{ "duration", "set video duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
{ "d", "set video duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
{ "sar", "set video sample aspect ratio", OFFSET(sar), AV_OPT_TYPE_RATIONAL, {.dbl= 1}, 0, INT_MAX, FLAGS },
{ "duration", "set video duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
{ "d", "set video duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
{ "sar", "set video sample aspect ratio", OFFSET(sar), AV_OPT_TYPE_RATIONAL, {.dbl= 1}, 0, INT_MAX, FLAGS },