了解/控制MLT融化幻灯片显示吗? [英] Understanding/controlling MLT melt slideshow?

查看：154 发布时间：2020/7/13 21:19:33 video-editing mlt

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问题描述

考虑以下bash脚本(在Ubuntu 18.04，melt 6.6.0上)，该脚本使用melt制作幻灯片并在窗口(SDL使用者)中本地播放，主要从 https://superuser.com/questions/833232/create-video-with-5-images-with-fadein-out-effect-in-ffmpeg/834035#834035 -但是这种方法似乎可以在转换过程中缩放图像，并且需要在SDL窗口中播放之前需要相当长一段时间才能渲染"，而这个几乎可以即时播放):

Consider the following bash script (on Ubuntu 18.04, melt 6.6.0), which uses melt to make a slideshow and play it locally in a window (SDL consumer), mostly copied from https://mltframework.org/blog/making_nice_slideshows/ ( edit: I'm aware that's its possible to specify files individually as in https://superuser.com/questions/833232/create-video-with-5-images-with-fadein-out-effect-in-ffmpeg/834035#834035 - but that approach seems to scale images during transition, and takes quite a while to "render" before playing in SDL window, while this one has nearly instant playback):

echo "
description=DV PAL
frame_rate_num=25
frame_rate_den=1
width=720
height=576
progressive=0
sample_aspect_num=59
sample_aspect_den=54
display_aspect_num=4
display_aspect_den=3
colorspace=601
" > my-melt.profile

mkdir tmppics
convert -background lightblue -fill blue -size 3840x2160  -pointsize 200  -gravity center label:"Test A" tmppics/pic_01.jpg
convert -background lightblue -fill blue -size 3840x2160  -pointsize 200  -gravity center label:"Test B" tmppics/pic_02.jpg

melt -verbose -profile ./my-melt.profile \
./tmppics/.all.jpg ttl=6 \
-attach crop center=1 \
-filter luma cycle=6 duration=4 \
-consumer sdl

当我运行上面的命令时，视频显示了两个图像循环，但是帧计数器持续运行，并且无限增加.如何使它在循环很长的确切帧数后停止?
据我所知，输出视频的大小由配置文件控制；也就是说，即使我未指定-profile，也会采用默认值；正确吗?
原始图像如下:

When I run the above command, the video shows the two images loop, but the frame counter keeps on going, increasing indefinitely. How do I make it stop after the exact amount of frames that the loop is long?
As far as I can see, the size of the output video is controlled by a profile; that is, even if I don't specify -profile, a default one is assumed; is that correct?
The original images look like this:

...，视频看起来像这样:

... and the video looks like this:

...这意味着长宽比是错误的；此外，我还能看到锯齿状的边缘，这意味着视频中缩放后的图像没有抗锯齿.

... which means the aspect ratio is wrong; additionally I can see jagged edges, meaning the scaled image in the video is not antialiased.

如何使用正确的宽高比和抗锯齿/平滑功能使图像适合视频尺寸? (我想这与-attach crop center=1有关，但是我找不到关于它的文档).

How do I make the image fit in video size with correct aspect ratio, with antialiasing/smoothing? (I guess it has to do with -attach crop center=1, but I couldn't find documentation on that).

在SDL中查看内容并逐步查看帧时，帧是从0开始编号的，还是从1开始，并且在帧0处仅显示与1相同的帧?

When viewing stuff in SDL and stepping through frames, are frames numbered 0-based, - or are they 1-based, and at frame 0 simply the same frame as 1 is shown?

如果我使用ttl=6和-filter luma cycle=6 duration=4，我会得到:

If I use ttl=6 and -filter luma cycle=6 duration=4, I get this:

...，即可见过渡从帧7开始(帧6是完整图像A)，持续到帧7和8，结束于帧9(是完整图像B)；然后再次在第13帧和第14帧(第15帧是完整图像A)

... that is, visible transition starts at frame 7 (frame 6 is full image A), lasts for frames 7 and 8, and ends at frame 9 (which is full image B); then again at frames 13 and 14 (frame 15 is full image A)

但是，如果我使用ttl=6和-filter luma cycle=6 duration=2，那么我会得到:

However, if I use ttl=6 and -filter luma cycle=6 duration=2, then I get this:

...即没有过渡，图像在第7帧立即更改，然后在第13帧再次更改，依此类推.

... that is, there is no transition, image instantly changes at frame 7, then again at frame 13, etc.

因此，我将第一种情况称为过渡持续时间为2帧，第二种情况称为持续时间为0帧-但选项分别为duration=4和duration=2.谁能解释为什么?这两帧差异在哪里去了?

So, I'd call the first case a transition duration of 2 frames, and the second case a duration of 0 frames - yet the options are duration=4 and duration=2, respectively. Can anyone explain why? Where are those 2 frames of difference gone?

我可以(如果可以的话)如何进行相同的幻灯片显示，除了淡入黑色之外?我想定义每个图像6帧的生存时间"(ttl)，以及4帧的过渡，例如:

Can I - and if so, how - do the same kind of slideshow, except with fade to black? I'd like to define a "time to live" (ttl) of 6 frames per image, and a transition of 4 frames, such that:

然后两帧图像B淡入(与先前的2帧过渡为4帧)，随后又是另外两帧图像B充满(因此图像B为4帧)；
然后一帧图像B淡出，然后一帧黑色(图像B相当于TTL的6帧)；

first, 4 frames are shown of image A;
then one frame image A faded, followed by one frame black (amounting to 6 frames TTL for image A, the last 2 transition);
then two frames image B faded (amounting to 4 frames transition with previous 2), followed by two more frames image B full (so 4 frames here of image B);
then one frame image B faded, followed by one frame black (amounting to 6 frames TTL for image B);

...等等

是否可以说服melt使用globlob选择用于幻灯片显示的图像，而不是使用.all.jpg?据我在 MLT(媒体爱工具)照片幻灯片视频否-但也许还有另一种方法...

Is it possible to persuade melt to use globbing to select images for slideshow, instead of using .all.jpg? As far as I can see on MLT (Media Lovin' Toolkit) Photo Slide Video no - but maybe there is another approach...

了解/控制MLT融化幻灯片显示吗? [英] Understanding/controlling MLT melt slideshow?

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了解/控制MLT融化幻灯片显示吗? [英] Understanding/controlling MLT melt slideshow?

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