[FFmpeg-trac] #1723(undetermined:new): Stream selection doesn't check the existence of the stream

[FFmpeg]

#1723: Stream selection doesn't check the existence of the stream
-------------------------------------+-------------------------------------
             Reporter:  burek        |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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 Summary of the bug:

 When the stream selection is used in such a way that it selects a non-
 existing stream, ffmpeg doesn't show any warnings or errors, but rather
 chooses to ignore the issue completely.

 For example, if our input contains 2 video streams and we try to select a
 non-existent video stream like "-c:v:333" it will not complain, but IMHO
 it should, because if a user has specified a command line option for
 something, it means he wants that option to be taken into account. The
 least ffmpeg could do is issue a warning saying it is a non-existent
 stream selected.

 How to reproduce:
 {{{
 % ffmpeg -i input -c:v:333 copy output
 }}}
 Instead of getting an error, warning or something like this:
 {{{
 Stream mapping:
   Stream #0:0 -> #0:0 (copy)
 }}}
 the result is the same as if "-c:v:333 copy" was deleted from cmd line,
 thus ignored totally, using some default encoder like this:
 {{{
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 -> libx264)
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1723>
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