diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi index e3a4c755ba..943301a567 100644 --- a/doc/ffmpeg.texi +++ b/doc/ffmpeg.texi @@ -835,6 +835,18 @@ possible, for example, to turn two separate mono streams into a single stereo stream. However spliting a stereo stream into two single channel mono streams is possible. +If you need this feature, a possible workaround is to use the @emph{amerge} +filter. For example, if you need to merge a media (here @file{input.mkv}) with 2 +mono audio streams into one single stereo channel audio stream (and keep the +video stream): + +@example +ffmpeg -i input.mkv -f lavfi -i " +amovie=input.mkv:si=1 [a1]; +amovie=input.mkv:si=2 [a2]; +[a1][a2] amerge" -c:a pcm_s16le -c:v copy output.mkv +@end example + @item -map_metadata[:@var{metadata_spec_out}] @var{infile}[:@var{metadata_spec_in}] (@emph{output,per-metadata}) Set metadata information of the next output file from @var{infile}. Note that those are file indices (zero-based), not filenames. diff --git a/doc/filters.texi b/doc/filters.texi index c6bcf0bdcd..1f3522e08d 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -189,6 +189,23 @@ Example: merge two mono files into a stereo stream: amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge @end example +If you need to do multiple merges (for instance multiple mono audio streams in +a single video media), you can do: +@example +ffmpeg -f lavfi -i " +amovie=input.mkv:si=0 [a0]; +amovie=input.mkv:si=1 [a1]; +amovie=input.mkv:si=2 [a2]; +amovie=input.mkv:si=3 [a3]; +amovie=input.mkv:si=4 [a4]; +amovie=input.mkv:si=5 [a5]; +[a0][a1] amerge [x0]; +[x0][a2] amerge [x1]; +[x1][a3] amerge [x2]; +[x2][a4] amerge [x3]; +[x3][a5] amerge" -c:a pcm_s16le output.mkv +@end example + @section anull Pass the audio source unchanged to the output.