ffmpeg - ss 和 t 的定位之间的结果差异？

Question

和有什么区别

ffmpeg -y -ss 1 -i "test.MP4" -t 2 -c copy "test2.MP4"

和

ffmpeg -y -t 2 -i "test.MP4" -ss 1 -c copy "test2.MP4"

和

ffmpeg -y -ss 1 -t 2 -i "test.MP4" -c copy "test2.MP4"

和

ffmpeg -y -i "test.MP4" -ss 1 -t 2 -c copy "test2.MP4"

Answer 1

来自 https://ffmpeg.org/ffmpeg.html 上的文档:

-ss position (input/output)

When used as an input option (before -i), seeks in this input file to position. [...] When used as an output option (before an output url), decodes but discards input until the timestamps reach position.

和

-t duration (input/output)

When used as an input option (before -i), limit the duration of data read from the input file. When used as an output option (before an output url), stop writing the output after its duration reaches duration.