[FFmpeg-user] In case of future deprecation, a backup of audio routing script shared for public servicing.

[Moritz Barsnick]

On Tue, Feb 12, 2019 at 12:26:55 +0800, Sound Yuan wrote:
> Thanks for the suggestion. Forgot to tell that Line 1 is the real output
> whereas Line 2 is a silenced source for nullifying front channels. I use
> two cables separately for rear and front jacks, with earphones attached to
> front one's extension and stereos to the rear's; Would try the quad
> configuration when home after-hours.
[...]
> > > On Feb 11, 2019, at 6:42 PM, Sound Yuan <soundyuanofficial at gmail.com> wrote:
> > >
> > > ffmpeg -f dshow -rtbufsize 4 -i audio="Line 1 (Virtual Audio Cable)" -f
> > dshow -rtbufsize 4 -i audio="Line 2 (Virtual Audio Cable)" -f dshow
> > -rtbufsize 4 -i audio="Line 2 (Virtual Audio Cable)" -filter_complex
> > "[0:a][1:a][2:a]amerge=inputs=3[a]" -map "[a]" -ar 48000 -vn -f wav - |
> > ffmpeg -i - -filter_complex
> > "channelmap=map=FL-BL|FR-BR|FC-FC|LFE-LFE|BL-FL|BR-FR:channel_layout=5.1”
> > -vn -f wav -vol 1024 - | "C:\vlc-3.0.6\vlc.exe" - --prefetch-buffer-size=400

I'm quite sure you can also chain the filters from the first and the
second ffmpeg command. This could in turn reduce some of the latency.

>
$ [...] -filter_complex "[0:a][1:a][2:a]amerge=inputs=3,channelmap=map=FL-BL|FR-BR|FC-FC|LFE-LFE|BL-FL|BR-FR:channel_layout=5.1" [...]

(without judging about the use of the filters for your use-case).

Moritz