diff --git a/libavformat/utils.c b/libavformat/utils.c index 7c30fdf061..28ffaaa223 100644 --- a/libavformat/utils.c +++ b/libavformat/utils.c @@ -815,6 +815,13 @@ static int get_audio_frame_size(AVCodecContext *enc, int size, int mux) if (enc->frame_size > 1) return enc->frame_size; + //For WMA we currently have no other means to calculate duration thus we + //do it here by assuming CBR, which is true for all known cases. + if(!mux && enc->bit_rate>0 && size>0 && enc->sample_rate>0 && enc->block_align>1) { + if (enc->codec_id == CODEC_ID_WMAV1 || enc->codec_id == CODEC_ID_WMAV2) + return ((int64_t)size * 8 * enc->sample_rate) / enc->bit_rate; + } + return -1; }