AC3ENC_OPT_DOWNMIX_LTRT 1744 libavcodec/ac3enc.c             case AC3ENC_OPT_DOWNMIX_LTRT:  av_strlcpy(strbuf, "ltrt", 32);         break;
AC3ENC_OPT_DOWNMIX_LTRT   51 libavcodec/ac3enc_opts_template.c     {"ltrt", "Lt/Rt Downmix Preferred",         0, AV_OPT_TYPE_CONST, {.i64 = AC3ENC_OPT_DOWNMIX_LTRT  }, INT_MIN, INT_MAX, AC3ENC_PARAM, "dmix_mode"},