fix some a/an typos

Signed-off-by: Lou Logan <lou@lrcd.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/doc/examples/filtering_audio.c b/doc/examples/filtering_audio.c
index 89c80cfd55..6bb24a431d 100644
--- a/doc/examples/filtering_audio.c
+++ b/doc/examples/filtering_audio.c
@@ -65,7 +65,7 @@ static int open_input_file(const char *filename)
     /* select the audio stream */
     ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_AUDIO, -1, -1, &dec, 0);
     if (ret < 0) {
-        av_log(NULL, AV_LOG_ERROR, "Cannot find a audio stream in the input file\n");
+        av_log(NULL, AV_LOG_ERROR, "Cannot find an audio stream in the input file\n");
         return ret;
     }
     audio_stream_index = ret;