On 3/21/17, Chris Hennes <[email protected]> wrote: > I started with adelay=1000|1000,atrim... and expected that to give me one > second of silence (for a stereo track), but it did not. I take it that it > should have, so I should go back to debugging that? I gave up on it when I > couldn't make sense of the output.
That should give 1 second of silence at start of audio. > ________________________________ > From: Libav-user <[email protected]> on behalf of Paul B Mahol > <[email protected]> > Sent: Tuesday, March 21, 2017 10:53:15 AM > To: This list is about using libavcodec, libavformat, libavutil, libavdevice > and libavfilter. > Subject: Re: [Libav-user] Using libav to insert silence at the beginning of > an audio clip > > On 3/21/17, Chris Hennes <[email protected]> wrote: >> The software I am writing allows a user to combine multiple >> potentially-overlapping audio clips by specifying an in and out point for >> each clip, plus when in the final stream that clip starts. I'm trying to >> string together a single filter graph that will do this and am struggling >> with the start point bit. My thought was to take each of the audio files >> and >> construct a filter chain for them that inserts silence of the required >> length at the beginning, then the atrim'ed audio clip, then an apad to >> the >> end of the required length, so (for just a single audio file), something >> like: >> >> (some kind of silence-generator >> here)[delay0];[in0]atrim=start=1:end=3,apad >> [end0];[delay0][end0]concat=n=2,v=0,a=1[final0] >> >> I can't seem to figure out how to make the concat work, though. No matter >> what technique I use to generate the silence (or non-silence, I've tried >> using sine and anoisesrc), I am getting an "invalid argument". I've tried >> playing around with the ffmpeg exe on the command line, but still can't >> make >> heads or tails of concat. What am I missing? Or is there a better way to >> do >> what I am describing? >> > > Yes, see adelay filter. > _______________________________________________ > Libav-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/libav-user > _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
