python - FFmpeg-Python 音频在最终视频中丢失

Question

我试图将视频放在背景图像之上，但输出视频生成时没有音频。有什么办法可以保持音频原样吗？

def ConvertVideo(source,background,start,end,dest):
    stream = ffmpeg.input(source)
    strea1 = ffmpeg.input(background)
    duration = end - start
    stream = stream.trim(start=start,duration=duration).filter('setpts', 'PTS-STARTPTS')
    stream = stream.crop(100,0,1080,720)
    stream = ffmpeg.overlay(strea1,stream,x=0,y=180)
    stream = stream.output(dest)

有谁知道为什么音频会掉线？这个问题有什么解决方法吗？

Answer 1

我们必须明确添加音频流。
类似:ffmpeg.output(overlaid_vid_stream, audio_stream, dest) .

首先使用 FFmpeg CLI 创建合成输入视频和背景(只是为了使发布的解决方案可重现和“自包含”)。

创建带音频的输入视频:

 ffmpeg -y -f lavfi -i testsrc=size=128x72:rate=1 -f lavfi -i sine=frequency=400 -f lavfi -i sine=frequency=1000 -filter_complex "[1:a][2:a]amix=inputs=2" -vcodec libx264 -g 10 -crf 17 -pix_fmt yuv420p -acodec aac -ar 22050 -t 50 in.mp4

创建黄色背景图像:

 ffmpeg.exe -y -f lavfi -i color=yellow:size=128x72 -frames:v 1 background.png

例如，大小为 128x72(假设您的输入为 1280x720)。

以下代码示例适用 trim , setpts , crop和 overlay过滤器，并添加源音频:

source = 'in.mp4'
background = 'background.png'
dest = 'out.mp4'
end = 40
start = 10

duration = end - start

vid_stream = ffmpeg.input(source).video  # Source video stream
audio_stream = ffmpeg.input(source).audio  # Source audio stream
vid_background = ffmpeg.input(background).video  # Background video stream

trimed_vid_stream = vid_stream.trim(start=start, duration=duration).filter('setpts', 'PTS-STARTPTS').crop(10, 0, 108, 72)  # Source video stream after trimming and cropping
overlaid_vid_stream = ffmpeg.overlay(vid_background, trimed_vid_stream, x=0, y=18)  # Video stream overlay of background and trimed_vid_stream

trimed_audio_stream = audio_stream.filter('atrim', start=start, duration=duration).filter('asetpts', 'PTS-STARTPTS')  # Trimming the audio
output_video_and_audio = ffmpeg.output(overlaid_vid_stream, trimed_audio_stream, dest)  # Output - video applies overlaid_vid_stream, and audio applies trimmed source audio

output_video_and_audio.overwrite_output().run() # Execute FFmpeg

我修改了您的命名以使其更有意义(将所有内容命名为 stream 使其难以理解)。
我还删除了该方法，并将参数设置为特定值(只是为了使发布的解决方案可重现)。

该解决方案适用于以下主要阶段:

创建对视频和音频流的引用:

 vid_stream = ffmpeg.input(source).video  # Source video stream
 audio_stream = ffmpeg.input(source).audio  # Source audio stream

定义视频过滤器:

 vid_background = ffmpeg.input(background).video  # Background video stream
 trimed_vid_stream = vid_stream.trim(start=start, duration=duration).filter('setpts', 'PTS-STARTPTS').crop(10, 0, 108, 72)  # Source video stream after trimming and cropping
 overlaid_vid_stream = ffmpeg.overlay(vid_background, trimed_vid_stream, x=0, y=18)  # Video stream overlay of background and trimed_vid_stream

定义音频过滤器(修剪音频):

 trimed_audio_stream = audio_stream.filter('atrim', start=start, duration=duration).filter('asetpts', 'PTS-STARTPTS')  # Trimming the audio

定义输出以包括“过滤”的视频和修剪的音频:

 output_video_and_audio = ffmpeg.output(overlaid_vid_stream, trimed_audio_stream, dest)  # Output - video applies overlaid_vid_stream, and audio applies trimmed source audio

执行 FFmpeg:

 output_video_and_audio.overwrite_output().run() # Execute FFmpeg

示例输出帧:

该视频包括一个哔哔声...