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authorClément Bœsch <clement.boesch@smartjog.com>2012-01-10 11:47:46 +0100
committerClément Bœsch <ubitux@gmail.com>2012-02-02 14:31:17 +0100
commitd055c3286c979095650453f08a4d69fb6d995f92 (patch)
treee2f1953a90d8f63f9b2213594fc961175ddd0879
parentb90d79ec1f2115ed583399739fd37a97d74f9a64 (diff)
downloadffmpeg-d055c3286c979095650453f08a4d69fb6d995f92.tar.gz
doc: document amerge filter as an alternative for the -map_channel limitation.
-rw-r--r--doc/ffmpeg.texi12
-rw-r--r--doc/filters.texi17
2 files changed, 29 insertions, 0 deletions
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.