval (which it will do if you specify the wrong end point to stop on). This can be corrected by Clicking end adjust and adding frames or removing them.
THIS is NECESSARY because although each segment will play correctly, if joined you may have a pause or frozen frame between segments.
[Attachment 54850 - Click to enlarge]
10 if you have problems joining or viewing, these can be corrected on he work horse page.
[Attachment 54851 - Click to enlarge]
As i stated, this is still buggy but I know how to circumvent them until I correct the code. but it does some of what you are asking as well as editing functions others have asked such as:
1. Cloning first or last frame for adjusted times.
2. Creating and adding simple subtitles.
3. Create fade in/out
4. Adjust Subtitle background color, size and font
5. Crop and adjust aspect if necessary. (Partially automation when changing one dimension
6. Much much more even stack and I just added Mirror
If this is something anyone would want in one package I will continue to debug and recode.
Thx for reading and critiques and one posts.
A tool that does video segmentation is useful, ideally with an easy to use GUI that allows you to display/navigate/extract scenes of the analysed video. The content is otherwise overwhelming for a feature length source.
Ex 1 x100min movie:
- 10 x 10min chapters
- 50 x 2min scenes (based on adjustable, smart scene segmentation)
- 1000 keyframe segments if average duration is 6s
- 100*60*24=144000 frames
I originally started my program to cut various segments, usually 1 minute each, and put them together in a sequence that is a seeming short movie without all the slow dead parts. I made it so it is as frame accurate as ffmpeg could be without any jerky quarks between segments. Then I added parts to enhance this like brighten, sharpen, subtitle between segment where action stops by cloning 1st or last frame or last frame so you don't miss anything and also as the movie played without pause. Then I added things like fade in out, add silent audio to voiceless audio, create colored blank video to insert between segments, with and without segments.
Some friend wanted their home movies edited like this but also had parts far away and u added zoom. They also had individual light and dark issues with various segment so I added those features. Then I saw a video with 2 narrow videos side by side to make a regular sized video so I added that. Last night I added mirror so various narrow segments can be mirrored next to each other.
What additional features would be needed for people that wish for segmenting videos?
Yes I see my program would need a way to reference those segments already cut into chapters and assemble them. Right now I create the short videos but must select all that I want joined and drag drop them on the nerve for and adjust the sequence if not alphabetical. Automation would help
Thank you for your reply and suggestion.
Existing chapters are one way of segmenting a mkv video. But they vary a lot movie to movie (ex: 5 to 20 chapters). Timestamps are more useful when associated with a numbered title.
Ex: 04. Title Four 00:20:30.000
They are well supported in players, and even youtube has a named timestamp feature now.
Maybe they should also be considered as an output option.
If no re-encoding is necessary, it makes sense to save the start/stop timestamps of the clip instead of saving the cut video. That way, you could watch the movie or the clip using the same file.