将各种音频和视频源混合到单个视频中 [英] Mixing various audio and video sources into a single video
问题描述
我已经阅读了 FFmpeg-将一个视频叠加到另一个视频上?/a>，(以及许多关于 setpts 的类似问题，标记为 [ffmpeg] >)，并且下面的代码可以正常工作，但是我敢肯定我们可以简化它，并提供更优雅的解决方案.
I've already read FFmpeg - Overlay one video onto another video?, How to overlay 2 videos at different time over another video in single ffmpeg command?, FFmpeg - Multiple videos with 4 areas and different play times (and many similar questions tagged [ffmpeg] about setpts), and the following code is working, but I'm sure we can simplify it, and have a more elegant solution.
我想混合使用不同起点的多种来源(图像和声音):
I'd like to mix multiple sources (image and sound) , with different starting points:
t (seconds) 0 1 2 3 4 5 6 7 8 9 10 11 12 13
test.png [-------------------------------]
a.mp3 [-------]
without_sound.mp4 [-------------------] (overlay at x,y=200,200)
b.mp3 [---]
with_sound.mp4 [---------------------------------------] (overlay at x,y=100,100)
这有效:
ffmpeg -i test.png
-t 2 -i a.mp3
-t 5 -i without_sound.mp4
-t 1 -i b.mp3
-t 10 -i with_sound.mp4
-filter_complex "
[0]setpts=PTS-STARTPTS[s0];
[1]adelay=2000^|2000[s1];
[2]setpts=PTS-STARTPTS+7/TB[s2];
[3]adelay=5000^|5000[s3];
[4]setpts=PTS-STARTPTS+3/TB[s4];
[4:a]adelay=3000^|3000[t4];
[s1][s3][t4]amix=inputs=3[outa];
[s0][s4]overlay=100:100[o2];
[o2][s2]overlay=200:200[outv]
" -map [outa] -map [outv]
out.mp4 -y
但是:
-
我们必须同时使用
setpts和adelay是正常的吗?我尝试了没有adelay的情况，但声音没有移位.换句话说，有没有一种方法可以简化:
is it normal that we have to use both
setptsandadelay? I have tried withoutadelayand then the sound is not shifted. Said differently, is there a way to simplify:
[4]setpts=PTS-STARTPTS+3/TB[s4];
[4:a]adelay=3000^|3000[t4];
?
是否可以仅使用 setpts 和 asetpts 来做到这一点?当我将 adelay = 5000 | 5000 替换为 asetpts = PTS-STARTPTS + 5/TB 时，对于另外一个，它没有给出预期的时移(见下文)
is there a way to do it with setpts and asetpts only? When I replaced adelay=5000|5000 with asetpts=PTS-STARTPTS+5/TB and also for the other one, it didn't give the expected time-shifting (see below)
在类似的问题/答案中，我经常看到 overlay = ...:enable ='between(t，...，...)'，这里似乎不是需要，为什么?
in similar questions/answers I often see overlay=...:enable='between(t,...,...)', here it seems it is not needed, why?
更一般而言，您如何简化这种混合多个音频和视频"? ffmpeg 代码?
More generally, how would you simplify this "mix multiple audio and video" ffmpeg code?
有关第二个要点的更多详细信息:如果我们将 adelay 替换为 asetpts ，
More details about the second bullet point: if we replace adelay by asetpts,
-filter_complex "
[0]setpts=PTS-STARTPTS[s0];
[1]asetpts=PTS-STARTPTS+2/TB[s1];
[2]setpts=PTS-STARTPTS+7/TB[s2];
[3]asetpts=PTS-STARTPTS+5/TB[s3];
[4]setpts=PTS-STARTPTS+3/TB[s4];
[4:a]asetpts=PTS-STARTPTS+3/TB[t4];
[s1][s3][t4]amix=inputs=3[outa];
[s0][s4]overlay=100:100[o2];
[o2][s2]overlay=200:200[outv]
它不起作用:[3]应该从0'05开始，而[4:a]应该从0'03"开始但它们都比[1]在同一时间开始，即从0'02开始.
it doesn't work: [3] should begin at 0'05", and [4:a] at 0'03" but they all begin at the same time than [1], i.e. at 0'02".
amix 似乎只考虑了第一个
It seems that amix only takes the first asetpts in consideration, and discards the others; is it true?
推荐答案
我们必须同时使用setpts和adelay吗?
is it normal that we have to use both setpts and adelay?
是的，前者用于视频流；后者，用于音频.asetpts不适合与amix一起使用，因为后者会忽略开始时间偏移.adelay会从0填充到所需的偏移量.
Yes, the former is for video streams; the latter, for audio. asetpts is not suitable for use with amix since the latter ignores starting time offsets. adelay fills in with silence from 0 to the desired offset.
我经常看到overlay = ...:enable ='between(t，...，...)'，这里似乎不需要，为什么?
I often see overlay=...:enable='between(t,...,...)', here it seems it is not needed, why?
重叠式广告会根据时间戳同步其主要视频帧和重叠式视频帧.如果在两个输入均具有同步帧时希望禁用覆盖，则需要 enable .
Overlay syncs its main and overlay video frames by timestamps. enable is needed if one wishes to disable overlay when synced frames are available for both inputs.
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