[FFmpeg-devel] lavfi/pan: allow negative gain parameters also for other inputs than the first named

Submitted by Moritz Barsnick on Oct. 28, 2016, 12:13 p.m.

Details

Message ID 1477656805-28401-1-git-send-email-barsnick@gmx.net
State Accepted
Commit 0700d02a697e0a2901abc6422edfe72a246bae01
Headers show

Commit Message

Moritz Barsnick Oct. 28, 2016, 12:13 p.m.
Expands the parser to also accept the separator '-' in addition to
'+', and take the negative sign into consideration.

The optional sign for the first factor in the expression is already
covered by parsing for an integer.

Signed-off-by: Moritz Barsnick <barsnick@gmx.net>
---
 doc/filters.texi     |  2 +-
 libavfilter/af_pan.c | 10 +++++++---
 2 files changed, 8 insertions(+), 4 deletions(-)

Comments

Nicolas George Oct. 29, 2016, 1:03 p.m.
Le septidi 7 brumaire, an CCXXV, Moritz Barsnick a écrit :
> Expands the parser to also accept the separator '-' in addition to
> '+', and take the negative sign into consideration.
> 
> The optional sign for the first factor in the expression is already
> covered by parsing for an integer.
> 
> Signed-off-by: Moritz Barsnick <barsnick@gmx.net>
> ---
>  doc/filters.texi     |  2 +-
>  libavfilter/af_pan.c | 10 +++++++---
>  2 files changed, 8 insertions(+), 4 deletions(-)

Still LGTM, of course, thanks.

Regards,
Michael Niedermayer Nov. 23, 2016, 11:55 p.m.
On Sat, Oct 29, 2016 at 03:03:58PM +0200, Nicolas George wrote:
> Le septidi 7 brumaire, an CCXXV, Moritz Barsnick a écrit :
> > Expands the parser to also accept the separator '-' in addition to
> > '+', and take the negative sign into consideration.
> > 
> > The optional sign for the first factor in the expression is already
> > covered by parsing for an integer.
> > 
> > Signed-off-by: Moritz Barsnick <barsnick@gmx.net>
> > ---
> >  doc/filters.texi     |  2 +-
> >  libavfilter/af_pan.c | 10 +++++++---
> >  2 files changed, 8 insertions(+), 4 deletions(-)
> 
> Still LGTM, of course, thanks.

applied

thx

[...]

Patch hide | download patch | download mbox

diff --git a/doc/filters.texi b/doc/filters.texi
index c37fa29..bff4640 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3025,7 +3025,7 @@  output channel layout or number of channels
 
 @item outdef
 output channel specification, of the form:
-"@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
+"@var{out_name}=[@var{gain}*]@var{in_name}[(+-)[@var{gain}*]@var{in_name}...]"
 
 @item out_name
 output channel to define, either a channel name (FL, FR, etc.) or a channel
diff --git a/libavfilter/af_pan.c b/libavfilter/af_pan.c
index fbd79a5..94f1587 100644
--- a/libavfilter/af_pan.c
+++ b/libavfilter/af_pan.c
@@ -102,7 +102,7 @@  static av_cold int init(AVFilterContext *ctx)
 {
     PanContext *const pan = ctx->priv;
     char *arg, *arg0, *tokenizer, *args = av_strdup(pan->args);
-    int out_ch_id, in_ch_id, len, named, ret;
+    int out_ch_id, in_ch_id, len, named, ret, sign = 1;
     int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
     double gain;
 
@@ -178,14 +178,18 @@  static av_cold int init(AVFilterContext *ctx)
                 ret = AVERROR(EINVAL);
                 goto fail;
             }
-            pan->gain[out_ch_id][in_ch_id] = gain;
+            pan->gain[out_ch_id][in_ch_id] = sign * gain;
             skip_spaces(&arg);
             if (!*arg)
                 break;
-            if (*arg != '+') {
+            if (*arg == '-') {
+                sign = -1;
+            } else if (*arg != '+') {
                 av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
                 ret = AVERROR(EINVAL);
                 goto fail;
+            } else {
+                sign = 1;
             }
             arg++;
         }