如何通过多个帧号修剪视频然后使用 FFMPEG 连接 [英] How to trim video by multiple frame numbers then concatenate using FFMPEG

问题描述

使用以下代码，我可以按时间修剪视频:

Using following code, I'm able to trim video by time:

ffmpeg -i input.mp4 -filter_complex \
"[0:v]trim=60:65,setpts=PTS-STARTPTS[v0]; \
 [0:a]atrim=60:65,asetpts=PTS-STARTPTS[a0]; \
 [0:v]trim=120:125,setpts=PTS-STARTPTS[v1];
 [0:a]atrim=120:125,asetpts=PTS-STARTPTS[a1]; \
 [v0][a0][v1][a1]concat=n=2:v=1:a=1[out]" \
-map "[out]" output.mp4

上面的代码修剪了 60-65 秒的视频 &120-125sec 然后连接到 output.mp4 文件中.

Above code trim video from 60-65 sec & 120-125sec then concatenate in output.mp4 file.

需要知道如何使用frame number和concatenate来修剪视频.

Need to know how to trim video by using frame number and concatenate.

是否可以使用Frame Number和fps来获取时间?

Is it possible to get the time by using Frame Number and fps?

frame_1_start = 100 #Frame Number
frame_1_end   = 200 #Frame Number
frame_2_start = 450 #Frame Number
frame_3_end   = 700 #Frame Number
fps = 20 # Frame per second

time_x_1 = frame_1_start/fps
time_x_2 = frame_1_end/fps
time_y_1 = frame_2_start/fps
time_y_2 = frame_2_end/fps

ffmpeg -i input.mp4 -filter_complex \
"[0:v]trim=#{time_x_1}:#{time_x_2},setpts=PTS-STARTPTS[v0]; \
 [0:a]atrim=#{time_x_1}:#{time_x_2},asetpts=PTS-STARTPTS[a0]; \
 [0:v]trim=#{time_y_1}:#{time_y_2},setpts=PTS-STARTPTS[v1];
 [0:a]atrim=#{time_y_1}:#{time_y_2},asetpts=PTS-STARTPTS[a1]; \
 [v0][a0][v1][a1]concat=n=2:v=1:a=1[out]" \
-map "[out]" output.mp4

推荐答案

如trim所示过滤文档使用start_frame和end_frame选项.

ffmpeg -i input.mp4 -filter_complex \
"[0:v]trim=start_frame=25:end_frame=100,setpts=PTS-STARTPTS[v0]; \
 [0:v]trim=start_frame=200:end_frame=300,setpts=PTS-STARTPTS[v1];
 [v0][v1]concat=n=2:v=1:a=0[v]" \
-map "[v]" output.mp4

视频和音频

ffmpeg -i input.mp4 -filter_complex \
"[0:v]trim=start_frame=25:end_frame=100,setpts=PTS-STARTPTS[v0]; \
 [0:a]atrim=1:4,asetpts=PTS-STARTPTS[a0]; \
 [0:v]trim=start_frame=200:end_frame=300,setpts=PTS-STARTPTS[v1];
 [0:a]atrim=8:12,asetpts=PTS-STARTPTS[a1]; \
 [v0][a0][v1][a1]concat=n=2:v=1:a=1[v][a]" \
-map "[v]" -map "[a]" output.mp4

对于 atrim，您可以使用原始命令中的时间戳，或使用 start_sample 和 end_sample 如果您更喜欢使用音频样本.atrim 没有 start_frame 和 end_frame.

For atrim you can use timestamps as in your original command, or use start_sample and end_sample if you prefer to use audio samples instead. atrim does not have start_frame and end_frame.

例如，如果帧速率为 25，并且您希望修剪包括 25-100 帧，则 atrim 将使用 atrim=1:4.

For example, if frame rate is 25, and you want trim to include frames 25-100, then atrim would use atrim=1:4.

您可以使用 ffprobe 获取帧率并检查输入是否有音频.

You can use ffprobe to get frame rate and to check if an input has audio.

这篇关于如何通过多个帧号修剪视频然后使用 FFMPEG 连接的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！