From 0700d02a697e0a2901abc6422edfe72a246bae01 Mon Sep 17 00:00:00 2001 From: Moritz Barsnick Date: Fri, 28 Oct 2016 14:13:25 +0200 Subject: [PATCH] lavfi/pan: allow negative gain parameters also for other inputs than the first named 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 Reviewed-by: Nicolas George Signed-off-by: Michael Niedermayer --- doc/filters.texi | 2 +- libavfilter/af_pan.c | 10 +++++++--- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/doc/filters.texi b/doc/filters.texi index b15f78a9a0..b3899b2693 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -3026,7 +3026,7 @@ 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 fbd79a5a42..94f15876f5 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++; }