[FFmpeg-devel] [PATCH] ffmpeg: implement input file stream disabling

[Michael Niedermayer]

On Thu, Dec 13, 2018 at 01:20:22AM +0530, Gyan wrote:
> 
> On 13-12-2018 12:50 AM, Michael Niedermayer wrote:
> >On Wed, Dec 12, 2018 at 10:25:46AM +0530, Gyan wrote:
> >>On 12-12-2018 03:40 AM, Michael Niedermayer wrote:
> >>>On Mon, Dec 10, 2018 at 08:57:44PM +0530, Gyan wrote:
> >>>>At Michael's suggestion, this patch lets -vn/-an/-sn/-dn work for input
> >>>>files. Individual streams can still be let through e.g.
> >>>>
> >>>>     ffmpeg -an -discard:a:1 none -i file ...
> >>>>
> >>>>will let (only) the 2nd audio stream be seen during stream selection and
> >>>>filtergraph construction.
> >>>>
> >>>>Thanks,
> >>>>Gyan
> >>>>  ffmpeg_filter.c |    7 +++++++
> >>>>  ffmpeg_opt.c    |   17 +++++++++++++++++
> >>>>  2 files changed, 24 insertions(+)
> >>>>212c7bcecbd62329f3f18893c71f464ebeee3b67  0001-ffmpeg-implement-input-file-stream-disabling.patch
> >>>> From 9823a71f2055f2c4c4484536291bbd2afee36a81 Mon Sep 17 00:00:00 2001
> >>>>From: Gyan Doshi <ffmpeg at gyani.pro>
> >>>>Date: Mon, 10 Dec 2018 20:38:20 +0530
> >>>>Subject: [PATCH] ffmpeg: implement input file stream disabling
> >>>>
> >>>>-vn/-an/-sn/-dn can be set to stop processing of streams
> >>>>of said type from an input file.
> >>>isnt this 2 seperate changes ?
> >>>one is adding -vn/-an/-sn/-dn input support and the other is fixing some input
> >>>discard issues related to existing -discard functionality
> >>
> >>Only one change. I provided an example command syntax to show how to
> >>selectively enable streams while leaving others of the same type disabled.
> >You misunderstand me i think
> >patches should be split in self contained changes.
> >part of this patch adds support for -vn/-an/-sn/-dn
> >and other parts are fixing bugs
> >
> >the patch for example adds a error check for disabled filter inputs
> >using this example:
> >ffmpeg -discard all  -i tests/data/asynth-44100-1.wav -i tests/data/asynth-44100-1.wav -filter_complex '[0:a][1:a]amerge=inputs=2[aout]' -map '[aout]'  -f framecrc -
> >
> >This newly added code triggers and prints
> >"Stream specifier ':a' in filtergraph description [0:a][1:a]amerge=inputs=2[aout] matches a disabled input stream."
> >
> >before the patch the code did not error out.
> 
> Actually, I meant to catch and error out for scenarios like,
> 
>     ffmpeg -vn -i input -lavfi [0:v]filter output
> 
> Since there's only one variable to set discard state, it happens to error
> out your command as well. I didn't consider it a bug fix but as due
> diligence for this new 'feature'.
> 
> I can split this in two, if you like.
> 
> Anything else?

more spliting is better, yes
you know your changes better than i do, any self contained bugfix could be
split out. Or maybe all related bugfixes together if you dont want too many
one line patches

thanks

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you drop bombs on a foreign country and kill a hundred thousand
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"unprovoked inhuman terrorist attacks" and use it to justify dropping
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