[FFmpeg-cvslog] doc/ffmpeg: document trailing "?" in map option

Lou Logan git at videolan.org
Tue Feb 14 02:32:54 EET 2017

ffmpeg | branch: master | Lou Logan <lou at lrcd.com> | Mon Feb 13 15:26:43 2017 -0900| [1c049d5ffe08b3af36844cdbe7a5950879122b8b] | committer: Lou Logan

doc/ffmpeg: document trailing "?" in map option

This feature was added in 2375a85c36c4941042e6ee58a31d6560bde91d37.

Signed-off-by: Lou Logan <lou at lrcd.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1c049d5ffe08b3af36844cdbe7a5950879122b8b

 doc/ffmpeg.texi | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
index 11b527d..8b08e22 100644
--- a/doc/ffmpeg.texi
+++ b/doc/ffmpeg.texi
@@ -871,7 +871,7 @@ Set the size of the canvas used to render subtitles.
 @section Advanced options
 @table @option
- at item -map [-]@var{input_file_id}[:@var{stream_specifier}][, at var{sync_file_id}[:@var{stream_specifier}]] | @var{[linklabel]} (@emph{output})
+ at item -map [-]@var{input_file_id}[:@var{stream_specifier}][?][, at var{sync_file_id}[:@var{stream_specifier}]] | @var{[linklabel]} (@emph{output})
 Designate one or more input streams as a source for the output file. Each input
 stream is identified by the input file index @var{input_file_id} and
@@ -887,6 +887,11 @@ the source for output stream 1, etc.
 A @code{-} character before the stream identifier creates a "negative" mapping.
 It disables matching streams from already created mappings.
+A trailing @code{?} after the stream index will allow the map to be
+optional: if the map matches no streams the map will be ignored instead
+of failing. Note the map will still fail if an invalid input file index
+is used; such as if the map refers to a non-existant input.
 An alternative @var{[linklabel]} form will map outputs from complex filter
 graphs (see the @option{-filter_complex} option) to the output file.
 @var{linklabel} must correspond to a defined output link label in the graph.
@@ -924,6 +929,13 @@ To map all the streams except the second audio, use negative mappings
 ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
 @end example
+To map the video and audio streams from the first input, and using the
+trailing @code{?}, ignore the audio mapping if no audio streams exist in
+the first input:
+ at example
+ffmpeg -i INPUT -map 0:v -map 0:a? OUTPUT
+ at end example
 To pick the English audio stream:
 ffmpeg -i INPUT -map 0:m:language:eng OUTPUT

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