[FFmpeg-cvslog] avfilter/af_channelmap: fix error message if FL source channel was missing

[Marton Balint]

ffmpeg | branch: release/6.0 | Marton Balint <cus at passwd.hu> | Mon Mar 18 21:56:58 2024 +0100| [ea2dcb9b3918fb4cbbe2e032c683dc68320145f3] | committer: Marton Balint

avfilter/af_channelmap: fix error message if FL source channel was missing

FL channel ID is 0, so for an unset value we must check for ID < 0.

Regression since 1f96db959c1235bb7079d354e09914a0a2608f62.

Signed-off-by: Marton Balint <cus at passwd.hu>
(cherry picked from commit 9a5627ea9a213c4929020ee8c90bae74788f645c)

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ea2dcb9b3918fb4cbbe2e032c683dc68320145f3
---

 libavfilter/af_channelmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavfilter/af_channelmap.c b/libavfilter/af_channelmap.c
index eb173d20c4..dd323b992b 100644
--- a/libavfilter/af_channelmap.c
+++ b/libavfilter/af_channelmap.c
@@ -167,7 +167,7 @@ static av_cold int channelmap_init(AVFilterContext *ctx)
 
     for (i = 0; i < map_entries; i++) {
         int in_ch_idx = -1, out_ch_idx = -1;
-        int in_ch = 0, out_ch = 0;
+        int in_ch = -1, out_ch = -1;
         static const char err[] = "Failed to parse channel map\n";
         switch (mode) {
         case MAP_ONE_INT:
@@ -382,7 +382,7 @@ static int channelmap_config_input(AVFilterLink *inlink)
 
         if (m->in_channel_idx < 0 || m->in_channel_idx >= nb_channels) {
             av_channel_layout_describe(&inlink->ch_layout, layout_name, sizeof(layout_name));
-            if (m->in_channel) {
+            if (m->in_channel >= 0) {
                 av_channel_name(channel_name, sizeof(channel_name), m->in_channel);
                 av_log(ctx, AV_LOG_ERROR,
                        "input channel '%s' not available from input layout '%s'\n",