diff --git a/ffmpeg.c b/ffmpeg.c
index d020b468b3e9c8929eb2d9ea4ba07cb79ff9297d..85633ee2c9ba94c2ee304c2beeae125bef4df3eb 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -1519,6 +1519,7 @@ static int av_encode(AVFormatContext **output_files,
                 codec->sample_rate = icodec->sample_rate;
                 codec->channels = icodec->channels;
                 codec->frame_size = icodec->frame_size;
+                codec->block_align= icodec->block_align;
                 break;
             case CODEC_TYPE_VIDEO:
                 codec->frame_rate = icodec->frame_rate;