如何使用ffmpeg在指定时间为视频添加多段音频

Got it, let's expand on your existing FFmpeg command to handle multiple audio tracks easily. Your current command uses the concat filter to join a 30-second silent track with a single input audio—scaling this to 2, 3, or more audio clips just requires extending that concat chain correctly.

First, let's recap your original command logic #

Your command does two key things:

1. Generates a 30-second silent audio track with aevalsrc=0:d=30[s1]
2. Uses concat to join that silent track with your input audio ([s1][1:a]concat=n=2:v=0:a=1[aout]), where n=2 tells FFmpeg you're joining 2 audio segments

Adding 2 audio clips (plus the initial silent track) #

To add a second audio file, you just need to:

• Add another -i flag for the second audio file
• Update the concat filter to include this new audio stream, and set n=3 (since we now have 3 segments: silent + audio1 + audio2)

Here's the command:

ffmpeg -i input_video.mp4 -i audio1.mp3 -i audio2.mp3 -filter_complex "
  # Generate 30-second silent track
  aevalsrc=0:d=30[s1];
  # Concatenate silent track + audio1 + audio2
  [s1][1:a][2:a]concat=n=3:v=0:a=1[aout]
" -c:v copy -map 0:v -map [aout] output_video.mp4

Adding 3+ audio clips #

For three audio clips, follow the same pattern: add another -i for the third audio, extend the concat input list, and set n=4 (silent + audio1 + audio2 + audio3):

ffmpeg -i input_video.mp4 -i audio1.mp3 -i audio2.mp3 -i audio3.mp3 -filter_complex "
  aevalsrc=0:d=30[s1];
  [s1][1:a][2:a][3:a]concat=n=4:v=0:a=1[aout]
" -c:v copy -map 0:v -map [aout] output_video.mp4

Bonus: Mixing silent tracks between audio clips #

If you want to add silence between audio clips (not just at the start), generate multiple silent tracks and include them in the concat chain. For example: audio1 → 10s silence → audio2 → 5s silence → audio3

ffmpeg -i input_video.mp4 -i audio1.mp3 -i audio2.mp3 -i audio3.mp3 -filter_complex "
  # Generate two different silent tracks
  aevalsrc=0:d=10[s1];
  aevalsrc=0:d=5[s2];
  # Concatenate all segments in order
  [1:a][s1][2:a][s2][3:a]concat=n=5:v=0:a=1[aout]
" -c:v copy -map 0:v -map [aout] output_video.mp4

Critical Notes to Avoid Errors #

• Matching audio specs: All audio segments (silent tracks included) must have the same sample rate, channel count, and format. If they don't, add the aformat filter to standardize them first. For example:

  # Standardize audio1 to stereo, 44.1kHz, FLTP format
  [1:a]aformat=sample_fmts=fltp:sample_rates=44100:channel_layouts=stereo[a1];
  # Do the same for audio2
  [2:a]aformat=sample_fmts=fltp:sample_rates=44100:channel_layouts=stereo[a2];
  # Then concatenate [s1][a1][a2]...
  

• Update n in concat: The n value must always equal the number of segments you're joining. If you have 5 segments, set n=5—this is a common mistake that causes failures.

内容的提问来源于stack exchange，提问作者呂裕翔