FFMPEG: how to fill the audio "gap" with silence?

[marcorocchini]

Hi but sorry, I'm a cat

Please I wonder: supposing I have to generate a .wav file using ffmpeg in witch the video duration have to be of the input video file (.avs) taked to ffmpeg. And if there is a difference in the lenght of duration between video and audio source... the final .wav have to be exactly the same of the video duration

for example my video source is input.avs (of 50 seconds) meanwhile my audio source is C0010.MP4 (of 35 seconds)

I need that ffmpeg encode a .wav file so that the total lenght duration is 50 seconds, putting the audio part (source is C0010.MP4) in the first 35 second of the final output, and silence from 35 to 50 seconds

How can I do? thanks

[pandy]

https://ffmpeg.org/ffmpeg-filters.html#apad

[marcorocchini]

really my target is tell to ffmpeg that

if audio source lenght is lower than video.. please fill the gap with silence
if audio source is over lenght the than video .. please cut the audio to fit the video lenght

[mulvya]

Use with apad and shortest

ffmpeg -i input.avs -i C0010.MP4 -map 0:v -map 1:a -af apad -shortest output.mp4

I've left out the audio and video encoding parameters.

[marcorocchini]

ahn ok but I need to generate a audio-only file output .wav and not a mp4 but now I try thanks

[sneaker]

Why don't you do it in AviSynth? Just load both video and audio and add Trim(0, 0) at the end.

[marcorocchini]

but I cannot alwais extract audio correctly

and alwais I cannot extract audio in batch mode (

https://forum.videohelp.com/threads/377488-avisynth-error-attempted-to-cat-request-does-not-exist-!

[marcorocchini]

However I prefer the ffmpeg way: we can suppose to have a video file VIDEOsource.MP4 that have duration of 50 seconds and a

AUDIOsource1.MP4 that is video/audio file of 30 seconds
and
AUDIOsource2.MP4 that is video/audio file of 70 seconds

I would like use ffmpeg so that the final output is a .WAV file based on the video lengt (50 seconds)

so

if the AUDIOsource1.MP4 is the audio source ---> the output .wav have to be of 50 second (30second of audio + 20 of silence)
if the AUDIOsource2.MP4 is the audio source ---> the output .wav have to be of 50 second (the first 50 seconds, and rest cutted)

[marcorocchini]

I have try to put the output as .wav (instead of .mp4) but don't work

ffmpeg.exe  -y -i  VIDEOsource.MP4 -i AUDIOsourceX.MP4 -map 0:v -map 1:a -vcodec mjpeg -shortest -af apad -c:a pcm_s16le marco3.avi

seems almost ok!

this commandline adjust the audio part based on the video lenght

but only I need to output in .wav (and not mp4 or avi)

[marcorocchini]

ffmpeg.exe  -y -i  VIDEOsource.MP4 -i AUDIOsourceX.MP4 -map 0:v -map 1:a -vcodec mjpeg -shortest -af apad -c:a pcm_s16le marco3.wav

don't work because of this