当我的音频持续时间小于视频视频持续时间时，如何循环播放音轨ffmpeg

Question

I'm using the follow command to generate a video from images:

"ffmpeg - framerate 1/2 -i storage/emulated/0/myapp/temp/picutre%0d.png" + " -i /storage/emulated/0/myapp/music.mp3 -strict experimental -s " + getScreenResolution() + " -r 30 -vcodec mpeg4 -b 150k -ab 48000 -ac 2 -ar 22050 -shortest " + filename;

My audio duration time is 30s and my total video duration time is 1min. There's a way to loop my audio to complete my video duration? I'm using a lib ffmpeg for android to generate a vídeo on my application.

Answer 1

You have to generate the 1 min audio file. That mean you have to calculate the number of repetition, then create a concat.txt file like this:

file '/path/to/original.mp3'
file '/path/to/original.mp3'

In your case the duration of original audio is 30s, and you need 1 min. So there are only 2 lines in concat.txt file.

Then generate the new audio file:

ffmpeg -t 60 -f concat -i concat.txt -c copy -t 60 output.mp3

Final step is adding new audio file to your video. More details please read the answer of Eugen Rieck here

Answer 2

您可以使用环路滤波器。

"ffmpeg - framerate 1/2 -i storage/emulated/0/myapp/temp/picutre%0d.png" + "-f lavfi -i amovie=/storage/emulated/0/myapp/music.mp3:loop=999 -strict experimental -s " + getScreenResolution() + " -r 30 -vcodec mpeg4 -b 150k -ab 48000 -ac 2 -ar 22050 -shortest " + filename;